Table 1

Multivariable logistic regression analysis of clinical and demographic factors and history of cannabis use at presentation with first episode psychosis (n=2026)

Factor	Number in sample	Percentage with history of cannabis use (%)	Univariate analysis OR (95% CI), p value	*Multivariable analysis OR (95% CI), p value
Age <16 years	19	10.5	0.11 (0.03 to 0.48), p=0.003	0.12 (0.03 to 0.53), p=0.005
Age 16–25 years	1234	51.7	Reference	Reference
Age 26–35 years	747	39.0	0.60 (0.50 to 0.72), p<0.001	0.70 (0.57 to 0.85), p=0.017
Age >35 years	26	30.8	0.42 (0.18 to 0.96), p=0.04	0.48 (0.20 to 1.14), p=0.006
Female	731	30.5	0.35 (0.29 to 0.43), p<0.001	0.39 (0.32 to 0.48), p<0.001
Male	1295	55.3	Reference	Reference
White	616	49.8	1.21 (0.99 to 1.48), p=0.06	1.17 (0.95 to 1.45), p=0.15
Asian	126	38.9	0.78 (0.53 to 1.13), p=0.19	0.84 (0.56 to 1.25), p=0.38
Black	1005	45.1	Reference	Reference
Other	279	46.6	1.06 (0.81 to 1.39), p=0.65	1.13 (0.84 to 1.50), p=0.42
Married/cohabiting	153	28.8	0.41 (0.28 to 0.59), p<0.001	0.56 (0.38 to 0.82), p=0.003
Divorced/separated	63	23.9	0.32 (0.18 to 0.57), p<0.001	0.47 (0.26 to 0.87), p=0.02
Single	1727	49.4	Reference	Reference
Marital status not recorded	83	31.3	0.47 (0.29 to 0.75), p=0.002	0.50 (0.30 to 0.82), p=0.006
Schizophrenia and related	1097	48.4	Reference	Reference
Bipolar disorder	100	52.0	1.15 (0.77 to 1.74, p=0.49)	1.44 (0.93 to 2.22), p=0.10
Psychotic depression	94	30.9	0.48 (0.30 to 0.75, p=0.001)	0.56 (0.35 to 0.90), p=0.02
Schizoaffective disorder	35	34.2	0.56 (0.27 to 1.13, p=0.10)	0.72 (0.35 to 1.51), p=0.39
Drug-induced psychosis	63	79.0	4.10 (0.62 to 0.92, p<0.001)	3.12 (1.64 to 5.88), p<0.001
Other psychotic disorder	637	41.6	0.76 (0.62 to 0.92, p=0.006)	0.79 (0.64 to 0.97), p=0.02

*Multivariable analysis adjusted for all factors presented in table (and no others).