Randomized Trial of Treatment of Depression With Interpersonal Psychotherapy and Cognitive Behavioral Therapy

The main purpose of the study is to analyze whether Interpersonal psychotherapy (IPT) and Cognitive Behavioural Therapy (CBT) are effective psychotherapies for depressed patients, with respect to changes in working capacity and psychiatric diagnosis. A secondary purpose is to study moderating factors in the two methods. The study has a randomized design. It will be performed at the Psychiatric Clinic in Sundsvall.

The differences in effect between different forms of psychotherapy for depression, when reduction in symptoms is used as outcome criterion, are rather small. In a recent meta-analysis, differences in efficacy between seven forms of psychotherapy were compared (Cuijpers, van Straten, Andersson & van Oppen, 2008). The efficacy was on the whole the same.

In the guidelines from National Board of Health and Welfare in Sweden, CBT and IPT are recommended as the first hand choices for treatment of mild and moderate depression. This recommendation is based on studies from other countries. Comparative randomized studies of CBT and IPT have not been published in Sweden.

Hypotheses The main hypotheses in this study is that CBT and IPT are both effective treatments for Major Depressive Disorder, and that they have equal effects with regard to remission from depression, but that CBT is more effective than IPT when return to employment is the outcome measure. Three moderator hypotheses will be tested. The first moderator hypothesis is that patients with attachment avoidance get better results with CBT, whereas patients with attachment anxiety get better results with IPT. The second hypothesis is that patients with higher RF get better results with IPT than with CBT. The third moderator hypothesis is that women respond better to IPT and men to CBT, particularly if relational functioning is considered. In the moderator hypotheses, both remission from depression and return to work will be outcome criteria.

Method Participants Patients who seek treatment with the diagnosis Major Depressive Disorder (MDD), and who indicate mild or moderate depression on Beck's Depression Inventory will be asked to participate. The inclusion criterion is thus Major depressive disorder with mild or moderate severity. Exclusion criteria are psychosis, ongoing drug abuse, serious neuropsychiatric disorder, personality disorder cluster B. Patients with severe depression will also be excluded. We will also exclude patients who have used the disability pension and only include patients who have sickness benefit, as it is improbable the psychotherapy with 14 sessions will be enough for patients with disability pension. There will be no treatment arm with only medication. Ongoing medication is no obstacle for participation, but changes in medication will be avoided if possible. Medication will be registered. The patients will be randomized to the treatment alternatives. In all, 96 patients will take part in the study.