Background. Little is known about how continuation and maintenance cognitive-behavioural therapy (CBT) influences important psychological constructs that may be associated with long-term outcome of major depressive disorder. The goal of this study was to examine whether CBT would help maintain attributional style changes experienced by patients during acute phase fluoxetine treatment.

Method. Three hundred and ninety-one patients with major depressive disorder were enrolled in an open, fixed-dose 8 week fluoxetine trial. Remitters to this acute phase treatment (N=132) were randomized to receive either fixed-dose fluoxetine (meds only) or fixed-dose fluoxetine plus cognitive-behavioural therapy (CBT+meds) during a 6-month continuation treatment phase. The Attributional Style Questionnaire (ASQ) was completed by patients at three time points – acute phase baseline, continuation phase baseline and continuation phase endpoint. Analysis of covariance was used to compare continuation phase ASQ composite score changes between groups.

Results. Patients in both treatment groups experienced significant gains in positive attributional style during the acute phase of treatment. Continuation phase ASQ composite change scores differed significantly between treatment groups, with the CBT+meds group maintaining acute phase positive attributional style changes, and the meds only group exhibiting a worsening of attributional style. The two treatment groups did not significantly differ in rates of relapse and final continuation phase visit HAMD-17 scores.

Conclusions. In this sample, the addition of CBT to continuation psychopharmacological treatment was associated with maintenance of acute treatment phase attributional style gains. Further research is needed to evaluate the role of such gains in the long-term course of depressive illness.