Background: There is substantial evidence that early improvement (EI) under antidepressant treatment is a clinically useful predictor of later treatment outcome in patients with major depressive disorders. The aim of this study was to test whether EI can also be used as a predictor for treatment outcome in patients with mild major, minor or subsyndromal depression, i.e. patients, who are typically treated by general practitioners.
Methods: Analyses were carried out using data from 223 patients of a 10-weeks randomized, placebo-controlled trial comparing the effectiveness of sertraline and cognitive-behavioural therapy (CBT) in patients with mild major, minor or subsyndromal depression. EI was defined as a reduction of > or =20% on the 17-item Hamilton Rating Scale for Depression (HAMD-17) compared with baseline within the first 2 weeks of treatment. The predictive value of EI for stable response at week 8 and 10 (> or =50% HAMD-17 sum score reduction at weeks 8 and 10) and stable remission (HAMD-17 sum score < or =7 at weeks 8 and 10) was evaluated.
Results: In both the sertraline- and CBT-treatment group, EI was a highly sensitive predictor for later stable response (76% and 82%, respectively) and stable remission (70% and 75%, respectively). In patients without EI, only a small proportion of sertraline or CBT-treated patients achieved stable response (20.9% and 5.9%, respectively) or stable remission (18.6% and 8.8%, respectively). Patients with EI were by far more likely to achieve stable response or stable remission than patients without as indicated by high odds ratios (95% confidence interval) of 8.1 (3.0-21.8) and 3.8 (1.4-10.1) for sertraline, and 11.1 (2.1-58.4) and 7.2 (1.7-30.8) for CBT-treated patients, respectively.
Limitations: Sample sizes were relatively low in different treatment groups.
Conclusion: The identification of early improvement might be useful in clinical decision making in the early course of treatment of patients with mild major, minor and subthreshold depression.