Table 2.

 Crude and adjusted odds ratios with 95% confidence intervals for developing schizophrenia any time after conscription in subjects who have ever used cannabis

Drug use	No of subjects	No (%) of subjects developing schizophrenia	Odds ratio (95% CI)
			Crude	Adjusted*
Cannabis ever†	5391	73 (1.4)	2.2 (1.7 to 2.8)	1.5 (1.1 to 2.0)
Frequency of use of cannabis (ever):
None	36 429	215 (0.6)	1.0†	1.0†
Once	608	2 (0.3)	0.6 (0.1 to 2.2)	0.6 (0.1 to 2.3)
2-4 times	1380	8 (0.6)	1.0 (0.5 to 2.0)	0.9 (0.4 to 1.9)
5-10 times	806	9 (1.1)	1.9 (1.0 to 3.7)	1.4 (0.7 to 2.8)
11-50 times	689	13 (1.9)	3.2 (1.8 to 5.7)	2.2 (1.2 to 4.0)
>50 times	731	28 (3.8)	6.7 (4.5 to 10.0)	3.1 (1.7 to 5.5)
Linear trend for frequency of use	—	—	1.4 (1.3 to 1.5)	1.2 (1.1 to 1.4)

^*Adjusted for diagnosis at conscription to IQ score to poor social integration to disturbed behaviour to cigarette smoking to and place of upbringing. 

^†No drug use as baseline comparison.