Table 2.

Odds ratios (with 95 % confidence interval) for substance use-related problems in ASD probands compared to matched non-ASD controls

Substance-related problem	Bivariate analysis				Multivariate analysisa
	Comorbidity				Comorbidity
	None	ADHD	ID	ADHD + ID	None	ADHD	ID	ADHD + ID
	Crude OR (95 % CI)	Crude OR (95 % CI)	Crude OR (95 % CI)	Crude OR (95 % CI)	Adjusted OR (95 % CI)	Adjusted OR (95 % CI)	Adjusted OR (95 % CI)	Adjusted OR (95 % CI)
Any problem	2.6 (2.4–2.9)***	8.3 (7.4–9.2)***	1.1 (0.9–1.3)	4.6 (3.7–5.8)***	2.2 (2.0-2.4)***	5.0 (4.5–5.6)***	1.0 (0.8–1.2)	3.3 (2.7–4.1)***
Substance use disorder	4.0 (3.6–4.5)***	12.4 (11.0-13.8)***	1.8 (1.4–2.2)***	7.4 (5.9–9.4)***	3.2 (2.9–3.6)***	7.2 (6.4–8.1)***	1.6 (1.3-2.0)***	5.3 (4.2–6.7)***
Alcohol	3.3 (2.9–3.8)***	8.2 (7.1–9.5)***	1.6 (1.2–2.1)***	6.1 (4.6–8.1)***	2.7 (2.4–3.1)***	5.0 (4.3–5.6)***	1.5 (1.2–1.9)**	4.6 (3.5–6.1)***
Drugs	6.0 (5.2-7.0)***	23.6 (20.3–27.3)***	2.5 (1.8–3.4)***	10.7 (7.9–14.6)***	4.4 (3.7–5.1)***	11.7 (10.0-13.7)***	2.2 (1.6-3.0)***	7.0 (5.1–9.6)***
Tobacco	2.4 (0.7–7.6)	15.8 (7.7–32.3)***	5.8 (1.7–19.1)***	3.8 (0.5–29.4)	2.0 (0.6–6.3)	7.4 (3.4–16.1)***	5.4 (1.6–17.7)**	2.8 (0.4–22.1)
Crime	1.0 (0.8–1.2)	4.0 (3.3–4.8)***	0.2 (0.1–0.4)***	1.4 (0.9–2.3)	0.9 (0.7–1.1)	2.6 (2.2–3.1)***	0.2 (0.1–0.3)***	1.1 (0.7–1.7)
Death	3.2 (1.0-10.3)	5.3 (1.2–22.6)*	–b	7.1 (0.9–58.1)	2.5 (0.8–8.2)	–b	–b	–b
Somatic disease	3.6 (0.9–15.0)	2.9 (0.4–22.1)	10.0 (2.2–45.6)**	25.0 (4.6 − 136.5)***	2.9 (0.7–12.3)	–b	–b	–b

Results stratified by comorbidity

ADHD attention deficit hyperactivity disorder, ID intellectual disability

*p value <0.05;**p value <0.01; ***p value <0.001

^aAdjustment for parental education, family income and substance use disorder prior to ASD diagnosis

^bOR and 95 % CI were not calculable due to no observations