Trajectories of adolescent alcohol and cannabis use into young adulthood

Abstract

Background Both alcohol and cannabis use carry health risks. Both are commonly initiated in adolescence. To date little research has described trajectories of adolescent cannabis or alcohol use or compared their respective consequences in young adulthood. Methods The design was a 10-year eight-wave cohort study of a state-wide community sample of 1943 Victorians initially aged 14-15 years. Moderate-and high-risk alcohol use was defined according to total weekly alcohol consumption. Moderate-and high-risk cannabis use were defined as weekly and daily use, respectively. Results Around 90% of young adults used either alcohol or cannabis. Although an association existed between alcohol and cannabis use, there was a tendency for heavy users to use one substance predominantly at any one time. Weekly or more frequent cannabis use in the absence of moderate-risk alcohol use in teenagers predicted a sevenfold higher rate of daily cannabis use in young adults but only a twofold increase in high-risk alcohol use. Conversely, moderate-risk adolescent alcohol use in the absence of weekly cannabis predicted an approximately threefold increased rate of both high-risk drinking and daily cannabis use in young adulthood. Selective heavy cannabis use in both adolescence and young adulthood was associated with greater illicit substance use and poorer social outcomes in young adulthood than selective alcohol use. Conclusions Heavier teenage cannabis users tend to continue selectively with cannabis use. Considering their poor young adult outcomes, regular adolescent cannabis users appear to be on a problematic trajectory.

Tobacco, alcohol, cannabis and other illegal drug use among young adults: The socioeconomic context

“…With notable exceptions (Merline et al, 2004;Patton et al, 2007), past studies which report on the relationship between socioeconomic position and substance use studied one substance at a time (Fagan et al, 2005;Perkonigg et al, 2008;Schulenberg et al, 1996;Schulenberg et al, 2005;Swift et al, 2008) or overall symptoms of abuse (Barrett and Turner, 2006), making it difficult to make cross-substance comparisons.…”

“…More broadly, although recent changes in substance use in adolescence are documented, few studies have monitored trends in young adults (Merline et al, 2004;Patton et al, 2007;Perkonigg et al, 2008) and there is need to update knowledge on this risk prone segment of the population. With notable exceptions (Merline et al, 2004;Patton et al, 2007), past studies which report on the relationship between socioeconomic position and substance use studied one substance at a time (Fagan et al, 2005;Perkonigg et al, 2008;Schulenberg et al, 1996;Schulenberg et al, 2005;Swift et al, 2008) or overall symptoms of abuse (Barrett and Turner, 2006), making it difficult to make cross-substance comparisons.…”

Cannabis Use and Disorder Transitions Among a Mixed Community Sample of At-Risk Adolescents and Adults: A Prospective New Zealand Study

“…However, incidence, escalation, and persisting cannabis use and CUD was a nascent trend in more recent prospective studies of cohorts aged in their mid-late 20s [10,14,[17][18][19][20][21][22] and 30s [13,16]. Cannabis use appears less transient than previously thought.…”

“…For example, prototypical subgroups include: high chronic, decreasers, increasers, experimental users, abstainers, 'fling', rare. Conjoint/comorbid cannabis, alcohol, and tobacco use trajectories are also appearing [14,[24][25][26].…”

“…Cannabis dependence develops twice as rapidly in adolescents than adults at any consumption level [6][7][8][9]; approximately 14-16% adolescentonset and 8% adult-onset users become dependent [3]. While early cannabis initiation and entrenched use confer the highest risk of dependence and other adverse outcomes [7][8][9][10][11], even occasional (weekly) use continued into young adulthood predicts later drug and other problems [12][13][14]. Recognizing early manifestations of cannabis use disorder (CUD) is crucial for identifying those for whom timely intervention might avert further harm.…”