First Used Nicotine/Cannabis Product and Associated Outcomes in Late Adolescents.

Background: Nicotine and tobacco product (NTP) and cannabis use are common in adolescence/young adulthood and increase risk for negative psychosocial outcomes. This study investigated associations among adolescent/young adults' initial experiences with NTPs, lifetime frequency of substance use, substance-related problems, and mental health symptoms.

Method: Adolescents and young adults enrolled in a study on NTP and cannabis use were asked at what age they initiated the use of NTPs and were assigned to groups based on which product or substance(s) they reported using at the earliest age. Participants who reported use of NTPs (in isolation, without cannabis) first ( = 78, "NTP-only"), simultaneous use of NTPs and cannabis first (e.g., blunt or bowl;  = 25, "Simult-only"), use of both NTPs in isolation and simultaneous use at the same age ( = 48, "NTP + Simult"), and no NTP use ( = 53, "NTP-naïve") were compared on substance use, substance-related problems, and mental health symptoms.

Results: Groups differed on lifetime frequency of NTP, simultaneous, and cannabis use, with NTP users reporting more substance use episodes and substance-related problems than the NTP-naïve group. The lifetime frequency of cannabis use did not differ across NTP use groups. NTP use was associated with increased anxiety and depression, with no significant differences between groups.

Conclusions: Adolescents and young adults who use nicotine may be at increased risk for greater nicotine use and mental health consequences, but initiating NTP use simultaneously with cannabis may not increase the risk of negative outcomes above and beyond nicotine initiation. Prospective longitudinal research is needed to establish temporal associations between first-used NTP/cannabis products and relevant outcomes.