By Katherine Schwartz '19

While darker days and dropping temperatures may make anyone feel down, research suggests that there is a scientific explanation behind winter lethargy. Seasonal Affective Disorder, or SAD, is a type of depression related to the changing of the seasons. Most prevalent among young adults, there are over three million cases of SAD in the US. SAD entails symptoms of depression or temporary depressive episodes, typically beginning in the fall and continuing into the winter, then waning in the spring and summer. Numerous factors may contribute to or cause SAD, however, treatments are fairly simple and usually successful.

Probable factors that trigger SAD include: a reduced level of sunlight in the fall and winter, disrupting one’s circadian rhythm and engendering depressive symptoms; lower sunlight causing a drop in serotonin levels, the neurotransmitter that regulates mood; and the shifted climate of the seasons altering melatonin levels, leading to irregular sleep patterns. In addition to such environmental factors, there may be biological conditions causing SAD. One study from the National Institute of Mental Health found that those with SAD have 5% more serotonin transporter protein during the winter than summer. With more serotonin protein present, less serotonin is available at the synapse, the junction enabling cell to cell communication, as the protein recycles neurotransmitters back into the presynaptic neuron. These findings suggest that those who struggle to regulate serotonin are the most probable candidates for SAD. Another condition common in people with SAD is proneness to overproduction of melatonin, causing excessive sleepiness. Finally, individuals with SAD may be deficient in Vitamin D, naturally producing less of it. In addition, SAD is particularly prevalent among women. In fact, according to the National Institute of Medical Health, women are diagnosed four times more often than men. Geography also plays a major role in one’s susceptibility to SAD. According to the Mayo Clinic, SAD most frequently affects individuals who live far north or south of the equator, resulting in less sun exposure during the winter. For example, 1% of individuals living in Florida have been diagnosed with SAD, while 9% in New England are reportedly affected.

With these numerous causes, it is important to identify the symptoms of SAD in order to address it. While symptoms of major depression include feelings of sluggishness, lack of interest, insomnia, and changes in appetite, symptoms specific to the winter pattern of SAD are: lack of energy, hypersomnia (excessive sleepiness), weight gain, and social withdrawal. To be officially diagnosed with SAD, one must express the symptoms of major depression during the affected seasons for more than two years. Once diagnosed, treatment can begin. While treatments range from medication to simple lifestyle changes, the three main types of treatment include: light therapy (phototherapy), medication, and psychotherapy. Light therapy, or phototherapy, involves exposure to artificial light that mimics the sun. Those with SAD may sit in front of a light box for 20-60 minutes everyday. Medication treatments include Selective Serotonin Reuptake Inhibitors (SSRIs), or other antidepressants. Finally, psychotherapy, or cognitive behavioral therapy, entails methods to identify and address negative thoughts as well as ways to engage in enjoyable activities. Meanwhile, simpler lifestyle solutions include spending more time outside, exercising regularly, and making one’s environment sunnier. This can be as easy as opening blinds.

By understanding the causes, symptoms, and treatments of SAD, one can take preventive measures against the disease. Though occasional melancholia in the winter is normal, if depressive symptoms persist, one should consider treating for SAD. Such diseases need not be feared, as SAD is an impermanent, common, and treatable illness.

“Seasonal Affective Disorder (SAD).” Mayo Clinic, Mayo Foundation for Medical Education and Research, 25 Oct. 2017, www.mayoclinic.org/diseases-conditions/seasonal-affective-disorder/symptoms-causes/syc-20364651.

The National Institute of Medical Health. “Seasonal Affective Disorder.” National Institute of Mental Health, U.S. Department of Health and Human Services, 2016, www.nimh.nih.gov/health/topics/seasonal-affective-disorder/index.shtml.

"presynaptic neuron." Farlex Partner Medical Dictionary. 2012. Farlex 3 Mar. 2018 https://medical-dictionary.thefreedictionary.com/presynaptic+neuron

“Synapse.” Biology Online, www.biology-online.org/dictionary/Synapse.