Participants were recruited to the CoBalT study through 73 GP practices in Bristol, Exeter, and Glasgow and surrounding areas. Eligible patients were those aged 18–75 years, currently taking antidepressants, who had done so for at least 6 weeks at an adequate dose, and who had adhered to their medication, had a Beck Depression Inventory (BDI)29 score of >13, and met International Classification of Diseases (ICD)-10 criteria for depression assessed using the Clinical Interview Schedule — revised version.30
How this fits in
Particular difficulties are reported in relation to recruiting primary care patients into mental health trials but little is known about why people do not take part in research. Using a mixed-methods approach, this study identified patients' reasons for declining contact in a study about the effectiveness of cognitive-behavioural therapy for treatment-resistant depression. Patients declined due to: previous negative experiences of talking therapy; misgivings about the therapeutic encounter because they considered themselves ineligible or misunderstood the treatment intervention. These concerns, if identified, could be addressed by the research team or GP, to improve recruitment to studies.