Seven randomised controlled trials (RCTs) were included in the meta-analysis (n=903 participants). Six trials focused on non-chronic depression, whilst one trial investigated chronic depression. Three trials were of mild depression. Four trials were of moderate depression.
Whilst drop-out rates across the trials ranged from 18 to 36%, pooled drop-out rates for combined therapy (psychotherapy with pharmacotherapy) and psychotherapy alone did not differ statistically. There was no evidence of statistical heterogeneity for this outcome.
The pooled remission rate for combined therapy (46%) was statistically significantly higher than for psychotherapy (34%) (relative risk 1.32, 95% confidence interval: 1.12 to 1.56). There was no evidence of statistical heterogeneity. Based on one trial of patients with chronic depression, remission rates of combined therapy were statistically significantly better than with psychotherapy (48% versus 32%, p<001). In moderate depression, the pooled remission rates were also better with combined therapy (47% versus 34%, p=0.001). In non-chronic depression and in mild depression the pooled remission rates of psychotherapy and combined therapy did not differ significantly.
Further subgroup analyses were presented in the paper.