We often underestimate the ways our environment shapes our moods and general well-beings. We may feel happier when there’s sunshine or sleepier when it rains. We might even have our favorite seasons when we can embrace our preferred weather, beverages, and fashions. (I’m personally partial to the fall. Long live hot apple cider!) But for an estimated 5% of adults in the United States, season changes have higher stakes. According to the National Institute of Mental Health, seasonal affective disorder (SAD) is a type of depression that lasts 4-5 months out of the year in tandem with a given season. SAD is not fully considered its own separate disorder, but rather as a season-sensitive manifestation of major depression. This means that SAD symptoms, like major depression, include fatigue, loss of interest in otherwise enjoyed activities, having difficulty concentrating, and trouble with sleep.
Further SAD symptoms depend on when the depressive shift occurs. There are two main types of seasonal affective disorder: winter-pattern and summer-pattern. Interestingly, the additional SAD symptoms for each type seem to mirror each other. For example, winter-pattern SAD symptoms include hypersomnia (oversleeping), overeating, weight gain, and fatigue. On the other hand, summer-pattern symptoms include insomnia, lack of appetite, weight loss, and high anxiety. Between the two, the winter-pattern is much more common, with summer-pattern being very rare.
Though there is still a lot of research to be done on the demographics most impacted by SAD, most notably, women are 4X more likely than men to experience symptoms of the condition. Experts still aren’t sure why this is the case, but they often argue that the higher rate of SAD diagnosis in women is connected to women also being 2X more likely than men to experience depression. Research has yet to indicate the cause behind this as well, but many scientists conjecture that it may be linked to the more drastic fluctuations in hormones like estrogen. Seasonal affective disorder appears to be associated with imbalances in serotonin, melatonin, and vitamin D levels. For winter-pattern SAD, depressive symptoms may be a result of drops in serotonin and vitamin D levels and/or rises in melatonin levels. Serotonin, which is a hormone associated with happiness and sunshine, is transmitted less frequently with lower exposure to daylight. Vitamin D, which often reinforces serotonin activity, is a prohormone produced by our skin upon sunlight exposure. Melatonin is a hormone released in response to darkness and tends to make our bodies sleepy. In essence, the less daylight we receive, the more susceptible we become to serotonin and vitamin D deficiencies and melatonin surplus, which can ultimately lead to depressive symptoms. Furthermore, for women, changes in estrogen levels may also decrease serotonin release, making us more likely to experience the impact of this drop as depressive symptoms.
- Those who are diagnosed with SAD often begin to experience the symptoms as young adults, the onset potentially linked to the end of puberty.
- SAD, especially winter-pattern SAD, is much more prevalent among people who live far away from the equator and experience less daylight hours.
- SAD may have a genetic component since it appears to run in families.
- Most people with SAD also have other mental conditions like attention-deficit/hyperactivity disorder, bipolar depression, panic disorder, etc.
If you believe that you may be experiencing seasonal affective disorder, please reach out to a qualified medical professional for an optimized treatment plan. The experience of SAD symptoms have been exacerbated by the pandemic given that people are spending even less time out in daylight and these unprecedented times continue to be unmooring. Many experts may implement the individual or combined use of light therapy, psychotherapy, vitamin D supplements, and/or antidepressant medications. Here are some further resources: