Substance use in youth at-risk for serious mental illness

Aim The aim of this paper is to describe the substance use of participants who are at-risk for serious mental illness (SMI). Method The Canadian Psychiatric Risk and Outcome study (PROCAN) is a two-site study of 243 youth and young adults aged 13 to 25 years, categorized into four groups: healthy controls (n = 42), stage 0 (asymptomatic individuals with risk of SMI typically family high risk; n = 41), stage 1a (distress disorder or mild symptoms of anxiety or depression; n = 53) and stage 1b (attenuated syndromes, including bipolar disorder or psychosis; n = 107). Substance use measures were administered at baseline, 6- and 12-months. Results At baseline, the most commonly reported substance used in the past month was alcohol (43.6%), followed by cannabis (14.4%) and tobacco (12.4%). There were no significant group differences in use. 42.4% of all participants reported ever using cannabis in their lifetime, whereas 21.4% reported currently using cannabis. There were no group differences in ever having used cannabis. Regarding lifetime substance abuse disorders, cannabis use disorder (5.7%) and alcohol use disorder (4.5%) were the most common and more often reported in stage 1b participants relative to other groups. Furthermore, alcohol, cannabis and tobacco use remained relatively consistent at 6- and 12-month follow-ups when compared to baseline use. Conclusion Alcohol was the most commonly used substance followed by cannabis and tobacco. Although substance use did not differ between those at different stages of risk, overall prevention strategies are still warranted for youth at-risk for SMI, especially those who are more symptomatic and potentially at greater risk of developing an SMI.