A Randomized Controlled Trial of Cognitive Behavioural Therapy as an Adjunct to Pharmacotherapy in Primary Care Based Patients with Treatment Resistant Depression: A Pilot Study

No randomized controlled trials (RCTs) have been conducted of cognitive behavioural therapy (CBT) for depressed patients who have not responded to antidepressants, yet CBT is often reserved for this group. We conducted a pilot study for a pragmatic RCT of the clinical effectiveness of CBT as an adjunct to pharmacotherapy in primary care based patients with treatment resistant depression (TRD). Patients on antidepressants for at least 6 weeks were mailed a study invitation by their GP. Those who consented to contact were mailed a questionnaire. TRD was defined as compliance with medication (self-report) and Beck Depression Inventory (BDI) ≥ 15. Those who met ICD-10 depression criteria were eligible for randomization and followed after 4 months. Of 440 patients mailed, 65% responded and 72% consented to contact. Ninety-four percent completed the questionnaire and 82 patients (42%) had TRD. Thirty were subsequently identified as ineligible and 10 did not participate further. Twenty-six of the remaining 42 patients met ICD-10 depression criteria and 25 agreed to being randomized. Twenty-three patients completed the 4-month follow-up questionnaire. Recruitment into a RCT to examine the effectiveness of CBT as an adjunct to pharmacotherapy in primary care based patients with TRD appears feasible and should now be conducted.