Teens who used both tobacco and cannabis together had worse behavioral problems than those using either substance alone

Concurrent tobacco and cannabis users had significantly higher odds of externalizing problems compared to tobacco-only use (AOR 1.83) and cannabis-only use (AOR 1.85). High externalizing problems were most common in the concurrent group (61.6%), followed by cannabis-only (48.5%), tobacco-only (46.3%), and nonusers (30.4%). Internalizing problems did not significantly differ between substance use groups.

Cross-sectional analysis of PATH Study wave 6 data (nationally representative, March-November 2021). 5,585 youths aged 14-17. Past 30-day tobacco and cannabis use categorized into four exclusive groups. Mental health measured with the modified GAIN-Short Screener.

Tobacco and cannabis co-use is common among teens but rarely studied as a distinct pattern. Finding that the combination amplifies externalizing problems more than either substance alone suggests these users may need integrated interventions targeting both substances simultaneously.

The specificity to externalizing problems (aggression, rule-breaking, impulsivity) rather than internalizing problems (depression, anxiety) raises questions about whether the combined neurochemical effects of nicotine and THC particularly affect impulse control and behavioral regulation in developing brains.

Cross-sectional design cannot determine whether co-use causes worse mental health or whether teens with existing behavioral problems are more likely to use both substances. Self-reported substance use and mental health. Data from 2021 during COVID-19 pandemic.