Table 1.

Association of depression with substance-related behaviors.

	k	r	CI		t	Q
Depression—current drug use and impairment	25	0.10	0.07	0.14	5.91*	52.29*
Depression—current alcohol use and impairment	7	0.08	0.04	0.12	4.22*	6.66
Depression—future drug use and impairment	15	0.01	−0.05	0.07	0.48	43.27*
Depression—treatment participation	18	0.06	0.04	0.09	4.59*	22.96
Depression—needle sharing	13	0.11	0.08	0.14	8.23*	15.86

k: number of studies, r: correlation coefficient, CI: 95% confidence interval, t: test for significance of the mean effect size, Q: test for heterogeneity of effect sizes (significant values indicate heterogeneity).

^*P < 0.001.