. Author manuscript; available in PMC: 2018 Feb 1.

Published in final edited form as: J Am Acad Child Adolesc Psychiatry. 2016 Nov 25;56(2):149–156. doi: 10.1016/j.jaac.2016.11.004

Table 4.

Interval Censored Proportional Hazards Survival Analysis of Drug Use

	Any Drug Use (n=669)			Regular Drug Use (n=429)^a

	HR	95% CI	p-val	HR	95% CI	p-val
Parental marital status
Remarried/living with a partner	1.58	0.94, 2.66	.003^b	3.99	1.58, 10.09	.01
Separated/divorced/widowed	1.29	0.79, 2.10		2.86	1.14, 7.16
Single	2.37	1.47, 3.80		4.49	1.80, 11.20
Parental history of substance abuse	1.70	1.19, 2.43	.004	n/a
Number of impactful stressful life events (per 1-event increase)	1.05	1.01, 1.09	.006	1.11	1.05, 1.17	<.001
Primary baseline diagnosis of DBD	n/a			2.41	1.35, 4.30	.003
Number of medications at baseline (per each additional medication)	n/a			0.67	0.50, 0.91	.01

Note: Reference for parental marital status is married to biological parent. n/a indicates that variable was not statistically significant at p<.05 and was omitted from the model. DBD = disruptive behavior disorder; HR = hazard ratio.

Regular drug use is unknown prior to high school; thus, the sample includes those who participated in Longitudinal Assessment of Manic Symptoms Study during high school.

Any drug use: single vs. separated/divorced/widowed: HR=1.83, 95% CI: 1.16, 2.89.