Stability and Change in Substance Use Among Swedish Adolescents: A Latent Transition Analysis.

Background: Research is needed on how substance use patterns develop over time in the general adolescent population. This knowledge is crucial in calibrating prevention and other interventions. Method: The study concerns use of cigarettes, alcohol, and cannabis in a nationally representative cohort of Swedish adolescents (n = 3999). Two waves (9th and 11th school grade) from the Futura01 study were analyzed using latent transition analysis (LTA) and multinomial regression analysis. Results: Four substance use patterns, were identified, ranging from Non-user, Alcohol experienced, Alcohol User to Co-user of cigarettes, alcohol, and cannabis. Statuses thus conveyed a continuum from no use to more advanced use. Half of the individuals remained in their original status between time-points, and half transitioned, most often one step on the continuum. Alcohol user was the most stable status over time (0.78), and the Non-user status the least (0.36). The probability of remaining in the Alcohol experienced status was 0.57, and 0.45 for the Co-user status. There was a low probability of transitioning from alcohol to cannabis use. Females were more likely to belong to Alcohol experienced and males to Co-user statuses, but these associations weakened over time. Conclusions: The study identified transitions across substance use statuses between time-points. These usually concerned different levels of alcohol use, and not into more advanced substance use that included the illegal substance cannabis. The study corroborates that young Swedes belong to a "sober" generation and usually do not transition from legal into illegal substance use during late adolescence, though with some gender differences.