Twenty-year outcomes in adolescents who self-harm show worrying levels of substance abuse by age 35

A study by researchers from the Murdoch Children's Research Institute (MCRI) that followed a sample of almost 2000 Victorian school children from the age of 14 until the age of 35 found that social disadvantage, anxiety, and licit and illicit substance use (in particular cannabis), were all more common in participants who had reported self-harm during adolescence.

The longitudinal study, the Victorian Adolescent Health Cohort Study, was the first in the world to document health-related outcomes in people in their 30s who had self-harmed during their adolescence. Until now, very little has been known about the longer-term health and social outcomes of adolescents who self-harm.

Published in the new Lancet Child and Adolescent Health journal, the study found the following common elements:

• People who self-harmed as teenagers were more than twice as likely to be weekly cannabis users at age 35
• Anxiety, drug use, and social disadvantage were more common at age 35 among participants who had self-harmed during their teenage years. While most of these associations can be explained by things like mental health problems during adolescence and substance use during adolescence, adolescent self-harm was strongly and independently associated with using cannabis on a weekly basis at age 35 years
• Self-harm during the adolescent years is a marker for distress and not just a 'passing phase'

The findings suggest that adolescents who self-harm are more likely to experience a wide range of psychosocial problems later in life, said the study's lead author, Dr Rohan Borschmann from MCRI.

"Adolescent self-harm should be viewed as a conspicuous marker of emotional and behavioural problems that are associated with poor life outcomes," Dr Borschmann said.

The study found that anxiety, drug use, and social disadvantage were more common at age 35 among participants who had self-harmed during their teenage years.

"While most of this can be explained partly by things like mental health during adolescence and substance use during adolescence, adolescent self-harm was strongly and independently associated with using cannabis on a weekly basis at age 35 years," Dr Borschmann said.

Interventions during adolescence which address multiple risk-taking behaviours are likely to be more successful in helping this vulnerable group adjust to adult life.