Table 2

Meta-analyses of studies examining effects of psychological treatment of depression in primary care compared to control conditions at post-test: overall results and subgroup analyses.^a

	n_studies	n_comp	d	95% CI	Z	Q	I²	P-value^g	NNT

All studies	20	20	0.31	0.17 to 0.45	4.25^d	34.91^b	45.58		5.75

One effect per study (highest)	15	15	0.30	0.13 to 0.48	3.47^c	30.35^c	53.88		5.95

One effect per study (lowest)	15	15	0.25	0.09 to 0.41	3.10^c	27.08^b	48.30		7.14

BDI only	10	14	0.43	0.22 to 0.64	4.07^d	26.30^b	50.57		4.20

HAM-D only	7	7	0.49	0.30 to 0.68	5.11^d	5.34, ns	0		3.68

Subgroup analyses

Recruitment^f
Referral	7	11	0.43	0.28 to 0.58	5.75^d	9.71, ns	0	b	4.20
Screening	6	7	0.13	−0.08 to 0.34	1.23	9.82, ns	38.89		13.51

Diagnosis
MDD	7	10	0.21	−0.00 to 0.42	1.95^e	19.15^b	53.00	ns	8.47
Other	7	10	0.40	0.23 to 0.56	4.61^d	11.12, ns	19.09		4.50

Type of treatment^h
CBT	7	9	0.42	0.22 to 0.62	4.16^d	9.72, ns	17.67	ns	4.27
PST	5	5	0.19	−0.15 to 0.53	1.08, ns	9.77^b	59.05		9.43
Other	5	6	0.27	0.04 to 0.49	2.35^b	9.65^e	48.20		6.58

Number of sessions^h
≤6	7	9	0.25	0.02 to 0.48	2.12^b	16.56^b	51.68	ns	7.14
≥7	8	11	0.36	0.17 to 0.54	3.75^d	17.34^e	42.34		5.00

Control group
Care-as-usual	10	13	0.29	0.14 to 0.43	3.87^d	15.88, ns	24.45	ns	6.17
Other	5	7	0.40	0.07 to 0.73	2.39^b	18.73^c	67.97		4.50

Analyses
Intention-to-treat	10	10	0.23	0.05 to 0.42	2.47^b	23.18^c	61.18	e	7.69
Completers-only	5	10	0.47	0.27 to 0.68	4.48^d	6.53, ns	0		3.85

Country
UK	8	12	0.45	0.28 to 0.62	5.19^d	15.09, ns	27.09	b	4.00
US	5	6	0.11	−0.15 to 0.38	0.84, ns	10.01^e	50.03		16.13
NL	2	2	0.10	−0.15 to 0.35	0.81, ns	0.50, ns	0		17.86

↵a According to the random effects model.
↵b P<0.05.
↵c P<0.01.
↵d P<0.001.
↵e P<0.1.
↵f In two studies information about how patients were screened was insufficient.
↵g The P-value indicates whether the difference between subgroups is significant.
↵h The total number of studies is larger than 15 because some studies examined more than one type of psychothery.
n_comp = number of comparisons. d = standardised mean difference. Q = indicator of homogeneity. I² = indicator of heterogeneity in percentages. NNT = numbers-needed-to-treat. BD I = Beck Depression Inventory. HAM-D = Hamilton Rating Scale for Depression. MDD = major depressive disorder. CBT = cognitive behavioural therapy. PST = problem solving therapy. NL = the Netherlands.