Adolescent polysubstance use, particularly among youth with early-onset cannabis use (CU), is a growing concern. This article delves into a study that examines the various polysubstance use profiles among adolescents with early-onset CU and how these profiles impact CU outcomes in early adulthood.

Study Overview

The study aimed to determine whether outcomes in early adulthood are best explained by early-onset CU itself or by resulting polysubstance use profiles. Conducted as part of the Québec Longitudinal Study of Child Development, the research analysed data from 794 participants who reported lifetime CU by age 21.

Participants

Participants were stratified into three groups based on the age of CU onset:

• Early-Onset CU: 349 participants who began using cannabis at age 15 or younger.
• Later Adolescent-Onset CU: 359 participants who began using cannabis between ages 16 and 18.
• Adult-Onset CU: 86 participants who began using cannabis at age 19 or older.

Methodology

Self-reported substance use data were collected from the early-onset CU group at ages 15 and 17, while CU frequency and problem CU were assessed at age 21 for all participants. Repeated measures latent profile analyses were used to identify distinct polysubstance use profiles within the early-onset CU group.

Key Findings

Polysubstance Use Profiles

Four distinct polysubstance use profiles were identified among youth with early-onset CU:

1. Light Users: 54% of the early-onset group.
2. Escalating Users: 13% of the early-onset group.
3. Frequent Users (Without Cigarettes): 14% of the early-onset group.
4. Frequent Users (With Cigarettes): 19% of the early-onset group.

CU Outcomes at Age 21

The study found significant differences in CU outcomes at age 21 based on these profiles:

• Escalating and Frequent (With Cigarettes) Users: These individuals showed consistently greater CU frequency and problem CU compared to those in the later adolescent-onset or adult-onset CU groups.
  • Effect Sizes: β range = 0.13 to 0.40; Cohen’s f² range = 0.02 to 0.12.

Implications

The findings suggest that early-onset CU is not a homogenous behaviour but rather follows distinct polysubstance use trajectories. These trajectories are differentially associated with the risk for future problem CU, highlighting the need for targeted interventions based on specific usage profiles.

Conclusion

The study provides crucial insights into the diverse polysubstance use patterns among adolescents with early-onset CU and underscores the importance of considering these profiles when addressing CU outcomes in early adulthood.

Source: Springer