Moderators of remission with interpersonal counselling or drug treatment in primary care patients with depression: randomised controlled trial

BACKGROUND: Despite depressive disorders being very common there has been little research to guide primary care physicians on the choice of treatment for patients with mild to moderate depression.
AIMS: To evaluate the efficacy of interpersonal counselling compared with selective serotonin reuptake inhibitors (SSRIs), in primary care attenders with major depression and to identify moderators of treatment outcome.
METHOD: A randomised controlled trial in nine centres (DEPICS, Australian New Zealand Clinical Trials Registry number: ACTRN12608000479303). The primary outcome was remission of the depressive episode (defined as a Hamilton Rating Scale for Depression score ≤7 at 2 months). Daily functioning was assessed using the Work and Social Adjustment Scale. Logistic regression models were used to identify moderators of treatment outcome.
RESULTS: The percentage of patients who achieved remission at 2 months was significantly higher in the interpersonal counselling group compared with the SSRI group (58.7% v. 45.1%, P = 0.021). Five moderators of treatment outcome were found: depression severity, functional impairment, anxiety comorbidity, previous depressive episodes and smoking habit.
CONCLUSIONS: We identified some patient characteristics predicting a differential outcome with pharmacological and psychological interventions. Should our results be confirmed in future studies, these characteristics will help clinicians to define criteria for first-line treatment of depression targeted to patients' characteristics.