Table 2.

Frequency of most common first and primary substances of use by most common psychopathology diagnoses

	First substance of use
Psychopathology	Cannabis	p-value†	Crystal Methamphetamine	p-value†
Conduct disorder	38 (59.3)	0.048	11 (17.2)	0.782
Anti-social personality disorder	46 (55.4)	0.065	14 (16.9)	0.445
Major depression	14 (58.3)	0.486	2 (8.3)	0.223
Oppositional defiant disorder	20 (62.5)	0.192	4 (12.5)	0.405
	Most common primary substance of use
	Heroin	p-value†	Crystal Methamphetamine	p-value†
Conduct disorder	19 (29.7)	0.170	15 (23.4)	0.592
Anti-social personality disorder	29 (34.9)	1.000	16 (19.3)	0.271
Major depression	8 (33.3)	1.000	3 (12.5)	0.385
Oppositional defiant disorder	9 (28.1)	0.371	10 (31.1)	0.111

^†Chi-squared testing when expected frequencies >5 and Fisher's Exact testing when expected frequencies <5