Melatonin and SAD- A Potential Link

Melatonin and SAD- A Potential Link

Seasonal affective disorder (SAD) is a recurring major depressive disorder with a seasonal pattern. According to the DSM-V diagnostic criteria, the patient must have a depression that starts and ends during a specific season, annually for at least two years, and have more episodes of depressive episodes that season without depressive episodes over a lifetime (Meesters & Gordijn, 2016). SAD occurs more commonly in winter but may also be present in summer. Individuals with SAD have problems with regulating serotonin, which regulates mood (Meesters & Gordijn, 2016). SERT is a protein that transports serotonin across the neurons. Patients with SAD have low SERT levels during winter due to the diminishing sunlight, which decreases serotonin levels, thus causing depression (Meesters & Gordijn, 2016).

Individuals with SAD also have problems with the overproduction of melatonin. Melatonin is produced by the pineal gland and is responsible for regulating sleep. During winter, it becomes darker, and melatonin production increases, resulting in lethargy and sleepiness (Zghoul, 2020). A combination of increased melatonin and decreased serotonin affect circadian rhythms. For individuals with SAD, the circadian rhythm is timed differently, making it hard for individuals to adjust during seasonal changes.

One of the non-drug therapies for SAD is light therapy. This approach aims to understand the difference that decreased daylight can trigger SAD. Light therapy seeks to replace the diminished sunlight by utilizing bright artificial light more so in the morning (Glod, 2017). The light boxes emit full spectrum light similar to daylight. It relieves SAD symptoms when an individual sits in front of a lightbox from fall to spring in the morning (Glod, 2017). The side effects of light therapy are more severe than those of pharmacological agents. This therapy should be monitored by a healthcare professional.

References

Glod, C. (2017). Seasonal affective disorder (SAD) and light therapy: State of the science. https://doi.org/10.26226/morressier.5885d713d462b8028d891116

Meesters, Y., & Gordijn, M. C. (2016). Seasonal affective disorder, winter type: Current insights and treatment options. Psychology Research and Behavior Management, 9, 317-327. https://doi.org/10.2147/prbm.s114906

Zghoul, T. (2020). Can we prevent seasonal affective disorder (SAD) with melatonergic agents? BJPsych Advances, 26(4), 193-197. https://doi.org/10.1192/