Table 3.

Results from multivariate meta-regression for the impact of placebo-controlled trials in response and dropout with active antidepressant drugs. Results are adjusted for the type of antidepressant. Heterogeneity standard deviations did not differ materially across models (less than 1% change) and were τ = 0.20 (response), τ = 0.36 (all-cause dropout), τ = 0.43 (dropout due to adverse events)

	Response to active treatment	All-cause dropout	Dropout due to adverse events
Number of active arms (studies)	647 (386)	641 (378)	580 (350)
Risk ratios (95% CI): π = 0%	1	1	1
π >0%	0.87 (0.83, 0.92)	1.19 (1.08, 1.31)	1.07 (0.94, 1.23)
π = 0%	1	1	1
20%≤π<50%	0.88 (0.83, 0.93)	1.19 (1.08, 1.31)	0.98 (0.78, 1.22)
π = 50%	0.84 (0.77, 0.92)	1.15 (0.99, 1.34)	1.08 (0.94, 1.25)
for π increase by 10%	0.97 (0.95, 0.98)	1.04 (1.01, 1.07)	1.06 (0.73, 1.56)

π, probability of being allocated to placebo arm.