Summary: Melatonin reduces self-harm in young people with depression and anxiety. The effects were more pronounced in females with anxiety and depression.
Source: Karolinska Institute
Medical sleep treatment may reduce self-harm in young people with anxiety and depression, an observational study from Karolinska Institutet in Sweden suggests. The risk of self-harm increased in the months preceding melatonin prescription and decreased thereafter, especially in girls.
The study is published in The Journal of Child Psychology and Psychiatry.
Melatonin is a hormone that controls the sleep-wake cycle and is the most commonly prescribed drug for sleep disturbances in children and adolescents in Sweden. Melatonin use has dramatically increased in recent years, and it is available over the counter in Sweden since 2020.
“Given the established link between sleep problems, depression, and self-harm, we wanted to explore whether medical sleep treatment is associated with a lower rate of intentional self-harm in young people,” says Dr Sarah Bergen, docent at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, who led the study.
Psychiatric disorders were common
The study identified over 25,500 children and teenagers between the ages of 6 and 18 who were prescribed melatonin in Sweden. Over 87 percent had at least one psychiatric disorder, mainly attention-deficit hyperactivity disorder (ADHD), anxiety disorders, depression, or autism spectrum disorder. Self-harm was about five times more common in girls than in boys.
The researchers estimated the risks of self-harm in the same individual while on or off medication by comparing the risk in the last unmedicated month with the twelve months after melatonin treatment was initiated. By doing so, they were able to take into account background factors that may affect associations, such as genetics, sleep disorder severity, or psychiatric disorders.
The risk of self-harm increased shortly before melatonin was prescribed and decreased by about half in the months following the initiation of treatment. Image is in the public domain
The risk of self-harm increased shortly before melatonin was prescribed and decreased by about half in the months following the initiation of treatment. Risk reduction was particularly evident among adolescent girls with depression and/or anxiety disorders.
Youth mental health crisis
“There is currently a youth mental health crisis, and the risk of self-harm and suicide is high,” says Sarah Bergen. “Our findings support the hypothesis that sleep interventions may reduce self-harm in this population, especially in girls.”
As it was an observational study, it cannot establish a causal relationship between melatonin and reduced self-harm rates. To check whether the use of other medications might have affected the findings, analyses were also carried out which excluded antidepressant users. The results were similar.
“This suggests that melatonin might be responsible for the reduced self-harm rates, but we cannot rule out that the use of other psychiatric medications or psychotherapy may have influenced the findings,” says Dr Marica Leone, first author of the study and former PhD student in Sarah Bergen’s research group.
Funding: The research was mainly financed by the European Union’s Horizon 2020 research and innovation programme. Co-authors Marica Leone and Amy Leval are employees of Johnson & Johnson. Co-author Henrik Larsson has received grants from Shire Pharmaceuticals, personal and speaker fees from Medice, Shire/Takeda Pharmaceuticals and Evolan Pharma AB, and sponsorship for a conference on ADHD from Shire/Takeda Pharmaceuticals and Evolan Pharma AB, all outside the submitted work.
Melatonin use and the risk of self-harm and unintentional injuries in youths with and without psychiatric disorders
Sleep disorders in youth have been associated with increased risks of injury, including suicidal behavior. This study investigated whether melatonin, which is the most common medication for sleep disturbances in youth in Sweden, is associated with a decreased risk of injury.
This population-based cohort study included 25,575 youths who initiated melatonin treatment between ages 6 and 18. Poisson regression was used to estimate rate of injuries in the year prior to and following melatonin treatment initiation. A within-individual design was used to estimate relative risks by comparing injury risk in the last unmedicated month with injury risks in the 12 months after medication initiation. Analyses were stratified by sex, injury type, psychiatric comorbidities and age at melatonin-treatment initiation.
While body injuries, falls and transport accident rates were comparable in the year before and after melatonin-treatment initiation, the risk of self-harm was highest in the months immediately prior to medication, and decreased thereafter. This was particularly prominent among adolescents with depression and/or anxiety, with females displaying greater absolute risks than males. Compared to the last unmedicated month, the 12 months post medication initiation had decreased relative risks for self-harm, with an IRR [95% CI] in the month following melatonin-treatment initiation of 0.46 [0.27–0.76] among adolescent females with psychiatric disorders, after excluding antidepressant users.
Decreased risk of intentional self-harm was observed following melatonin-treatment initiation among females with depression and anxiety, suggesting that sleep interventions could be considered in an effort to reduce risk of self-harm in this population.