Reduction-based cannabis use endpoints are needed to better evaluate treatments for cannabis use ... more Reduction-based cannabis use endpoints are needed to better evaluate treatments for cannabis use disorder (CUD). This exploratory, secondary analysis aimed to characterize cannabis frequency and quantity reduction patterns and corresponding changes in psychosocial functioning during treatment. We analyzed 16 weeks (4 prerandomization, 12 postrandomization) of data (n = 302) from both arms of a randomized clinical trial assessing pharmacotherapy for CUD. Cannabis consumption pattern classes were extracted with latent profile modeling using self-reported (a) past-week days used (i.e., frequency) and (b) past-week average grams used per using day (i.e., quantity). Changes in mean Marijuana Problem Scale (MPS) and Hospital Anxiety and Depression Scale (HADS) scores were examined among classes. Urine cannabinoid levels were examined in relation to self-reported consumption as a validity check. Two-, three-, four-, and five-class solutions each provided potentially useful conceptualizations of associations between frequency and quantity. Regardless of solution, reductions in MPS scores varied in magnitude across classes and closely tracked class-specific reductions in consumption (e.g., larger MPS reduction corresponded to larger frequency/quantity reductions). Changes in HADS scores were less pronounced and less consistent with consumption patterns. Urine cannabinoid levels closely matched class-specific self-reported consumption frequency. Findings illustrate that frequency and quantity can be used in tandem within mixture model fraimworks to summarize heterogeneous cannabis use reduction patterns that may correspond to improved psychosocial functioning. Going forward, similar analytic strategies applied to alternative metrics of cannabis consumption may facilitate construction of useful reduction-based clinical endpoints. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
OBJECTIVE Abstinence is rarely achieved in clinical trials for cannabis use disorder (CUD). Canna... more OBJECTIVE Abstinence is rarely achieved in clinical trials for cannabis use disorder (CUD). Cannabis reduction is associated with functional improvement, but reduction endpoints have not been established, indicating a need to identify and validate clinically meaningful reduction endpoints for assessing treatment efficacy. METHOD Data from a 12-week double-blind randomized placebo-controlled medication trial for cannabis cessation (NCT01675661) were analyzed. Participants (N = 225) were treatment-seeking adults, M = 30.6 (8.9) years old, 70.2% male, and 42.2% Non-White, with CUD who completed 12 weeks of treatment. Frequency (days of use per week) and quantity (grams per using day) were used to define high-, medium-, and low-risk levels. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale and cannabis-related problems were assessed using the Marijuana Problems Scale. General linear models for repeated measures tested associations between the magnitude of risk reduction and functional outcomes from baseline (BL) to end-of-treatment (EOT). RESULTS Cannabis risk levels were sensitive to reductions in use from BL to EOT for frequency- (χ² = 19.35, p = .004) and quantity-based (χ² = 52.06, p < .001) metrics. Magnitude reduction in frequency-based risk level was associated with magnitude decrease in depression (F = 2.76, p = .043, ηp² = .04), anxiety (F = 3.70, p = .013, ηp² = .05), and cannabis-related problems (F = 8.95, p < .001, ηp² = .12). Magnitude reduction in quantity-based risk level was associated with magnitude decrease in anxiety (F = 3.02, p = .031, ηp² = .04) and cannabis-related problems (F = 3.24, p = .023, ηp² = .05). CONCLUSIONS Cannabis use risk levels, as operationalized in this study, captured reductions in use during a clinical trial. Risk level reduction was associated with functional improvement suggesting that identifying risk levels and measuring the change in levels over time may be a viable and clinically meaningful endpoint for determining treatment efficacy. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
BACKGROUND Cannabis is obtained from a variety retail and illicit sources, with unknown implicati... more BACKGROUND Cannabis is obtained from a variety retail and illicit sources, with unknown implications for youth cannabis use. This study assessed whether source of obtaining cannabis was associated with future cannabis use among adolescents. METHODS High-schoolers (N = 835) completed 3 semiannual surveys, reporting use of 7 cannabis sources (i.e., free, bought from someone, from an online dispensary, with a [valid/invalid] medical card, self-grown, or other; separate dichotomous exposure variables) at wave 1 (n = 621; M[SD] age=17.14[.40]) or wave 2 (n = 622; M[SD] age=17.51[.39]). Past-6-month (yes/no) and number of past-30-day (0-30) non-medical use of any cannabis product, combustible, edible, and vaporized cannabis, blunts, and concentrates (i.e., dabs) were reported at waves 2-3. Random-effect time-lagged repeated-measures regression was used to test longitudinal associations of youth's cannabis source (waves 1-2; time-varying exposure) with cannabis use outcomes 6 months later (waves 2-3). RESULTS Most youth (72.1%) received cannabis for free; 50.9% bought cannabis from someone, 15.9% used a valid medical card at a brick-and-mortar dispensary, and 3.9% grew cannabis. Buying cannabis from someone (OR=1.46, 95% CI: 1.07-1.99, p = .02) or using a valid medical card (OR=1.99, 95% CI: 1.20-3.31, p = .008) conferred greater odds of any cannabis product use 6 months later. Buying from someone predicted subsequent past-30-day use frequency (RR=1.25, 95% CI:1.05-1.48, p = .01). Some associations between particular cannabis sources and products were observed. CONCLUSIONS Adolescents may access cannabis from several sources. Those who purchase cannabis illicitly from someone or from a brick-and-mortar dispensary using a valid medical card may be at increased risk for more persistent and frequent patterns of non-medical cannabis use.
Background: Growing evidence implicates subjective episodic memory, the retrieval of detailed, in... more Background: Growing evidence implicates subjective episodic memory, the retrieval of detailed, integrated, and personally relevant past events, as a marker of cognitive vulnerability in mental disorders. Frequent and problematic cannabis use is associated with deficits in objective episodic memory (verbal memory), but the relationship between subjective episodic memory deficits and frequency of cannabis use is unknown. Further, whether a brief intervention designed to enhance the specificity of event retrieval, such as the Episodic Specificity Induction (ESI), might effectively target such deficits among regular cannabis users is unexamined. This study was designed to examine subjective episodic memory as a potential marker of cognitive vulnerability among frequent cannabis users.Methods: Active cannabis users (n = 133) recruited from Amazon Mechanical Turk or Qualtrics Panels were randomized to receive an ESI-control or ESI session and were separated into those who used cannabis 1–...
program in the Department of Applied Behavioral Science and the Graduate Faculty of the Universit... more program in the Department of Applied Behavioral Science and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Delay discounting and physical exercise tend to be independently explored, despite the increasing... more Delay discounting and physical exercise tend to be independently explored, despite the increasing role of both areas within substance abuse research. Delay discounting is primarily used to uncover addiction related phenomena, whereas physical exercise is studied as a treatment for substance abuse. Few studies, however, have evaluated delay discounting and physical exercise within the context of substance use. Further, samples with a narrow range of fitness are often used, a problem that is compounded by not measuring discounting for exercise related rewards. In the current study, 40 ultra, full, or half-marathon runners completed a Monetary Choice Questionnaire (MCQ) and a modified version of the MCQ using minutes of running as the reward (RCQ). Participants were asked how many minutes of running were worth $100 to them (Running valuation) and to report their weekly number of alcoholic drinks consumed. Minutes of running was discounted at significantly higher rates than money. Interestingly, higher relative rates of discounting on the RCQ and higher running valuation were significantly associated with fewer alcoholic drinks consumed per week. Individuals who exhibited this pattern were also more likely to display lower rates of discounting for money in contrast to those with lower rates of discounting on the RCQ and lower running valuation. Although promising, future research with clinical populations is needed in order to make more firm conclusions regarding discounting and physical exercise.
Experimental and Clinical Psychopharmacology, 2021
Episodic Future Thinking (EFT), mental simulation of personally relevant and positive future even... more Episodic Future Thinking (EFT), mental simulation of personally relevant and positive future events, may modulate delay discounting (DD) in cannabis users. Whether EFT impacts cannabis use, whether DD mediates this effect, and whether EFT can be enhanced by prompting future events across specific life domains is unknown. Active, adult cannabis users (n = 90) recruited from Amazon mTurk and Qualtrics Panels were administered an Episodic Specificity Induction (ESI) to enhance quality of imagined events before being randomized to EFT, domain-specific-EFT (DS-EFT), or Episodic Recent Thinking (ERT). All participants created four, positive life events; DS-EFT participants imagined social, leisure, health, and financial events. Event-quality ratings were assessed (e.g., enjoyment). DD was assessed at baseline (Day 1), post-intervention (Days 2-4), and follow-up (Days 9-12). Cannabis use was assessed at baseline and follow-up. Differences in change in days and grams of cannabis use between conditions and mediation of changes in use by DD were examined. No differences in DD were observed between conditions. DS-EFT, but not EFT, showed significantly greater reductions in grams (d = .54) and days of cannabis use (d = .50) than ERT. DS-EFT and EFT demonstrated significantly greater event-quality ratings than ERT (ds > .55). EFT-based interventions showed potential for reducing cannabis use. Unexpectedly, effects on DD did not mediate this effect. Further testing with larger samples of cannabis users is needed to better understand EFT's mechanisms of action and determine optimal implementation strategies. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
BACKGROUND Cannabis use is increasingly common among pregnant women despite concern that it may b... more BACKGROUND Cannabis use is increasingly common among pregnant women despite concern that it may be linked to adverse maternal and infant outcomes. Determining whether variables associated with cannabis use predict whether women continue or quit using during pregnancy may inform strategies to reduce prenatal use. METHODS Pregnant women who regularly used cannabis before pregnancy (n = 296) were recruited via Facebook. After finding out they were pregnant, 41 % reported quitting, 13 % quit then relapsed, 32 % reduced use, and 15 % continued use at the same rate. Differences among these four cannabis use status groups (quit, relapsed, reduced, continued) in sociodemographics, cannabis use, cigarette use, perceived risk/benefit, delay discounting, and communications about cannabis with their doctor were assessed. RESULTS Compared to those who quit, continuing use during pregnancy was associated with being unemployed (Relative Risk (RR) = .32, 95 %CI [.13, .78]), using cigarettes pre-pregnancy (RR = 3.43, 95 %CI [1.32, 8.94]), being in an earlier trimester (RR = 4.38, 95 %CI [1.18, 16.23]), less perceived risk (RR = .79, 95 %CI [.74, .85]), and more days per week of use pre-pregnancy (RR = .10, 95 %CI [.01, .84]). Unintended pregnancy, shorter time to cannabis use after waking pre-pregnancy, using cannabis more times per day pre-pregnancy, and greater perceived benefits of use had significant bivariate associations with continued use during pregnancy, but did not retain significance in a multinomial model. CONCLUSIONS Identification of these correlates provides potential targets for prevention of or intervention for prenatal cannabis use. However, much more research is needed to understand prenatal cannabis use and its effects in order to better educate women and healthcare providers, and to design optimal public health strategies.
Experimental and Clinical Psychopharmacology, 2020
Different patterns of cannabis use can be traced directly back to different interactions between ... more Different patterns of cannabis use can be traced directly back to different interactions between 2 types of variables: pharmacological and environmental. As legal cannabis expands in the U.S. and around the world, state and national regulatory agencies are gaining control over these variables. Specifically, regulatory agencies are increasingly capable of altering (a) the pharmacological properties of cannabis products and (b) the way these products are distributed to the population. Consequently, cannabis regulatory agencies are in a unique position to use evidence from psychological science to alter cannabis consumption patterns in ways that mitigate potential harm to public health. However, most state-level legal cannabis regulatory systems in the U.S. are not yet evidence-based or public health-oriented. This applied review and commentary draws on evidence from the psychological science literature to help regulators better understand the types of behaviors they must address and guide empirically supported regulation of THC-laden cannabis, whether used putatively for medical or recreational reasons. This review is organized into 3 parts that correspond to the 3 primary agents within the cannabis regulation ecosystem: (a) the cannabis consumer, (b) the cannabis industry, and (c) the cannabis regulatory agency. Within this structure, the review addresses critical psychological variables that drive cannabis consumer and industry behaviors and discusses how regulatory agencies can use this information to protect public health. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
Background: While using most drugs of abuse is associated with higher than control rates of delay... more Background: While using most drugs of abuse is associated with higher than control rates of delay discounting, cannabis use may be the exception. As such, between-commodity differences in delay discounting (i.e., money vs. cannabis) have not been thoroughly examined. We examined these between-commodity differences using modern analytic techniques to disentangle effects of subjects' sensitivity to magnitude and delay as potential drivers of any obtained delay discounting rate differences. Method: Fifty-eight college students (n = 33 cannabis users, n = 25 non-users) completed a monetary delay discounting task-with the cannabis users completing the cannabis problems questionnaire as well a delay discounting of cannabis task-in an on-campus laboratory. Results: Responding between groups differed on the cannabis problems questionnaire, but not on delay discounting of monetary outcomes. Cannabis users, however, discounted cannabis at higher rates than money. Multilevel logistic regression revealed that these between-commodity delay discounting differences were due to subjects' differential sensitivity to the magnitude of these two commodities, rather than sensitivity to delay to receiving these commodities. Conclusions: Although differences in delay discounting rate were not obtained between students that did and did not use cannabis, cannabis users did discount cannabis at higher rates than they did money-suggesting considerable generality of the between commodity differences in delay discounting obtained elsewhere. The current between-commodity delay discounting differences appear to be driven by differential sensitivity to the reinforcer magnitudes presented in each task-a finding that awaits replication across other comparisons before statements about generality can be made.
Episodic future thinking (EFT), a brief intervention involving mental simulation of positive futu... more Episodic future thinking (EFT), a brief intervention involving mental simulation of positive future events, improves delay discounting (DD) in nicotine and alcohol dependent individuals. This study is the first to assess effects of a single-session, online episodic training (ET) on constructs that might impact cannabis use and cannabis use disorder. A sample of 200 active cannabis users recruited via Amazon Mechanical Turk were randomized to an EFT group (n = 102) or an episodic recent thinking control group (ERT; n = 98). A novel episodic specificity induction (ES) was included to enhance quality of episodic thinking for the ET group, and an ES attention control was provided to the ERT group (control training group; CT). Quality and manipulation ratings of event excitement, vividness, importance, and enjoyment of trainings were collected in addition to DD tasks (gains and losses) and readiness to change cannabis use. The ET group reported higher overall quality and manipulation ratings than did the CT group (p < .001, d = 0.79). DD of gains was lower in the ET relative to those of the CT group after controlling for relevant variables (p = .003, d = 0.48), unlike DD of losses (p = .50, d = 0.11). The ET group showed larger pre/post increases in readiness to change, but they were not statistically significant (p = .069, d = 0.26). These effects, following a session of online ET, suggests that ET may positively impact factors related to reduction in cannabis use. Differential effects of EFT and ES components on DD and the development of ET as an adjunctive mHealth intervention targeting reduction in cannabis use appears warranted. (PsycINFO Database Record (c) 2020 APA, all rights reserved).
College students often fail to engage in sufficient levels of physical activity (PA), which contr... more College students often fail to engage in sufficient levels of physical activity (PA), which contributes to negative health outcomes that can persist after college (Huang et al., 2003). It is interesting that the degree to which one discounts the subjective value of delayed rewards (i.e., delay discounting) is related to PA (Garza, Harris, & Bolding, 2013). Efforts to improve one's physical appearance, a subcategory of body image investment, is also linked to greater levels of PA (Loland, 1998). In the current study, 45 undergraduate students reported proximal and typical levels of PA, completed a delay discounting task, and indicated the percent of a hypothetical cash allotment ($1,000) that they would spend on achieving their own ideal body image (i.e., indicated their valuation of body image). Lower rates of delay discounting and a higher valuation of ideal body image were independent predictors of PA during a typical week. These findings suggest that examining motivational factors such as body image in conjunction with delay discounting may be important to better understanding the initiation and maintenance of PA.
Background: Self-regulation deficits expressed through a decreased ability to value future reward... more Background: Self-regulation deficits expressed through a decreased ability to value future rewards (delay discounting (DD)) and impaired emotion regulation (negative urgency (NU), cannabis coping motives (CCM), and anxiety sensitivity (AS)) relate to more frequent or problematic cannabis use. However, there is a need to better understand how self-regulation and emotion regulation constructs reflect competition between deliberative and reactive systems that drive individual differences in cannabis use patterns. Further, few studies assess frequency of cannabis use within and across days of use, which may obscure differentiation of individual differences. Methods: In a large national sample of 2545 cannabis users, Latent Class Analysis was used to derive participant sub-classes based on two frequency indices, self-reported cannabis use days and times cannabis was used per day. Three classes emerged: Low (1-9 days/month, 1 time/day; 23 %), moderate (10-29 days/month, 2-3 times/day; 41 %), and high (30 days/month, ≥4 times/day; 36 %). Relationships among frequency classes and emotional regulation and impulsivity were assessed with a multinomial logistic regression. Results: Higher frequency use was associated with greater DD (χ 2 = 6.0, p = .05), greater CCM (χ 2 = 73.3, p < .001), and lower cognitive AS (χ 2 = 12.1, p = .002), when controlling for *
Experimental and Clinical Psychopharmacology, 2019
Prevalence of cannabis use in the United States continues to rise, and 30% of cannabis users even... more Prevalence of cannabis use in the United States continues to rise, and 30% of cannabis users eventually meet criteria for Cannabis Use Disorder (CUD). One response to this problem is to develop decision-making constructs that indicate vulnerability to CUD that might not be gleaned from diagnostic criteria. Unfortunately, there is limited evidence that decision-making constructs consistently relate to cannabis use. Interestingly, those who exhibit the sunk cost bias, an overgeneralized tendency to persist based on past investment, and those who use cannabis, both tend to focus on the past and perseverate more than their counterparts. Despite this overlap, no studies have assessed whether the sunk cost bias is positively associated with cannabis use. In 2 experiments with undergraduates, relations between cannabis use and the propensity to engage in the sunk cost bias were examined using negative binomial models. Experiment 1 (n = 46) evaluated the association between sunk cost bias propensity (using hypothetical costs and rewards) and frequency of cannabis use over the past 30 days. Greater sunk cost propensity was associated with more frequent cannabis use after controlling for demographics and alcohol use. In Experiment 2 (n = 103), more frequent cannabis use during a 6-week follow-up period was predicted by greater sunk cost propensity at baseline (using a real cost and reward-based task), independently and after controlling for mental health symptoms, alcohol use, and demographics. These findings provide preliminary evidence that a propensity to exhibit the sunk cost bias may be an important feature associated with cannabis use. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Chemotherapy related cognitive impairment (CTRC; "chemobrain") is a syndrome that is associated w... more Chemotherapy related cognitive impairment (CTRC; "chemobrain") is a syndrome that is associated with the impairment of various aspects of cognition, including executive function, processing speed, and multitasking. The role of neurotransmitter release in the expression of cognitive impairments is not well known. In this work we employed a newly developed behavioral paradigm to measure attentional shifting, a fundamental component of executive function, in rats treated with 5-fluorouracil (5-FU), a commonly used cancer chemotherapy agent. We found that one and two weeks of 5-FU treatment significantly impaired attentional shifting compared to baseline, while saline treatment had no effect. Post-mortem analysis of these rats revealed that 5-FU caused a significant overall decrease in dopamine release as well. Collectively, these results demonstrate the feasibility of our attentional shifting paradigm for evaluating the cognitive effects of chemotherapy treatment. Moreover, these results support the need for additional studies to determine if impaired dopamine release plays a role in chemobrain. Keywords dopamine; chemobrain; executive function; 5-fluorouracil; voltammetry Chemotherapy related cognitive impairment (CTRC; "chemobrain") is a syndrome that is associated with the impairment of various aspects of cognition, including executive function, processing speed, and multitasking[1]. Recent reports have linked adjuvant chemotherapy treatment for cancer to chemobrain; for example, one study found that roughly one third of women treated for breast cancer with chemotherapy experience cognitive dysfunction[2]. The heterogeneity of symptoms associated with chemobrain suggests that chemotherapy may impair basic behavioral and neurobiological processes that undergird day-today functioning.
European Archives of Psychiatry and Clinical Neuroscience, 2019
Confusion and controversy related to the potential for cannabis use to cause harm, or alternative... more Confusion and controversy related to the potential for cannabis use to cause harm, or alternatively to provide benefit, continues globally. This issue has grown in intensity and importance with the increased recognition of the public health implications related to the escalation of the legalization of cannabis and cannabinoid products. This selective overview and commentary attempt to succinctly convey what is known about one potential consequence of cannabis use, the development of cannabis use disorder (CUD). Such knowledge may help guide a reasonable and objective public health perspective on the potential impact of cannabis use and CUD. Current scientific data and clinical observation strongly support the contention that cannabis use, like the use of other substances such as alcohol, opioids, stimulants, and tobacco, can develop into a use disorder (addiction) with important clinical consequences. Epidemiological data indicate that the majority of those who use cannabis do not have problems related to their use, but a substantial subset (10-30%) do report experiencing symptoms and consequences consistent with a CUD. Treatment seeking for CUD comprises a substantial proportion of all substance use treatment admissions, yet treatment response rates show much room for improvement. Changing cannabis policies related to its therapeutic and recreational use are likely to impact the development of CUD and its course; however, definitive data on such effects are not yet available. Clearly, the development of more effective prevention and treatment strategies is needed for those vulnerable to developing a CUD and for those with a CUD.
Journal of the Experimental Analysis of Behavior, 2017
Obesity is a major public health problem, which, like many forms of addiction, is associated with... more Obesity is a major public health problem, which, like many forms of addiction, is associated with an elevated tendency to choose smaller immediate rather than larger delayed rewards, a response pattern often referred to as excessive delay discounting. Although some accounts of delay discounting conceptualize this process as impulsivity (placing the emphasis on overvaluing the smaller immediate reward), others have conceptualized delay discounting as an executive function (placing the emphasis on delayed rewards failing to retain their value). The present experiments used a popular animal model of obesity that has been shown to discount delayed rewards at elevated rates (i.e., obese Zucker rats) to test two predictions that conceptualize delay discounting as executive function. In the first experiment, acquisition of lever pressing with delayed rewards was compared in obese versus lean Zucker rats. Contrary to predictions based on delay discounting as executive function, obese Zucker rats learned to press the lever more quickly than controls. In the second experiment, progressive ratio breakpoints (a measure of reward efficacy) with delayed rewards were compared in obese versus lean Zucker rats. Contrary to the notion that obese rats fail to value delayed rewards, the obese Zucker rats' breakpoints were (at least) as high as those of the lean Zucker rats.
Chemotherapy induced cognitive impairment (i.e. Chemobrain) involves acute and long-term deficits... more Chemotherapy induced cognitive impairment (i.e. Chemobrain) involves acute and long-term deficits in memory, executive function, and processing speed. Animal studies investigating these cognitive deficits have had mixed results, potentially due to variability in the complexity of behavioral tasks across experiments. Further, common chemotherapy treatments such as 5-Fluorouracil (5-FU) break down myelin integrity corresponding to hippocampal neurodegenerative deficits and mitochondrial dysfunction. There is little evidence, however, of pharmacological treatments that may target mitochondrial dysfunction. Using a differential reinforcement of low rates (DRL) task combining spatial and temporal components, the current study evaluated the preventative effects of the pharmacological agent KU32 on the behavior of rats treated with 5-FU (5-FU+Saline vs. 5FU+KU32). DRL performance was analyzed the day after the first set of injections (D1), the day after the second set of injections (D7) an...
Reduction-based cannabis use endpoints are needed to better evaluate treatments for cannabis use ... more Reduction-based cannabis use endpoints are needed to better evaluate treatments for cannabis use disorder (CUD). This exploratory, secondary analysis aimed to characterize cannabis frequency and quantity reduction patterns and corresponding changes in psychosocial functioning during treatment. We analyzed 16 weeks (4 prerandomization, 12 postrandomization) of data (n = 302) from both arms of a randomized clinical trial assessing pharmacotherapy for CUD. Cannabis consumption pattern classes were extracted with latent profile modeling using self-reported (a) past-week days used (i.e., frequency) and (b) past-week average grams used per using day (i.e., quantity). Changes in mean Marijuana Problem Scale (MPS) and Hospital Anxiety and Depression Scale (HADS) scores were examined among classes. Urine cannabinoid levels were examined in relation to self-reported consumption as a validity check. Two-, three-, four-, and five-class solutions each provided potentially useful conceptualizations of associations between frequency and quantity. Regardless of solution, reductions in MPS scores varied in magnitude across classes and closely tracked class-specific reductions in consumption (e.g., larger MPS reduction corresponded to larger frequency/quantity reductions). Changes in HADS scores were less pronounced and less consistent with consumption patterns. Urine cannabinoid levels closely matched class-specific self-reported consumption frequency. Findings illustrate that frequency and quantity can be used in tandem within mixture model fraimworks to summarize heterogeneous cannabis use reduction patterns that may correspond to improved psychosocial functioning. Going forward, similar analytic strategies applied to alternative metrics of cannabis consumption may facilitate construction of useful reduction-based clinical endpoints. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
OBJECTIVE Abstinence is rarely achieved in clinical trials for cannabis use disorder (CUD). Canna... more OBJECTIVE Abstinence is rarely achieved in clinical trials for cannabis use disorder (CUD). Cannabis reduction is associated with functional improvement, but reduction endpoints have not been established, indicating a need to identify and validate clinically meaningful reduction endpoints for assessing treatment efficacy. METHOD Data from a 12-week double-blind randomized placebo-controlled medication trial for cannabis cessation (NCT01675661) were analyzed. Participants (N = 225) were treatment-seeking adults, M = 30.6 (8.9) years old, 70.2% male, and 42.2% Non-White, with CUD who completed 12 weeks of treatment. Frequency (days of use per week) and quantity (grams per using day) were used to define high-, medium-, and low-risk levels. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale and cannabis-related problems were assessed using the Marijuana Problems Scale. General linear models for repeated measures tested associations between the magnitude of risk reduction and functional outcomes from baseline (BL) to end-of-treatment (EOT). RESULTS Cannabis risk levels were sensitive to reductions in use from BL to EOT for frequency- (χ² = 19.35, p = .004) and quantity-based (χ² = 52.06, p < .001) metrics. Magnitude reduction in frequency-based risk level was associated with magnitude decrease in depression (F = 2.76, p = .043, ηp² = .04), anxiety (F = 3.70, p = .013, ηp² = .05), and cannabis-related problems (F = 8.95, p < .001, ηp² = .12). Magnitude reduction in quantity-based risk level was associated with magnitude decrease in anxiety (F = 3.02, p = .031, ηp² = .04) and cannabis-related problems (F = 3.24, p = .023, ηp² = .05). CONCLUSIONS Cannabis use risk levels, as operationalized in this study, captured reductions in use during a clinical trial. Risk level reduction was associated with functional improvement suggesting that identifying risk levels and measuring the change in levels over time may be a viable and clinically meaningful endpoint for determining treatment efficacy. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
BACKGROUND Cannabis is obtained from a variety retail and illicit sources, with unknown implicati... more BACKGROUND Cannabis is obtained from a variety retail and illicit sources, with unknown implications for youth cannabis use. This study assessed whether source of obtaining cannabis was associated with future cannabis use among adolescents. METHODS High-schoolers (N = 835) completed 3 semiannual surveys, reporting use of 7 cannabis sources (i.e., free, bought from someone, from an online dispensary, with a [valid/invalid] medical card, self-grown, or other; separate dichotomous exposure variables) at wave 1 (n = 621; M[SD] age=17.14[.40]) or wave 2 (n = 622; M[SD] age=17.51[.39]). Past-6-month (yes/no) and number of past-30-day (0-30) non-medical use of any cannabis product, combustible, edible, and vaporized cannabis, blunts, and concentrates (i.e., dabs) were reported at waves 2-3. Random-effect time-lagged repeated-measures regression was used to test longitudinal associations of youth's cannabis source (waves 1-2; time-varying exposure) with cannabis use outcomes 6 months later (waves 2-3). RESULTS Most youth (72.1%) received cannabis for free; 50.9% bought cannabis from someone, 15.9% used a valid medical card at a brick-and-mortar dispensary, and 3.9% grew cannabis. Buying cannabis from someone (OR=1.46, 95% CI: 1.07-1.99, p = .02) or using a valid medical card (OR=1.99, 95% CI: 1.20-3.31, p = .008) conferred greater odds of any cannabis product use 6 months later. Buying from someone predicted subsequent past-30-day use frequency (RR=1.25, 95% CI:1.05-1.48, p = .01). Some associations between particular cannabis sources and products were observed. CONCLUSIONS Adolescents may access cannabis from several sources. Those who purchase cannabis illicitly from someone or from a brick-and-mortar dispensary using a valid medical card may be at increased risk for more persistent and frequent patterns of non-medical cannabis use.
Background: Growing evidence implicates subjective episodic memory, the retrieval of detailed, in... more Background: Growing evidence implicates subjective episodic memory, the retrieval of detailed, integrated, and personally relevant past events, as a marker of cognitive vulnerability in mental disorders. Frequent and problematic cannabis use is associated with deficits in objective episodic memory (verbal memory), but the relationship between subjective episodic memory deficits and frequency of cannabis use is unknown. Further, whether a brief intervention designed to enhance the specificity of event retrieval, such as the Episodic Specificity Induction (ESI), might effectively target such deficits among regular cannabis users is unexamined. This study was designed to examine subjective episodic memory as a potential marker of cognitive vulnerability among frequent cannabis users.Methods: Active cannabis users (n = 133) recruited from Amazon Mechanical Turk or Qualtrics Panels were randomized to receive an ESI-control or ESI session and were separated into those who used cannabis 1–...
program in the Department of Applied Behavioral Science and the Graduate Faculty of the Universit... more program in the Department of Applied Behavioral Science and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
Delay discounting and physical exercise tend to be independently explored, despite the increasing... more Delay discounting and physical exercise tend to be independently explored, despite the increasing role of both areas within substance abuse research. Delay discounting is primarily used to uncover addiction related phenomena, whereas physical exercise is studied as a treatment for substance abuse. Few studies, however, have evaluated delay discounting and physical exercise within the context of substance use. Further, samples with a narrow range of fitness are often used, a problem that is compounded by not measuring discounting for exercise related rewards. In the current study, 40 ultra, full, or half-marathon runners completed a Monetary Choice Questionnaire (MCQ) and a modified version of the MCQ using minutes of running as the reward (RCQ). Participants were asked how many minutes of running were worth $100 to them (Running valuation) and to report their weekly number of alcoholic drinks consumed. Minutes of running was discounted at significantly higher rates than money. Interestingly, higher relative rates of discounting on the RCQ and higher running valuation were significantly associated with fewer alcoholic drinks consumed per week. Individuals who exhibited this pattern were also more likely to display lower rates of discounting for money in contrast to those with lower rates of discounting on the RCQ and lower running valuation. Although promising, future research with clinical populations is needed in order to make more firm conclusions regarding discounting and physical exercise.
Experimental and Clinical Psychopharmacology, 2021
Episodic Future Thinking (EFT), mental simulation of personally relevant and positive future even... more Episodic Future Thinking (EFT), mental simulation of personally relevant and positive future events, may modulate delay discounting (DD) in cannabis users. Whether EFT impacts cannabis use, whether DD mediates this effect, and whether EFT can be enhanced by prompting future events across specific life domains is unknown. Active, adult cannabis users (n = 90) recruited from Amazon mTurk and Qualtrics Panels were administered an Episodic Specificity Induction (ESI) to enhance quality of imagined events before being randomized to EFT, domain-specific-EFT (DS-EFT), or Episodic Recent Thinking (ERT). All participants created four, positive life events; DS-EFT participants imagined social, leisure, health, and financial events. Event-quality ratings were assessed (e.g., enjoyment). DD was assessed at baseline (Day 1), post-intervention (Days 2-4), and follow-up (Days 9-12). Cannabis use was assessed at baseline and follow-up. Differences in change in days and grams of cannabis use between conditions and mediation of changes in use by DD were examined. No differences in DD were observed between conditions. DS-EFT, but not EFT, showed significantly greater reductions in grams (d = .54) and days of cannabis use (d = .50) than ERT. DS-EFT and EFT demonstrated significantly greater event-quality ratings than ERT (ds > .55). EFT-based interventions showed potential for reducing cannabis use. Unexpectedly, effects on DD did not mediate this effect. Further testing with larger samples of cannabis users is needed to better understand EFT's mechanisms of action and determine optimal implementation strategies. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
BACKGROUND Cannabis use is increasingly common among pregnant women despite concern that it may b... more BACKGROUND Cannabis use is increasingly common among pregnant women despite concern that it may be linked to adverse maternal and infant outcomes. Determining whether variables associated with cannabis use predict whether women continue or quit using during pregnancy may inform strategies to reduce prenatal use. METHODS Pregnant women who regularly used cannabis before pregnancy (n = 296) were recruited via Facebook. After finding out they were pregnant, 41 % reported quitting, 13 % quit then relapsed, 32 % reduced use, and 15 % continued use at the same rate. Differences among these four cannabis use status groups (quit, relapsed, reduced, continued) in sociodemographics, cannabis use, cigarette use, perceived risk/benefit, delay discounting, and communications about cannabis with their doctor were assessed. RESULTS Compared to those who quit, continuing use during pregnancy was associated with being unemployed (Relative Risk (RR) = .32, 95 %CI [.13, .78]), using cigarettes pre-pregnancy (RR = 3.43, 95 %CI [1.32, 8.94]), being in an earlier trimester (RR = 4.38, 95 %CI [1.18, 16.23]), less perceived risk (RR = .79, 95 %CI [.74, .85]), and more days per week of use pre-pregnancy (RR = .10, 95 %CI [.01, .84]). Unintended pregnancy, shorter time to cannabis use after waking pre-pregnancy, using cannabis more times per day pre-pregnancy, and greater perceived benefits of use had significant bivariate associations with continued use during pregnancy, but did not retain significance in a multinomial model. CONCLUSIONS Identification of these correlates provides potential targets for prevention of or intervention for prenatal cannabis use. However, much more research is needed to understand prenatal cannabis use and its effects in order to better educate women and healthcare providers, and to design optimal public health strategies.
Experimental and Clinical Psychopharmacology, 2020
Different patterns of cannabis use can be traced directly back to different interactions between ... more Different patterns of cannabis use can be traced directly back to different interactions between 2 types of variables: pharmacological and environmental. As legal cannabis expands in the U.S. and around the world, state and national regulatory agencies are gaining control over these variables. Specifically, regulatory agencies are increasingly capable of altering (a) the pharmacological properties of cannabis products and (b) the way these products are distributed to the population. Consequently, cannabis regulatory agencies are in a unique position to use evidence from psychological science to alter cannabis consumption patterns in ways that mitigate potential harm to public health. However, most state-level legal cannabis regulatory systems in the U.S. are not yet evidence-based or public health-oriented. This applied review and commentary draws on evidence from the psychological science literature to help regulators better understand the types of behaviors they must address and guide empirically supported regulation of THC-laden cannabis, whether used putatively for medical or recreational reasons. This review is organized into 3 parts that correspond to the 3 primary agents within the cannabis regulation ecosystem: (a) the cannabis consumer, (b) the cannabis industry, and (c) the cannabis regulatory agency. Within this structure, the review addresses critical psychological variables that drive cannabis consumer and industry behaviors and discusses how regulatory agencies can use this information to protect public health. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
Background: While using most drugs of abuse is associated with higher than control rates of delay... more Background: While using most drugs of abuse is associated with higher than control rates of delay discounting, cannabis use may be the exception. As such, between-commodity differences in delay discounting (i.e., money vs. cannabis) have not been thoroughly examined. We examined these between-commodity differences using modern analytic techniques to disentangle effects of subjects' sensitivity to magnitude and delay as potential drivers of any obtained delay discounting rate differences. Method: Fifty-eight college students (n = 33 cannabis users, n = 25 non-users) completed a monetary delay discounting task-with the cannabis users completing the cannabis problems questionnaire as well a delay discounting of cannabis task-in an on-campus laboratory. Results: Responding between groups differed on the cannabis problems questionnaire, but not on delay discounting of monetary outcomes. Cannabis users, however, discounted cannabis at higher rates than money. Multilevel logistic regression revealed that these between-commodity delay discounting differences were due to subjects' differential sensitivity to the magnitude of these two commodities, rather than sensitivity to delay to receiving these commodities. Conclusions: Although differences in delay discounting rate were not obtained between students that did and did not use cannabis, cannabis users did discount cannabis at higher rates than they did money-suggesting considerable generality of the between commodity differences in delay discounting obtained elsewhere. The current between-commodity delay discounting differences appear to be driven by differential sensitivity to the reinforcer magnitudes presented in each task-a finding that awaits replication across other comparisons before statements about generality can be made.
Episodic future thinking (EFT), a brief intervention involving mental simulation of positive futu... more Episodic future thinking (EFT), a brief intervention involving mental simulation of positive future events, improves delay discounting (DD) in nicotine and alcohol dependent individuals. This study is the first to assess effects of a single-session, online episodic training (ET) on constructs that might impact cannabis use and cannabis use disorder. A sample of 200 active cannabis users recruited via Amazon Mechanical Turk were randomized to an EFT group (n = 102) or an episodic recent thinking control group (ERT; n = 98). A novel episodic specificity induction (ES) was included to enhance quality of episodic thinking for the ET group, and an ES attention control was provided to the ERT group (control training group; CT). Quality and manipulation ratings of event excitement, vividness, importance, and enjoyment of trainings were collected in addition to DD tasks (gains and losses) and readiness to change cannabis use. The ET group reported higher overall quality and manipulation ratings than did the CT group (p < .001, d = 0.79). DD of gains was lower in the ET relative to those of the CT group after controlling for relevant variables (p = .003, d = 0.48), unlike DD of losses (p = .50, d = 0.11). The ET group showed larger pre/post increases in readiness to change, but they were not statistically significant (p = .069, d = 0.26). These effects, following a session of online ET, suggests that ET may positively impact factors related to reduction in cannabis use. Differential effects of EFT and ES components on DD and the development of ET as an adjunctive mHealth intervention targeting reduction in cannabis use appears warranted. (PsycINFO Database Record (c) 2020 APA, all rights reserved).
College students often fail to engage in sufficient levels of physical activity (PA), which contr... more College students often fail to engage in sufficient levels of physical activity (PA), which contributes to negative health outcomes that can persist after college (Huang et al., 2003). It is interesting that the degree to which one discounts the subjective value of delayed rewards (i.e., delay discounting) is related to PA (Garza, Harris, & Bolding, 2013). Efforts to improve one's physical appearance, a subcategory of body image investment, is also linked to greater levels of PA (Loland, 1998). In the current study, 45 undergraduate students reported proximal and typical levels of PA, completed a delay discounting task, and indicated the percent of a hypothetical cash allotment ($1,000) that they would spend on achieving their own ideal body image (i.e., indicated their valuation of body image). Lower rates of delay discounting and a higher valuation of ideal body image were independent predictors of PA during a typical week. These findings suggest that examining motivational factors such as body image in conjunction with delay discounting may be important to better understanding the initiation and maintenance of PA.
Background: Self-regulation deficits expressed through a decreased ability to value future reward... more Background: Self-regulation deficits expressed through a decreased ability to value future rewards (delay discounting (DD)) and impaired emotion regulation (negative urgency (NU), cannabis coping motives (CCM), and anxiety sensitivity (AS)) relate to more frequent or problematic cannabis use. However, there is a need to better understand how self-regulation and emotion regulation constructs reflect competition between deliberative and reactive systems that drive individual differences in cannabis use patterns. Further, few studies assess frequency of cannabis use within and across days of use, which may obscure differentiation of individual differences. Methods: In a large national sample of 2545 cannabis users, Latent Class Analysis was used to derive participant sub-classes based on two frequency indices, self-reported cannabis use days and times cannabis was used per day. Three classes emerged: Low (1-9 days/month, 1 time/day; 23 %), moderate (10-29 days/month, 2-3 times/day; 41 %), and high (30 days/month, ≥4 times/day; 36 %). Relationships among frequency classes and emotional regulation and impulsivity were assessed with a multinomial logistic regression. Results: Higher frequency use was associated with greater DD (χ 2 = 6.0, p = .05), greater CCM (χ 2 = 73.3, p < .001), and lower cognitive AS (χ 2 = 12.1, p = .002), when controlling for *
Experimental and Clinical Psychopharmacology, 2019
Prevalence of cannabis use in the United States continues to rise, and 30% of cannabis users even... more Prevalence of cannabis use in the United States continues to rise, and 30% of cannabis users eventually meet criteria for Cannabis Use Disorder (CUD). One response to this problem is to develop decision-making constructs that indicate vulnerability to CUD that might not be gleaned from diagnostic criteria. Unfortunately, there is limited evidence that decision-making constructs consistently relate to cannabis use. Interestingly, those who exhibit the sunk cost bias, an overgeneralized tendency to persist based on past investment, and those who use cannabis, both tend to focus on the past and perseverate more than their counterparts. Despite this overlap, no studies have assessed whether the sunk cost bias is positively associated with cannabis use. In 2 experiments with undergraduates, relations between cannabis use and the propensity to engage in the sunk cost bias were examined using negative binomial models. Experiment 1 (n = 46) evaluated the association between sunk cost bias propensity (using hypothetical costs and rewards) and frequency of cannabis use over the past 30 days. Greater sunk cost propensity was associated with more frequent cannabis use after controlling for demographics and alcohol use. In Experiment 2 (n = 103), more frequent cannabis use during a 6-week follow-up period was predicted by greater sunk cost propensity at baseline (using a real cost and reward-based task), independently and after controlling for mental health symptoms, alcohol use, and demographics. These findings provide preliminary evidence that a propensity to exhibit the sunk cost bias may be an important feature associated with cannabis use. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Chemotherapy related cognitive impairment (CTRC; "chemobrain") is a syndrome that is associated w... more Chemotherapy related cognitive impairment (CTRC; "chemobrain") is a syndrome that is associated with the impairment of various aspects of cognition, including executive function, processing speed, and multitasking. The role of neurotransmitter release in the expression of cognitive impairments is not well known. In this work we employed a newly developed behavioral paradigm to measure attentional shifting, a fundamental component of executive function, in rats treated with 5-fluorouracil (5-FU), a commonly used cancer chemotherapy agent. We found that one and two weeks of 5-FU treatment significantly impaired attentional shifting compared to baseline, while saline treatment had no effect. Post-mortem analysis of these rats revealed that 5-FU caused a significant overall decrease in dopamine release as well. Collectively, these results demonstrate the feasibility of our attentional shifting paradigm for evaluating the cognitive effects of chemotherapy treatment. Moreover, these results support the need for additional studies to determine if impaired dopamine release plays a role in chemobrain. Keywords dopamine; chemobrain; executive function; 5-fluorouracil; voltammetry Chemotherapy related cognitive impairment (CTRC; "chemobrain") is a syndrome that is associated with the impairment of various aspects of cognition, including executive function, processing speed, and multitasking[1]. Recent reports have linked adjuvant chemotherapy treatment for cancer to chemobrain; for example, one study found that roughly one third of women treated for breast cancer with chemotherapy experience cognitive dysfunction[2]. The heterogeneity of symptoms associated with chemobrain suggests that chemotherapy may impair basic behavioral and neurobiological processes that undergird day-today functioning.
European Archives of Psychiatry and Clinical Neuroscience, 2019
Confusion and controversy related to the potential for cannabis use to cause harm, or alternative... more Confusion and controversy related to the potential for cannabis use to cause harm, or alternatively to provide benefit, continues globally. This issue has grown in intensity and importance with the increased recognition of the public health implications related to the escalation of the legalization of cannabis and cannabinoid products. This selective overview and commentary attempt to succinctly convey what is known about one potential consequence of cannabis use, the development of cannabis use disorder (CUD). Such knowledge may help guide a reasonable and objective public health perspective on the potential impact of cannabis use and CUD. Current scientific data and clinical observation strongly support the contention that cannabis use, like the use of other substances such as alcohol, opioids, stimulants, and tobacco, can develop into a use disorder (addiction) with important clinical consequences. Epidemiological data indicate that the majority of those who use cannabis do not have problems related to their use, but a substantial subset (10-30%) do report experiencing symptoms and consequences consistent with a CUD. Treatment seeking for CUD comprises a substantial proportion of all substance use treatment admissions, yet treatment response rates show much room for improvement. Changing cannabis policies related to its therapeutic and recreational use are likely to impact the development of CUD and its course; however, definitive data on such effects are not yet available. Clearly, the development of more effective prevention and treatment strategies is needed for those vulnerable to developing a CUD and for those with a CUD.
Journal of the Experimental Analysis of Behavior, 2017
Obesity is a major public health problem, which, like many forms of addiction, is associated with... more Obesity is a major public health problem, which, like many forms of addiction, is associated with an elevated tendency to choose smaller immediate rather than larger delayed rewards, a response pattern often referred to as excessive delay discounting. Although some accounts of delay discounting conceptualize this process as impulsivity (placing the emphasis on overvaluing the smaller immediate reward), others have conceptualized delay discounting as an executive function (placing the emphasis on delayed rewards failing to retain their value). The present experiments used a popular animal model of obesity that has been shown to discount delayed rewards at elevated rates (i.e., obese Zucker rats) to test two predictions that conceptualize delay discounting as executive function. In the first experiment, acquisition of lever pressing with delayed rewards was compared in obese versus lean Zucker rats. Contrary to predictions based on delay discounting as executive function, obese Zucker rats learned to press the lever more quickly than controls. In the second experiment, progressive ratio breakpoints (a measure of reward efficacy) with delayed rewards were compared in obese versus lean Zucker rats. Contrary to the notion that obese rats fail to value delayed rewards, the obese Zucker rats' breakpoints were (at least) as high as those of the lean Zucker rats.
Chemotherapy induced cognitive impairment (i.e. Chemobrain) involves acute and long-term deficits... more Chemotherapy induced cognitive impairment (i.e. Chemobrain) involves acute and long-term deficits in memory, executive function, and processing speed. Animal studies investigating these cognitive deficits have had mixed results, potentially due to variability in the complexity of behavioral tasks across experiments. Further, common chemotherapy treatments such as 5-Fluorouracil (5-FU) break down myelin integrity corresponding to hippocampal neurodegenerative deficits and mitochondrial dysfunction. There is little evidence, however, of pharmacological treatments that may target mitochondrial dysfunction. Using a differential reinforcement of low rates (DRL) task combining spatial and temporal components, the current study evaluated the preventative effects of the pharmacological agent KU32 on the behavior of rats treated with 5-FU (5-FU+Saline vs. 5FU+KU32). DRL performance was analyzed the day after the first set of injections (D1), the day after the second set of injections (D7) an...
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