Adherence as a determinant of effectiveness of internet cognitive behavioural therapy for anxiety and depressive disorders.

Since 2009, the Clinical Research Unit for Anxiety and Depression (CRUfAD) has been providing primary care clinicians with internet cognitive behaviour therapy (iCBT) courses to prescribe to patients. Although these courses have demonstrated efficacy in research trials, adherence in primary care is less than half that of the research trials. The present studies pose three questions: first, do course non-completers drop out because of lack of efficacy? Second, can changes in delivery (e.g. adding choice, reminders and financial cost) improve adherence? Last, does clinician contact improve adherence? The results showed that non-completers derive benefit before dropping out; that adding reminders, choice of course and timing, and financial cost can significantly improve adherence; and that clinician contact during the course is associated with increased adherence. It is concluded that improved adherence is an important determinant of effectiveness.