Summary: Melatonin treatment for sleep problems was associated with lower rates of self-harm among young people diagnosed with depression and anxiety, with the strongest reductions observed in adolescent girls.
Source: Karolinska Institute
A large observational study from Karolinska Institutet in Sweden suggests that medical treatment for sleep problems using melatonin may be linked to a reduced risk of intentional self-harm among children and adolescents with anxiety and depression. The researchers observed an increase in self-harm risk in the months before melatonin was prescribed and a marked decline in the months that followed, especially among girls.
The findings are reported in The Journal of Child Psychology and Psychiatry.
Melatonin, a naturally occurring hormone that regulates the sleep–wake cycle, is the most frequently prescribed medication for sleep disturbances in children and adolescents in Sweden. Its use has risen substantially in recent years and, since 2020, melatonin has also been available over the counter in Sweden.
“Because sleep problems are closely linked with depression and self-harm, we examined whether initiating medical sleep treatment corresponds with changes in the rate of intentional self-harm among young people,” says Dr Sarah Bergen, docent at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet, who led the study.
Study population and psychiatric comorbidity
Using Swedish national registers, the team identified 25,575 children and adolescents aged 6–18 who began melatonin treatment. More than 87% of these young people had at least one recorded psychiatric diagnosis, most commonly attention-deficit hyperactivity disorder (ADHD), anxiety disorders, depression, or autism spectrum disorder. The analysis also found that self-harm incidents were about five times more common in girls than in boys within this cohort.
To reduce confounding by individual background factors—such as genetic predisposition, severity of sleep problems, or coexisting psychiatric conditions—the researchers used a within-individual design. They compared each participant’s risk of self-harm in the final unmedicated month before starting melatonin with risks across the 12 months after treatment began. This approach compares rates within the same person rather than between different people, helping to account for stable personal characteristics.
Overall, rates of accidental injuries (including body injuries, falls and transport accidents) were similar before and after melatonin initiation. However, intentional self-harm showed a distinct pattern: risk peaked in the months immediately preceding the first melatonin prescription and declined in the months following treatment initiation. The decline in self-harm after starting melatonin was particularly evident among adolescents diagnosed with depression and/or anxiety, and the absolute risk remained higher for females than males.
Implications amid a youth mental health crisis
“We are facing a significant youth mental health crisis, with high levels of self-harm and suicide risk,” notes Dr Bergen. “These findings support the idea that addressing sleep problems could be a useful component of efforts to reduce self-harm among young people, particularly adolescent girls with depression or anxiety.”
Because this study is observational, it cannot prove that melatonin caused the reduction in self-harm rates. To test whether concurrent antidepressant use explained the results, the researchers repeated analyses excluding individuals who used antidepressants; the pattern of reduced self-harm following melatonin initiation remained similar. For adolescent females with psychiatric disorders and no antidepressant use, the incidence rate ratio (IRR) for self-harm in the month after starting melatonin was 0.46 (95% CI: 0.27–0.76) compared with the final unmedicated month.
“These results indicate that melatonin treatment may play a role in lowering self-harm risk, though we cannot rule out contributions from other psychiatric medications, psychotherapy, or changes in clinical monitoring that often accompany the start of any new treatment,” says Dr Marica Leone, the study’s first author and a former PhD student in Bergen’s group.
Funding and disclosures
The research was primarily funded by the European Union’s Horizon 2020 research and innovation programme. Two co-authors, Marica Leone and Amy Leval, are employed by Johnson & Johnson. Another co-author, Henrik Larsson, has received research grants and honoraria from various pharmaceutical companies unrelated to the submitted work. These relationships are disclosed by the authors.
About this psychopharmacology research news
Author: Press Office
Source: Karolinska Institute
Contact: Press Office – Karolinska Institute
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Original Research: Open access. “Melatonin use and the risk of self-harm and unintentional injuries in youths with and without psychiatric disorders” by Sarah Bergen et al., Journal of Child Psychology and Psychiatry
Abstract
Melatonin use and the risk of self-harm and unintentional injuries in youths with and without psychiatric disorders
Background
Sleep disturbances in children and adolescents are associated with higher risks of injury, including behaviors linked to self-harm and suicide. This study assessed whether initiation of melatonin, the most commonly prescribed sleep medication for youth in Sweden, was associated with changes in injury risk.
Methods
In this population-based cohort, 25,575 youths aged 6–18 who started melatonin were followed. Poisson regression estimated injury rates during the year before and the year after treatment initiation. A within-individual design compared each person’s risk in the last unmedicated month with risks during the 12 months after starting melatonin. Analyses were stratified by sex, injury type, psychiatric comorbidity, and age at treatment start.
Results
Rates of accidental injuries (body injuries, falls, transport accidents) were similar before and after melatonin initiation. In contrast, self-harm risk was highest in the months immediately before medication began and declined afterward, especially among adolescents with depression and/or anxiety. Females showed higher absolute risks than males. After excluding antidepressant users, adolescent females with psychiatric disorders had a reduced IRR for self-harm in the month following melatonin initiation of 0.46 (95% CI: 0.27–0.76) compared with the last unmedicated month.
Conclusions
The study observed a decrease in intentional self-harm following initiation of melatonin, particularly among females with depression and anxiety, supporting the consideration of sleep-focused interventions as part of strategies to reduce self-harm risk in this vulnerable group.