Table 2.

Clinical characteristics of included patients and methodological features of studies included in the multilevel meta-analysis.

Characteristic	Placebo-Controlled Studies	Comparator Studies
N studies	62	49
N medication treatment groups	126	99
N patients in medication treatment groups	13,676	8,734
N placebo treatment groups	62	0
N patients in placebo treatment groups	6,750	0
Mean age	41.1 ± 2.5	42.1 ± 3.5
Mean drop-out rate	31.8 ± 14.1	24.0 ± 10.2
Mean N ITTa	108.9 ± 56.7	88.2 ± 52.3
Mean pre-treatment HRSDb	24.6 ± 3.6	26.1 ± 4.8

	N treatment conditions	N patients	N treatment conditions	N patients
Study duration
6 wks	77	5,999	55	3,592
8 wks	92	12,169	36	4,218
12 wks	4	503	8	924
Study visits
Weekly	66	4,750	20	1,148
Skip 1 visit	29	3,146	4	589
Skip 2 visits	55	8,088	32	2,611
Skip ≥3 visits	45	4,369	35	3,748
Meds used
SSRIc	53	5,812	54	4,986
SNRId	40	4,700	15	1,762
TCAe	16	1,096	12	733
Atypical ADf	15	1,835	17	1,230
MAOIg	2	233	1	23

^aITT = Intent to treat

^bHRSD = Hamilton Rating Scale for Depression

^cSSRI = Selective Serotonin Reuptake Inhibitor

^dSNRI = Serotonin Norepinephrine Reuptake Inhibitor

^eTCA = Tricyclic antidepressant

^fAtypical AD = Atypical antidepressant (e.g., bupropion, nefazodone, mirtazipine, trazodone)

^gMAOI = Monoamine Oxidase Inhibitor