Objective: Although the effectiveness of interpersonal psychotherapy (IPT) and cognitive therapy ... more Objective: Although the effectiveness of interpersonal psychotherapy (IPT) and cognitive therapy (CT) for major depression has been established, little is known about how and for whom they work and how they compare in the long term. The latter is especially relevant for IPT because research on its long-term effects has been limited. This overview paper summarizes findings from a Dutch randomized controlled trial on the effects and mechanisms of change of IPT versus CT for major depression. Methods: Adult outpatients with depression (N=182) were randomly assigned to CT (N=76), IPT (N=75), or a 2-month waitlist control group followed by patient's treatment of choice (N=31). The primary outcome was depression severity. Other outcomes were quality of life, social and general psychological functioning, and scores on various mechanism measures. Interventions were compared at the end of treatment and up to 17 months follow-up. Results: On average, IPT and CT were both superior to waitlist, and their outcomes did not differ significantly from one another. However, the pathway through which change occurred appeared to differ. For a majority of participants, one of the interventions was predicted to be more beneficial than the other. No support for the theoretical models of change was found. Conclusions: Outcomes of IPT and CT did not appear to differ significantly. IPT may have an enduring effect not different from that of CT. The field would benefit from further refinement of study methods to disentangle mechanisms of change and from advances in the field of personalized medicine (i.e., person-specific analyses and treatment selection methods).
Objective: This study tested the role of habituation of eating desires and violation of overeatin... more Objective: This study tested the role of habituation of eating desires and violation of overeating expectancies during food cue exposure in obese women. Method: 52 obese females were randomised into a two-session exposure condition aimed at habituation, a twosession exposure condition aimed at expectancy violation, or a no-treatment control condition. Eating in the absence of hunger of foods included during cue exposure (i.e., exposed foods) and foods not included during cue exposure (i.e., non-exposed foods), and duration of exposure were measured. Results: Both cue exposure conditions ate significantly less of the exposed foods compared to the control condition, though there were no differences between both types of exposure. No differences were found between conditions regarding the eating of non-exposed foods. In addition, the duration of exposure was not different between both cue exposure conditions. Conclusions: While food cue exposure in obese women led to less eating of exposed foods, focusing on either habituation of eating desires or expectancy violation did not matter. It is discussed why exposure works.
UvA-DARE is a service provided by the library of the University of Amsterdam () Clinical effectiv... more UvA-DARE is a service provided by the library of the University of Amsterdam () Clinical effectiveness of cognitive therapy v. interpersonal psychotherapy for depression: results of a randomized controlled trial
The network perspective to psychopathology posits that mental disorders emerge from dynamic inter... more The network perspective to psychopathology posits that mental disorders emerge from dynamic interactions among psychopathology-relevant variables. Ecological Momentary Assessment (EMA) is frequently used to obtain measures of these variables. Currently, there is no set of EMA items available that covers the entire range of psychopathology, though there is agreement that EMA studies should go beyond single disorders in line with the transdiagnostic turn the field is taking. The current study aims to fill this gap in three steps. First, 96 clinicians were surveyed to provide three EMA constructs for up to three disorders they specialize in, as well as three EMA constructs from a transdiagnostic perspective. Second, 12 focus groups were conducted with clinical experts for specific diagnoses (e.g., mood disorders, anxiety disorders). Finally, a selection of items was made by consensus among the researchers. Two raters independently coded the online survey responses, with an inter-rater agreement of 87.3%. Jaccard indices showed up to 52.6% overlap in EMA items across diagnoses. The most frequently reported transdiagnostic constructs were mood, sleep quality, and stress. A final set of EMA items was created based on how frequently an item was mentioned and informativeness, balancing completeness across diagnoses and participant burden.
Although the effectiveness of cognitive therapy (ct) and interpersonal psychotherapy (ipt) for de... more Although the effectiveness of cognitive therapy (ct) and interpersonal psychotherapy (ipt) for depression has been well established, little is known about how, how long and for whom they work.<br/> AIM: To summarize findings from a large rct to the (differential) effects and mechanisms of change of ct/ipt for depression.<br/> METHOD: 182 adult depressed outpatients were randomized to ct (n = 76), ipt (n = 75), or a two-month wait-list-control condition (n = 31). Primary outcome was depression severity (bdi-ii). Other outcomes were quality of life, social and general psychological functioning and various potential process measures. Interventions were compared at the end of treatment, and up to 17 months follow-up.<br/> RESULTS: Overall, ct and ipt were both superior to the wait-list, but did not differ significantly from one another. However, the pathway through which therapeutic change occurred appeared to be different for ct and ipt, and many patients were predicted to have a clinically meaningful advantage in one of the two interventions. We did not find empirical support for the theoretical models of change.<br/> CONCLUSION: (Long-term) outcomes of ct and ipt appear to not differ significantly. The field would benefit from further refinement of research methods to disentangle mechanisms of change, and from advances in the field of personalized medicine.
Frontiers in Behavioral Neuroscience, Apr 21, 2020
Background: People with overweight have stronger reactivity (e.g., subjective craving) to food cu... more Background: People with overweight have stronger reactivity (e.g., subjective craving) to food cues than lean people, and this reactivity is positively associated with food intake. Cue reactivity is a learned response that can be reduced with food cue exposure therapy. Objectives: It was hypothesized that participants after food cue exposure therapy would show reduced neural activity in brain regions related to food cue reactivity and increased neural activity in brain regions related to inhibitory-control as compared to participants receiving a control lifestyle intervention. Method: Neural activity of 10 women with overweight (BMI ≥ 27 kg/m 2 ) in response to individually tailored visually presented palatable high-caloric food stimuli was examined before vs. after a cue exposure intervention (n = 5) or a control lifestyle (n = 5) intervention. Data were analyzed case-by-case. Results: Neural responses to food stimuli were reduced in food-cue-reactivity-related brain regions after the lifestyle intervention in most participants, and generally not after the cue exposure therapy. Moreover, cue exposure did not lead to increased activity in inhibitory-control-related brain regions. However, decreased neural activity after cue exposure was found in most participants in the lateral occipital complex (LOC), which suggests a decreased visual salience of high-caloric food stimuli. Receiving a cue exposure therapy did not lead to expected neural responses. As cue exposure relies on inhibitory learning mechanisms, differences in contexts (e.g., environments and food types) between the intervention setting and the scanning sessions may explain the general lack of effect of cue-exposure on neural activity.
Journal of Behavior Therapy and Experimental Psychiatry, Mar 1, 2018
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
Previous research on EMA data of mental disorders was mainly focused on multivariate regression-b... more Previous research on EMA data of mental disorders was mainly focused on multivariate regression-based approaches modeling each individual separately. This paper goes a step further towards exploring the use of non-linear interpretable machine learning (ML) models in classification problems. ML models can enhance the ability to accurately predict the occurrence of different behaviors by recognizing complicated patterns between variables in data. To evaluate this, the performance of various ensembles of trees are compared to linear models using imbalanced synthetic and real-world datasets. After examining the distributions of AUC scores in all cases, non-linear models appear to be superior to baseline linear models. Moreover, apart from personalized approaches, group-level prediction models are also likely to offer an enhanced performance. According to this, two different nomothetic approaches to integrate data of more than one individuals are examined, one using directly all data during training and one based on knowledge distillation. Interestingly, it is observed that in one of the two real-world datasets, knowledge distillation method achieves improved AUC scores (mean relative change of +17% compared to personalized) showing how it can benefit EMA data classification and performance.
In the field of psychopathology, Ecological Momentary Assessment (EMA) methodological advancement... more In the field of psychopathology, Ecological Momentary Assessment (EMA) methodological advancements have offered new opportunities to collect time-intensive, repeated and intra-individual measurements. This way, a large amount of data has become available, providing the means for further exploring mental disorders. Consequently, advanced machine learning (ML) methods are needed to understand data characteristics and uncover hidden and meaningful relationships regarding the underlying complex psychological processes. Among other uses, ML facilitates the identification of similar patterns in data of different individuals through clustering. This paper focuses on clustering multivariate time-series (MTS) data of individuals into several groups. Since clustering is an unsupervised problem, it is challenging to assess whether the resulting grouping is successful. Thus, we investigate different clustering methods based on different distance measures and assess them for the stability and quality of the derived clusters. These clustering steps are illustrated on a real-world EMA dataset, including 33 individuals and 15 variables. Through evaluation, the results of kernel-based clustering methods appear promising to identify meaningful groups in the data. So, efficient representations of EMA data play an important role in clustering.
Current Opinion in Clinical Nutrition and Metabolic Care, Nov 1, 2018
The dominant view in the literature is that increased neural reactivity to high-caloric palatable... more The dominant view in the literature is that increased neural reactivity to high-caloric palatable foods in the mesocorticolimbic system is a stable-specific characteristic of obese people. In this review, we argue that this viewpoint may not be justified, and we propose that the neural response to food stimuli is dynamic, and in synchrony with the current motivational and cognitive state of an individual. We will further motivate why a clear mental task in the scanner is a necessity for drawing conclusions from neural activity, and why multivariate approaches to functional MRI (fMRI) data-analysis may carry the field forward. From the reviewed literature we draw the conclusions that: neural food-cue reactivity depends strongly on cognitive factors such as the use of cognitive regulation strategies, task demands, and focus of attention; neural activity in the mesocorticolimbic system is not proportionate to the hedonic value of presented food stimuli; and multivariate approaches to fMRI data-analysis have shown that hedonic value can be decoded from multivoxel patterns of neural activity. Future research should take the dynamic nature of food-reward processing into account and take advantage from state-of-the-art multivariate approaches to fMRI data-analysis.
High-sugar/high-fat foods are related to binge-eating behaviour and especially people with low in... more High-sugar/high-fat foods are related to binge-eating behaviour and especially people with low inhibitory control may encounter elevated difficulties to resist their intake. Incentive sensitization to food-related cues might lead to increased motivated attention towards these stimuli and to cueinduced craving. To investigate the combined influence of olfactory and visual stimuli on craving, inhibitory control and motivated attention, 20 healthy controls and 19 individuals with binge-eating viewed chocolate and neutral pictures, primed by chocolate or neutral odours. Subjective craving and electroencephalogram activity were recorded during the task. N2 and Late Positive Potential (LPP) amplitudes were analysed. Patients reported higher craving than controls. Subjective craving, N2 and LPP amplitudes were higher for chocolate versus neutral pictures. Patients showed a higher relative increase in N2 amplitudes to chocolate versus neutral pictures than controls. Chocolate images induced significant increases in craving, motivated attention and measures of cognitive control. Chocolate odour might potentiate the craving response to visual stimuli, especially in patients with binge-eating.
Brain responses to food are thought to reflect food’s rewarding value. We propose that brain resp... more Brain responses to food are thought to reflect food’s rewarding value. We propose that brain responses to food are more dynamic and hypothesize that brain responses to food depend on attentional focus. Food pictures (high-caloric/low-caloric, palatable/unpalatable) were presented during fMRI-scanning, while attentional focus (hedonic/health/neutral) was induced in 52 female participants varying in dietary restraint. The level of brain activity was hardly different between palatable versus unpalatable foods or high-caloric versus low-caloric foods. Activity in several brain regions was higher in hedonic than in health or neutral attentional focus (p &lt; 0.05, FWE-corrected). Palatability and calorie content could be decoded from multi-voxel activity patterns (p &lt; 0.05, FDR-corrected). Dietary restraint did not significantly influence brain responses to food. So, level of brain activity in response to food stimuli depends on attentional focus, and may reflect salience, not reward value. Palatability and calorie content are reflected in patterns of brain activity.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Behavior Therapy and Experimental Psychiatry, Jun 1, 2020
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
The purpose of this article is to critically evaluate the following claims derived from contempor... more The purpose of this article is to critically evaluate the following claims derived from contemporary theoretical models of attentional bias (AB) for food-and drug-related stimuli: (a) AB is a characteristic feature of obesity and addiction, (b) AB predicts future behavior, (c) AB exerts a causal influence on consummatory behavior, and (d) AB reflects appetitive motivational processes. Method: A focused discussion of the relevant literature is presented. Results: The available evidence reveals inconsistencies with the aforementioned claims. Specifically, AB is not consistently associated with individual differences in body weight or drug use, AB does not consistently predict or influence distal consummatory behavior, and AB may be influenced by both appetitive and aversive motivational processes. These insights are synthesized into a theoretical account that claims that AB for food-and drug-related stimuli arises from momentary changes in evaluations of those stimuli that can be either positive (when the incentive value of the food or drug is high), negative (when individuals have a goal to change their behavior, and those stimuli are perceived as aversive), or both (when individuals experience motivational conflict, or ambivalence). Conclusions: The proposed theoretical synthesis may account for the contributions of appetitive and aversive motivational processes involved in selfregulatory conflicts to AB, and it yields testable predictions about the conditions under which AB should predict and have a causal influence on future consummatory behavior. This has implications for the prediction and modification of unhealthy behaviors and associated disorders.
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
Background: Chocolate is a naturally rewarding stimulus, it is perceived as highly problematic wi... more Background: Chocolate is a naturally rewarding stimulus, it is perceived as highly problematic with regard to controllability of its intake and appears to be one of the most craved foods. This stimulus has been reported to elicit binge eating in Eating disorders –ED. So far, very little attention has been paid to the role of food odour in the generation of craving and their associated brain functionality. Goals: The aims of the study were to compare event-related potentials of motivated attention towards chocolate stimuli (visual and smell) in binge-disordered patients when compared with healthy participants and their effect on craving. Method: 19 ED patients, diagnosed according to DSM-5 criteria, and 20 healthy controls participated in the study. All were females and performed a chocolate visual-flavours paradigm. The former consisted of 56 neutral and 56 chocolate pictures, presented in random order in a block design. Participants gave subjective ratings of craving before and after each block and electroencephalogram was recorded continuously. Results: Subjective craving towards chocolate stimuli, although increased in ED, did not differ significantly among the groups. However, there was a main effect of category in that neutral pictures with neutral smell led to the lowest craving, chocolate pictures with chocolate smell to the highest. The Late Positive Potential was higher for chocolate stimuli than for neutral stimuli, patients having lower amplitudes than healthy controls. Conclusions: Chocolate might be partially responsible for differential subjective craving effects and differences in brain activity, when comparing ED with binge episodes and healthy controls.
Journal of Behavior Therapy and Experimental Psychiatry, Mar 1, 2019
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
Objective: Although the effectiveness of interpersonal psychotherapy (IPT) and cognitive therapy ... more Objective: Although the effectiveness of interpersonal psychotherapy (IPT) and cognitive therapy (CT) for major depression has been established, little is known about how and for whom they work and how they compare in the long term. The latter is especially relevant for IPT because research on its long-term effects has been limited. This overview paper summarizes findings from a Dutch randomized controlled trial on the effects and mechanisms of change of IPT versus CT for major depression. Methods: Adult outpatients with depression (N=182) were randomly assigned to CT (N=76), IPT (N=75), or a 2-month waitlist control group followed by patient's treatment of choice (N=31). The primary outcome was depression severity. Other outcomes were quality of life, social and general psychological functioning, and scores on various mechanism measures. Interventions were compared at the end of treatment and up to 17 months follow-up. Results: On average, IPT and CT were both superior to waitlist, and their outcomes did not differ significantly from one another. However, the pathway through which change occurred appeared to differ. For a majority of participants, one of the interventions was predicted to be more beneficial than the other. No support for the theoretical models of change was found. Conclusions: Outcomes of IPT and CT did not appear to differ significantly. IPT may have an enduring effect not different from that of CT. The field would benefit from further refinement of study methods to disentangle mechanisms of change and from advances in the field of personalized medicine (i.e., person-specific analyses and treatment selection methods).
Objective: This study tested the role of habituation of eating desires and violation of overeatin... more Objective: This study tested the role of habituation of eating desires and violation of overeating expectancies during food cue exposure in obese women. Method: 52 obese females were randomised into a two-session exposure condition aimed at habituation, a twosession exposure condition aimed at expectancy violation, or a no-treatment control condition. Eating in the absence of hunger of foods included during cue exposure (i.e., exposed foods) and foods not included during cue exposure (i.e., non-exposed foods), and duration of exposure were measured. Results: Both cue exposure conditions ate significantly less of the exposed foods compared to the control condition, though there were no differences between both types of exposure. No differences were found between conditions regarding the eating of non-exposed foods. In addition, the duration of exposure was not different between both cue exposure conditions. Conclusions: While food cue exposure in obese women led to less eating of exposed foods, focusing on either habituation of eating desires or expectancy violation did not matter. It is discussed why exposure works.
UvA-DARE is a service provided by the library of the University of Amsterdam () Clinical effectiv... more UvA-DARE is a service provided by the library of the University of Amsterdam () Clinical effectiveness of cognitive therapy v. interpersonal psychotherapy for depression: results of a randomized controlled trial
The network perspective to psychopathology posits that mental disorders emerge from dynamic inter... more The network perspective to psychopathology posits that mental disorders emerge from dynamic interactions among psychopathology-relevant variables. Ecological Momentary Assessment (EMA) is frequently used to obtain measures of these variables. Currently, there is no set of EMA items available that covers the entire range of psychopathology, though there is agreement that EMA studies should go beyond single disorders in line with the transdiagnostic turn the field is taking. The current study aims to fill this gap in three steps. First, 96 clinicians were surveyed to provide three EMA constructs for up to three disorders they specialize in, as well as three EMA constructs from a transdiagnostic perspective. Second, 12 focus groups were conducted with clinical experts for specific diagnoses (e.g., mood disorders, anxiety disorders). Finally, a selection of items was made by consensus among the researchers. Two raters independently coded the online survey responses, with an inter-rater agreement of 87.3%. Jaccard indices showed up to 52.6% overlap in EMA items across diagnoses. The most frequently reported transdiagnostic constructs were mood, sleep quality, and stress. A final set of EMA items was created based on how frequently an item was mentioned and informativeness, balancing completeness across diagnoses and participant burden.
Although the effectiveness of cognitive therapy (ct) and interpersonal psychotherapy (ipt) for de... more Although the effectiveness of cognitive therapy (ct) and interpersonal psychotherapy (ipt) for depression has been well established, little is known about how, how long and for whom they work.<br/> AIM: To summarize findings from a large rct to the (differential) effects and mechanisms of change of ct/ipt for depression.<br/> METHOD: 182 adult depressed outpatients were randomized to ct (n = 76), ipt (n = 75), or a two-month wait-list-control condition (n = 31). Primary outcome was depression severity (bdi-ii). Other outcomes were quality of life, social and general psychological functioning and various potential process measures. Interventions were compared at the end of treatment, and up to 17 months follow-up.<br/> RESULTS: Overall, ct and ipt were both superior to the wait-list, but did not differ significantly from one another. However, the pathway through which therapeutic change occurred appeared to be different for ct and ipt, and many patients were predicted to have a clinically meaningful advantage in one of the two interventions. We did not find empirical support for the theoretical models of change.<br/> CONCLUSION: (Long-term) outcomes of ct and ipt appear to not differ significantly. The field would benefit from further refinement of research methods to disentangle mechanisms of change, and from advances in the field of personalized medicine.
Frontiers in Behavioral Neuroscience, Apr 21, 2020
Background: People with overweight have stronger reactivity (e.g., subjective craving) to food cu... more Background: People with overweight have stronger reactivity (e.g., subjective craving) to food cues than lean people, and this reactivity is positively associated with food intake. Cue reactivity is a learned response that can be reduced with food cue exposure therapy. Objectives: It was hypothesized that participants after food cue exposure therapy would show reduced neural activity in brain regions related to food cue reactivity and increased neural activity in brain regions related to inhibitory-control as compared to participants receiving a control lifestyle intervention. Method: Neural activity of 10 women with overweight (BMI ≥ 27 kg/m 2 ) in response to individually tailored visually presented palatable high-caloric food stimuli was examined before vs. after a cue exposure intervention (n = 5) or a control lifestyle (n = 5) intervention. Data were analyzed case-by-case. Results: Neural responses to food stimuli were reduced in food-cue-reactivity-related brain regions after the lifestyle intervention in most participants, and generally not after the cue exposure therapy. Moreover, cue exposure did not lead to increased activity in inhibitory-control-related brain regions. However, decreased neural activity after cue exposure was found in most participants in the lateral occipital complex (LOC), which suggests a decreased visual salience of high-caloric food stimuli. Receiving a cue exposure therapy did not lead to expected neural responses. As cue exposure relies on inhibitory learning mechanisms, differences in contexts (e.g., environments and food types) between the intervention setting and the scanning sessions may explain the general lack of effect of cue-exposure on neural activity.
Journal of Behavior Therapy and Experimental Psychiatry, Mar 1, 2018
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
Previous research on EMA data of mental disorders was mainly focused on multivariate regression-b... more Previous research on EMA data of mental disorders was mainly focused on multivariate regression-based approaches modeling each individual separately. This paper goes a step further towards exploring the use of non-linear interpretable machine learning (ML) models in classification problems. ML models can enhance the ability to accurately predict the occurrence of different behaviors by recognizing complicated patterns between variables in data. To evaluate this, the performance of various ensembles of trees are compared to linear models using imbalanced synthetic and real-world datasets. After examining the distributions of AUC scores in all cases, non-linear models appear to be superior to baseline linear models. Moreover, apart from personalized approaches, group-level prediction models are also likely to offer an enhanced performance. According to this, two different nomothetic approaches to integrate data of more than one individuals are examined, one using directly all data during training and one based on knowledge distillation. Interestingly, it is observed that in one of the two real-world datasets, knowledge distillation method achieves improved AUC scores (mean relative change of +17% compared to personalized) showing how it can benefit EMA data classification and performance.
In the field of psychopathology, Ecological Momentary Assessment (EMA) methodological advancement... more In the field of psychopathology, Ecological Momentary Assessment (EMA) methodological advancements have offered new opportunities to collect time-intensive, repeated and intra-individual measurements. This way, a large amount of data has become available, providing the means for further exploring mental disorders. Consequently, advanced machine learning (ML) methods are needed to understand data characteristics and uncover hidden and meaningful relationships regarding the underlying complex psychological processes. Among other uses, ML facilitates the identification of similar patterns in data of different individuals through clustering. This paper focuses on clustering multivariate time-series (MTS) data of individuals into several groups. Since clustering is an unsupervised problem, it is challenging to assess whether the resulting grouping is successful. Thus, we investigate different clustering methods based on different distance measures and assess them for the stability and quality of the derived clusters. These clustering steps are illustrated on a real-world EMA dataset, including 33 individuals and 15 variables. Through evaluation, the results of kernel-based clustering methods appear promising to identify meaningful groups in the data. So, efficient representations of EMA data play an important role in clustering.
Current Opinion in Clinical Nutrition and Metabolic Care, Nov 1, 2018
The dominant view in the literature is that increased neural reactivity to high-caloric palatable... more The dominant view in the literature is that increased neural reactivity to high-caloric palatable foods in the mesocorticolimbic system is a stable-specific characteristic of obese people. In this review, we argue that this viewpoint may not be justified, and we propose that the neural response to food stimuli is dynamic, and in synchrony with the current motivational and cognitive state of an individual. We will further motivate why a clear mental task in the scanner is a necessity for drawing conclusions from neural activity, and why multivariate approaches to functional MRI (fMRI) data-analysis may carry the field forward. From the reviewed literature we draw the conclusions that: neural food-cue reactivity depends strongly on cognitive factors such as the use of cognitive regulation strategies, task demands, and focus of attention; neural activity in the mesocorticolimbic system is not proportionate to the hedonic value of presented food stimuli; and multivariate approaches to fMRI data-analysis have shown that hedonic value can be decoded from multivoxel patterns of neural activity. Future research should take the dynamic nature of food-reward processing into account and take advantage from state-of-the-art multivariate approaches to fMRI data-analysis.
High-sugar/high-fat foods are related to binge-eating behaviour and especially people with low in... more High-sugar/high-fat foods are related to binge-eating behaviour and especially people with low inhibitory control may encounter elevated difficulties to resist their intake. Incentive sensitization to food-related cues might lead to increased motivated attention towards these stimuli and to cueinduced craving. To investigate the combined influence of olfactory and visual stimuli on craving, inhibitory control and motivated attention, 20 healthy controls and 19 individuals with binge-eating viewed chocolate and neutral pictures, primed by chocolate or neutral odours. Subjective craving and electroencephalogram activity were recorded during the task. N2 and Late Positive Potential (LPP) amplitudes were analysed. Patients reported higher craving than controls. Subjective craving, N2 and LPP amplitudes were higher for chocolate versus neutral pictures. Patients showed a higher relative increase in N2 amplitudes to chocolate versus neutral pictures than controls. Chocolate images induced significant increases in craving, motivated attention and measures of cognitive control. Chocolate odour might potentiate the craving response to visual stimuli, especially in patients with binge-eating.
Brain responses to food are thought to reflect food’s rewarding value. We propose that brain resp... more Brain responses to food are thought to reflect food’s rewarding value. We propose that brain responses to food are more dynamic and hypothesize that brain responses to food depend on attentional focus. Food pictures (high-caloric/low-caloric, palatable/unpalatable) were presented during fMRI-scanning, while attentional focus (hedonic/health/neutral) was induced in 52 female participants varying in dietary restraint. The level of brain activity was hardly different between palatable versus unpalatable foods or high-caloric versus low-caloric foods. Activity in several brain regions was higher in hedonic than in health or neutral attentional focus (p &lt; 0.05, FWE-corrected). Palatability and calorie content could be decoded from multi-voxel activity patterns (p &lt; 0.05, FDR-corrected). Dietary restraint did not significantly influence brain responses to food. So, level of brain activity in response to food stimuli depends on attentional focus, and may reflect salience, not reward value. Palatability and calorie content are reflected in patterns of brain activity.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Behavior Therapy and Experimental Psychiatry, Jun 1, 2020
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
The purpose of this article is to critically evaluate the following claims derived from contempor... more The purpose of this article is to critically evaluate the following claims derived from contemporary theoretical models of attentional bias (AB) for food-and drug-related stimuli: (a) AB is a characteristic feature of obesity and addiction, (b) AB predicts future behavior, (c) AB exerts a causal influence on consummatory behavior, and (d) AB reflects appetitive motivational processes. Method: A focused discussion of the relevant literature is presented. Results: The available evidence reveals inconsistencies with the aforementioned claims. Specifically, AB is not consistently associated with individual differences in body weight or drug use, AB does not consistently predict or influence distal consummatory behavior, and AB may be influenced by both appetitive and aversive motivational processes. These insights are synthesized into a theoretical account that claims that AB for food-and drug-related stimuli arises from momentary changes in evaluations of those stimuli that can be either positive (when the incentive value of the food or drug is high), negative (when individuals have a goal to change their behavior, and those stimuli are perceived as aversive), or both (when individuals experience motivational conflict, or ambivalence). Conclusions: The proposed theoretical synthesis may account for the contributions of appetitive and aversive motivational processes involved in selfregulatory conflicts to AB, and it yields testable predictions about the conditions under which AB should predict and have a causal influence on future consummatory behavior. This has implications for the prediction and modification of unhealthy behaviors and associated disorders.
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
Background: Chocolate is a naturally rewarding stimulus, it is perceived as highly problematic wi... more Background: Chocolate is a naturally rewarding stimulus, it is perceived as highly problematic with regard to controllability of its intake and appears to be one of the most craved foods. This stimulus has been reported to elicit binge eating in Eating disorders –ED. So far, very little attention has been paid to the role of food odour in the generation of craving and their associated brain functionality. Goals: The aims of the study were to compare event-related potentials of motivated attention towards chocolate stimuli (visual and smell) in binge-disordered patients when compared with healthy participants and their effect on craving. Method: 19 ED patients, diagnosed according to DSM-5 criteria, and 20 healthy controls participated in the study. All were females and performed a chocolate visual-flavours paradigm. The former consisted of 56 neutral and 56 chocolate pictures, presented in random order in a block design. Participants gave subjective ratings of craving before and after each block and electroencephalogram was recorded continuously. Results: Subjective craving towards chocolate stimuli, although increased in ED, did not differ significantly among the groups. However, there was a main effect of category in that neutral pictures with neutral smell led to the lowest craving, chocolate pictures with chocolate smell to the highest. The Late Positive Potential was higher for chocolate stimuli than for neutral stimuli, patients having lower amplitudes than healthy controls. Conclusions: Chocolate might be partially responsible for differential subjective craving effects and differences in brain activity, when comparing ED with binge episodes and healthy controls.
Journal of Behavior Therapy and Experimental Psychiatry, Mar 1, 2019
or visit the DOI to the publisher's website. • The final author version and the galley proof are ... more or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User
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Papers by Anne Roefs