Table 3.

Correlates of transition to drug co-use and number of drugs other than cannabis (DOTC) co-used. Results of bivariate and multivariable Poisson regression models (n = 118).

Characteristics	Rate of progression to drug co-use		Number of DOTC co-used
	IRR (95%CI)	AIRR^a (95%CI)	IRR (95%CI)	AIRR^a (95%CI)
Mental health disorder symptoms
Anxiety disorder symptoms	0.98 (0.93; 1.03)	0.98 (0.93; 1.04)	1.00 (0.97; 1.03)	0.97 (0.93; 1.01)
Mood disorder symptoms	0.98 (0.96; 1.00)	0.98 (0.95; 1.01)	1.01 (0.99; 1.03)	1.02 (0.99; 1.06)
Externalized disorder symptoms	1.00 (0.99; 1.03)	1.01 (0.98; 1.04)	1.00 (0.99; 1.02)	0.99 (0.98; 1.02)
Decision-making task
IGT total net	1.00 (0.99; 1.01)	1.01 (1.01; 1.03) ^*	1.00 (0.99; 1.01)	1.01 (0.99; 1.02)
Cannabis use-related factors
Number of cannabis use problems	0.98 (0.94; 1.02)	0.99 (0.96; 1.02)	1.03 (1.01; 1.04) ^**	1.03 (1.01; 1.05) ^**

Notes: IRR = Incidence Rate Ratios.

Past-year anxiety disorder symptoms include any symptoms for panic disorder, generalized anxiety disorder and obsessive-compulsive disorder during the year prior to assessment based on the CDISC-IV. Past-year mood disorder symptoms include any symptoms for major depressive episode and maniac episode during the year prior to assessment based on the CDISC-IV. Past-year externalizing disorder symptoms include symptoms for attention deficit disorder, oppositional defiant disorder, and conduct disorder during the year prior to assessment based on the CDISC-IV.

Bold indicates significant p-values.

Adjusted Incidence Rate Ratios (AIRR), adjusted models include all covariates in the table plus the variables sex, centered age², centered age of cannabis use onset², WRAT-4 standardized reading score, amount of alcohol use in the lifetime, amount of tobacco use in the lifetime, amount of cannabis use in the lifetime, and number of days since last cannabis use.

p-value < 0.05.

^**

p-value < 0.01.