The Holidays and the Heart of Darkness
For some, the autumnal equinox is a time of celebration. The increasingly shorter days usher in holidays in October, November and December in a blur of festive celebration with family and friends. For others however, the September solstice represents the start of a dark season, both literally and figuratively for people suffering from seasonal affective disorder (SAD). While others revel in holiday spirit, those afflicted with SAD experience profound mental and emotional changes as a result of the changing amount of daylight.
Symptoms of SAD can include increased hunger, especially for carbohydrates; increased desire to sleep, and weight gain, along with the traditional symptoms of depression (mood swings, irritability, memory problems, loss of interest in day to day activities, to name a few). The condition strikes only 5% of the US population, but disproportionately impacts the one million people who live in areas of high cloud cover in northern latitudes, including most of Western New York.
The culprit may be the dorsal raphe nucleus, an area deep within the brain that has close ties to the body’s ‘master clock’ of circadian rhythms. An area highly susceptible to melatonin, the region also controls levels of serotonin in the brain. Low levels of serotonin are linked to depression, while high levels create feelings of well-being. Researchers at Vanderbilt University recently conducted a study of mice exposed to a summerlike 16 hours of light and 8 hours of darkness and others exposed to a dismal 8 hours of light and 16 hours of darkness (comparable to Rochester, New York in December.) The serotonin neurons of the dark mice fired far more slowly than their sunny counterparts, and as a result, the mice showed key signs of depression. (A swim test is used to evaluate depression in rodents, as the availability of mice with Ph.D.s and research training is severely limited.)
In light of a national election that has left many feeling stunned and anxious, this SAD season may be harder than most. However, there are treatments to help SAD sufferers rebound more quickly or fight the malaise of depression. Light therapy, antidepressants, and cognitive behavioral therapy (a form of psychotherapy facilitated by a medical professional) can all reduce symptoms of the condition and result in a better quality of life for patients. If you or someone you know seems to be struggling this year, talk to your doctor or nurse about possible treatments. In the dark of winter, it’s hard to imagine the light of spring.
Green N, Jackson C, Iwamoto H, Tackenberg M, McMahon D. Photoperiod Programs Dorsal Raphe Serotonergic Neurons and Affective Behaviors. Current Biology. 2015;25:1389-1394.
Kurlansik S, Ibay A. Seasonal Affective Disorder. American Family Physician. 2012;86:1037-1041.
Ltd CRP. Cloudiest cities in US. Current Results. 2004. https://www.currentresults.com/Weather-Extremes/US/cloudiest-cities.php.
National Oceanic and Atmospheric Association. Ranking of cities based on % annual possible sunshine. Comparative Climatic Data. https://www1.ncdc.noaa.gov/pub/data/ccd-data/pctposrank.txt.