Among low-income Chilean adolescents, cannabis misuse was one of four factors predicting new onset self-harm over six months, alongside depressive symptoms, suicidal thoughts, and poor problem-solving skills.
Read this if you want to understand risk factors for self-harm in adolescents.
14% of adolescents developed new self-harm within 6 months; cannabis misuse was a predictor
What the researchers found
In a cohort of 2,042 adolescents from socioeconomically deprived areas of Santiago, Chile, the lifetime prevalence of self-harm was 23%. Among those with no self-harm at baseline, 14% developed new self-harm episodes within six months.
In multivariable analyses controlling for other risk factors, cannabis misuse was independently associated with the onset of self-harm, alongside depressive symptoms, suicidal thoughts, and poor problem-solving skills.
The prevalence and incidence of self-harm differed substantially by gender, reflecting patterns seen in Western countries where self-harm is more common among females during adolescence.
Why it matters
Most research on adolescent self-harm has been conducted in Western, high-income countries. This study provides evidence from a low-income Latin American context, confirming that cannabis misuse is a risk factor for self-harm even in a different cultural and socioeconomic setting.
The numbers in context
2,042 adolescents, median age 14. Lifetime self-harm prevalence: 23%. 6-month incidence of new self-harm: 14%. Risk factors: depressive symptoms, suicidal thoughts, poor problem-solving, cannabis misuse.
How the study worked
This was a prospective cohort study nested within a cluster randomized controlled trial. 2,042 adolescents (median age 14) from deprived areas of Santiago, Chile were followed for 6 months. Self-harm was assessed at baseline and follow-up. Risk factors examined included depressive symptoms, suicidal thoughts, problem-solving skills, substance use, and demographic variables.
What this study cannot tell us
The study cannot determine whether cannabis misuse causes self-harm or whether both are driven by shared underlying factors. Cannabis misuse was self-reported. The 6-month follow-up period may not capture the full trajectory of self-harm behavior. The sample is specific to low-income areas of Santiago and may not generalize broadly.
How to read the evidence
This is a prospective cohort study with appropriate statistical controls, providing moderate evidence for the association.
When this study was published
Published in 2014. Adolescent self-harm research has expanded globally since.
The bigger picture
Self-harm in adolescents is a global public health concern and a strong predictor of future suicide attempts. Identifying modifiable risk factors like cannabis misuse and problem-solving skills is important for developing prevention interventions that can be adapted across cultural contexts.
Questions still open
- Does treating cannabis misuse reduce self-harm risk? Are problem-solving skill interventions effective at preventing self-harm? Do these risk factors operate similarly across different cultural contexts?
Common questions
Does cannabis cause self-harm?
Why is this study important if similar findings exist in Western countries?
Read the original research
Factors associated with the development of self-harm amongst a socio-economically deprived cohort of adolescents in Santiago, Chile.
Social psychiatry and psychiatric epidemiology, 49(4), 629-37
Citation
Spears, Melissa; Montgomery, Alan A; Gunnell, David; Araya, Ricardo. (2014). Factors associated with the development of self-harm amongst a socio-economically deprived cohort of adolescents in Santiago, Chile.. Social psychiatry and psychiatric epidemiology, 49(4), 629-37. https://doi.org/10.1007/s00127-013-0767-y
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