6.6 % of national episodes delivered to adolescents, and 19.8 % to emerging adults.

Cannabis was the most common PDOC in youth treatment episodes.

Alcohol-focused episodes declined for young people from 2010 onward.

Planned treatment completion: 64 % for adolescents, 59 % for emerging adults.

Most treatment episodes were provided in non-residential settings.

Substance use disorders frequently begin in adolescence and emerging adulthood. Knowledge of trends in alcohol and other drug (AOD) service utilisation during these periods can inform policy development to align service delivery with treatment need.

Characterise trends in AOD treatment episodes among adolescents (aged 10–17) and emerging adults (aged 18–24) across Australia, and compare to adult trends (aged ≥25).

National data from the Alcohol and Other Drug Treatment Services – National Minimum Data Set were analysed (N = 2904,012). Joinpoint regression analysis was used to characterise trends in principal drug of concern, treatment setting, planned completion, and sex.

Cannabis was the most common principal substance of concern for adolescents and emerging adults. The proportions of episodes relating to cannabis, alcohol, and psychostimulants for emerging adults was stable from 2015 onward, while alcohol-related episodes declined for adolescents. Most episodes were provided in non-residential services, and treatment provision in home/outreach settings increased over time. 59.0 % of episodes for emerging adults and 64.4 % of episodes provided to adolescents (excluding assessment and information/education only) were completed. From 2014–2016 onward, an increase in the proportion of episodes provided to females among all three age groups was observed.

Observed trends in principal substance of concern were largely consistent with national and international drug market trends. The findings can inform service and policy development, with targeted attention toward the treatment of cannabis and psychostimulant use for younger populations indicated. Relatively stable treatment completion rates highlight the need for ongoing efforts to retain young people.

Substance use disorders

Emerging adult

Substance use treatment

Trends

© 2025 The Author(s). Published by Elsevier B.V.