It’s currently autumn. The trees are gently changing colors, the temperature is moderately becoming cooler, and slowly the days are beginning to get shorter. Soon, time will be passing by swiftly, and winter will be upon us. As winter approaches, many animals will be going into hibernation. However, they may not be the only ones to be affected by the changes in seasons.
As the weather changes, many individuals will struggle with Seasonal Affective Disorder (SAD). The National Institute of Mental Health characterizes SAD as not a discrete disorder, but rather as a type of depression that recurs seasonally (NIH). Those diagnosed with Seasonal Affective Disorder display major depression during certain seasons (most commonly in the winter), for at least 2 years. Symptoms of SAD include low energy, social withdrawal, weight change, and changes to sleep schedule. SAD is less likely to occur during the summer season where it is more characterized by restlessness and weight loss. A more subsyndromal version is known as S-SAD, simply called winter blues (Melrose).
The exact causes of SAD are yet to be found. However, in an overview of the disorder completed at Athabasca University, possible symptoms are explained. During the winter, the amount of sunlight decreases as the days are shorter. This decline in sunlight exposure has a biochemical effect on a person’s mental state. The reduced sunlight exposure to the skin correlates to a decreased production of Vitamin D (Melrose). Vitamin D deficiency has often been linked to depressive symptoms. A study published in the Journal of Chemical Neuroanatomy also linked Vitamin D receptors to areas of the brain associated with depression (Eyles). Vitamin D plays a role in releasing serotonin, a neurotransmitter whose low levels are often correlated with depression. In addition, melatonin is a hormone that regulates sleep. The pineal gland releases melatonin as photoreceptors in the eyes sense a decrease in light. High levels of melatonin are correlated to the sense of sleepiness. Together, levels of serotonin and melatonin contributed to SAD.
There are several possible treatments for SAD including medication and psychotherapy. However, light therapy is cited as among the most popular due to having the least side effects. Dating back to the 1980s, physician Norman Rosenthal founded an effective clinical treatment for SAD. As a native South African, Rosenthal noticed a decrease in his productivity during the winter season, which would return by spring (Rosenthal). While working at the National Institute of Health (NIH), Rosenthal had worked with Al Lewy, a researcher of melatonin, a hormone that regulates wakefulness. Another researcher at the institution included Tim Wehr, who had done research on how light suppressed melatonin and impacted circadian rhythms. Together, the researchers concluded that bright light could effectively treat patients with SAD (Overy and Tansey, 2014). According to a study done by Terman and Terman, lights with an intensity of 10,000 lux that run for about 30 to 40 minutes have been shown to be most effective (Terman & Terman, 2005). It is important not to mistake SAD for just a down feeling. Certain cases can severely affect an individual to the point that they can not function. Furthermore, as a seasonal disorder, it is vital to pay attention to the symptoms that may change when winter is finally over.
C. Overy and E. Tansey, The Recent History of Seasonal Affective Disorder (SAD), vol. 51 of Wellcome Witnesses to Contemporary Medicine, University of London, London, UK, 2014, http://www.histmodbiomed.org/sites/default/files/W51 LoRes.pdf
Eyles, D. W., Smith, S., Kinobe, R., Hewison, M., & McGrath, J. J. (2005). Distribution of the vitamin D receptor and 1 alpha-hydroxylase in human brain. Journal Of Chemical Neuroanatomy, 29(1), 21-30.
Melrose, S. (2015). Seasonal Affective Disorder: An Overview of Assessment and Treatment Approaches. Depression Research & Treatment, 1-6. doi:10.1155/2015/178564
N. Rosenthal, “What is seasonal affective disorder? Answers from the doctor who first described the condition,” Dr. Rosenthal’s personal website, http://www.normanrosenthal.com/seasonal-affective-disorder/
Seasonal Affective Disorder. (n.d.). Retrieved October 2017, from https://www.nimh.nih.gov/health/topics/seasonal-affective-disorder/index.shtml
Terman, M., & Terman, J.S. (2005). Light therapy for seasonal and nonseasonal depression: Efficacy, protocol, safety, and side effects. CNS Spectrums, 10, 647–663. doi:10.1017/s1092852900019611