A study published in March 2023 suggests melatonin could decrease self-harm in youths, but the results should be interpreted with caution.
Sleeping disorders are common among young people, particularly those suffering from psychiatric disorders, which can affect their health, development, regulation of emotions, while also increasing their risk for accidental injuries, self-harm, and suicide1.
Observations from the study
The study titled “Melatonin use and the risk of self-harm and unintentional injuries in youths with and without psychiatric disorders” studied a population group of over 25,500 children and teenagers in Sweden who were prescribed melatonin, a hormone produced by the brain to regulate sleep and the circadian rhythm (our 24-hour internal clock regulated by light exposure). Melatonin is the most commonly prescribed drug in Sweden to young people with sleeping disorders. Most of the children and teenagers in the study had a psychiatric disorder, mainly ADHD, autism, depression, or anxiety. “Poisoning” was the most common method of self-harm used, followed by cutting and piercing. Researchers compared the risks of self-harm in the sample between the month before the initiation of melatonin treatment and the twelve months after the start of the treatment. A decrease in self-harm was observed immediately after the initiation of melatonin treatment, particularly among females, but the risk remained high. The risk for unintentional injury however did not change with treatment1.
Limitations
While the study benefited from a large sample, it has several limits. While there was an initial decrease in self-harm in the month following melatonin treatment, it is unclear it was representative as little difference in self-harm risk was observed between the overall on and off-melatonin periods. Furthermore, the month preceding treatment might not be representative of the self-harm habits of young people as a change in behavior might have led to medical care, for instance because of an increase in frequency or severity of self-harm or a general worsening of the child’s mental health. This theory seems supported by the fact that the study found an increase of self-harm in the last two to three months prior to the start of the treatment, with a peak in the month before. Similarly, the following months might not only be positively impacted by the melatonin treatment, but also by a growing focus on youths’ mental health, as suggested by the researchers who led the study. While the study excluded individuals who also took antidepressants, little could be known of children and teenagers who started therapy or other types of treatment for instance.
While interpreting these results with caution, it seems safe to assume that providing medical attention to young people can lead to a decrease of self-harm and that sleeping disorders are associated with psychiatric disorders. A study published in October 20232 found that a balanced exposure to light during the day and darkness during the night was associated with a reduction of psychiatric disorders and self-harm, suggesting that the circadian rhythm is linked with mental health. It is unclear however if imbalanced circadian rhythm is a cause or a consequence of poor mental health. Further research is therefore needed to get a better understanding of the connection between self-harm, sleep and melatonin.
References
[1] Leone, M., Kuja-Halkola, R., Lagerberg, T., Bjureberg, J., Butwicka, A., Chang, Z., Larsson, H., D’Onofrio, B. M., Leval, A., & Bergen, S. E. (2023). Melatonin use and the risk of self-harm and unintentional injuries in youths with and without psychiatric disorders. The Journal of Child Psychology and Psychiatry, 64(7), 1027-1036. https://doi.org/10.1111/jcpp.13785
[2] Burns, A. C., Windred, D. P., Rutter, M. K., Olivier, P., Vetter, C., Saxena, R., Lane, J. M., Phillips, A. J. K., & Cain, S. W. (2023). Day and night light exposure are associated with psychiatric disorders: an objective light study in >85,000 people. Nature Mental Health. https://doi.org/10.1038/s44220-023-00135-8
Exploring self-harm 