A pragmatic patient preference trial of cognitive behavioural versus cognitive analytic guided self-help for anxiety disorders

Aims:

To outline the methods of a pragmatic patient preference trial in the Improving Access to Psychological Therapies (IAPT) programme comparing cognitive behavioural therapy guided self-help (CBT-GSH) with cognitive analytic therapy guided self-help (CAT-GSH).

Method:

A partially randomised patient preference trial (PRPPT) methodology. Participants will be assessed with the MINI to ascertain a diagnosis of an anxiety disorder. Treatment will be six to eight 35-minute sessions in each arm. The primary outcome measure is the Beck Anxiety Inventory (BAI), with secondary outcome measures of the IAPT minimum dataset and indices of service utilisation. Participants will be followed up at 8 and 24 weeks.

Planned analyses:

Choice, treatment completion, drop-out and step-up rates will be summarised via a CONSORT diagram. If there are no differences between randomised and preference participants within each form of GSH, then these groups will be collapsed to form a two-arm trial. The primary analysis will compare between-arm standardised effect sizes on the BAI measure, using Cohen’s d+ at 8- and 24-week follow-up. The proportions in each arm achieving reliable and clinical change on the BAI will be established, with interviews exploring the change process with participants achieving a reliable pre–post change on the GAD-7.

Conclusions:

The utility of patient preference trials in mental health services are discussed and the necessary further development of robust evidence concerning low-intensity interventions is highlighted.