The Relationship between Vaping Cannabis and Frequency of Cannabis Use and Cannabis-Related Problems among Urban High School Students.

Vaping, including vaping cannabis, is increasing among adolescents. In this longitudinal study, we examined the relationship between vaping cannabis and frequency of cannabis use and related problems over 6 months among adolescents. Data were from 233 participants (46.8% male, 93.1% African American, mean age = 16.4 years) reporting cannabis use. The Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) assessed frequency of past 30-day cannabis use and cannabis-related problems at baseline, 3- and 6-months post-baseline. We used latent growth curve modeling to compare vaping to non-vaping adolescents on trends in cannabis use frequency and ASSIST cannabis scores. Adolescents who vaped cannabis (11.7%) had higher past 30-day frequency (mean = 17.89 days, SD = 10.49) of cannabis use at baseline compared to adolescents who had not vaped (mean = 12.1 days, SD = 10.93), but reported a significantly sharper decline in frequency of cannabis use (b = -0.34,  = 0.017). A significantly steeper decrease existed in the mean cannabis ASSIST scores for the vaping group than for the non-vaping group (b = -0.34,  = 0.014). Mean ASSIST scores on the cannabis subscale between the two groups were significantly different at 6-month follow-up (Vape mean = 6.00, SD = 8.12 vs. Non-vape mean = 9.6, SD = 9.39;  < 0.021). In a sample of cannabis-using adolescents, adolescents with experience vaping cannabis, compared to adolescents without vaping experience, on average reported sharper decreases in frequency of cannabis use and cannabis-related problems such as health or social problems.