Jass, who lives in Levenshulme, Greater Manchester, said: "When the medication shortage started I had to go back to white knuckling everyday life… I had to take the decision to change things and I had to quit the job I was doing."

Former charity worker Jass has been without her prescription for six months and told the BBC it had exacerbated her fibromyalgia, a long-term condition that causes pain all over her body.

Dr Morgan Toerien, associate specialist in mental health at Beyond Clinics in Warrington, said Jass's experience was not unique and many patients' lives had been "completely destabilised".

Jass told the BBC her medication made her feel "free" and "independent".

But the 34-year-old's joy was short-lived because, like more than 150,000 others who live with the condition and are reliant on medication, Jass has been affected by a UK-wide medicine shortage that started in September.