Table 3.

 Crude and adjusted odds ratios with 95% confidence intervals (95% CI) for developing schizophrenia in years 0-5 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†	5320	33 (0.6)	2.2 (1.7 to 2.8)	2.1 (1.2 to 3.7)
Frequency of use of cannabis (ever):
None	36 429	47 (0.1)	1.0†	1.0†
Once	608	0	—	—
2-4 times	1380	2 (0.1)	1.1 (0.3 to 4.6)	1.0 (0.2 to 4.4)
5-10 times	806	4 (0.5)	3.9 (1.4 to 10.7)	2.6 (0.8 to 7.9)
11-50 times	689	4 (0.6)	4.5 (1.6 to 12.6)	2.8 (0.9 to 8.8)
>50 times	731	13 (1.8)	14.0 (7.5 to 26.0)	4.7 (1.8 to 12.4)
Linear trend for frequency of use		—	1.6 (1.4 to 1.8)	1.3 (1.1 to 1.6)

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

^†No drug use as baseline comparison.