Feeling a mood change when the seasons shift is a common experience for those who live in areas that have a low percentage of daytime hours. In conjunction with a lack of sunlight, the weather doesn’t always allow for outside activity. We surely appreciate our climate when we see images of those dealing with constantly overcast, dark, snowy days as they yearn for warmer, sunny ones like here in Tucson; seasonal changes can have a marked impact on our health.
S.A.D. (seasonal affective disorder), is a type of depression with symptoms that often appear during late fall or early winter when sunlight is less prevalent, and usually resolve during the sunnier days of spring and summer. For others, S.A.D. symptoms occur even in the spring and summer, although symptoms may be slightly different. Those that experience S.A.D. in the spring and summer may lose weight due to poor appetite, have insomnia, and feel anxious. In contrast, those who experience S.A.D. during the fall and winter, may experience weight gain, have poor concentration, feel especially lethargic and oversleep.

According to the National Institute of Health, 6% of the U.S. population, primarily in northern climates, is affected by S.A.D. in its most marked form. Another 14% of the adult U.S. population suffers from a lesser form of seasonal mood changes, known as winter blues. Of course, seasonality affects people all over the world. The prevalence of S.A.D. in Oslo, Norway, was reported as 14% in contrast to 4.7% in New York City. In fact, someone may have winter blues while living in southern climates and convert to full blown S.A.D. if they move to a northern climate.
S.A.D. is reported by approximately 10-20% of people with depression and 15-22% percent of those with bipolar disorder. If you have a family history of depression or S.A.D., you are also more likely to experience it. The exact reason why it occurs is unknown- several factors are believed to contribute:
- Circadian rhythym: Sunlight helps regulate your circadian rhythm, which then sets up your body’s routine of when to sleep and wake. Lack of sunlight due to seasonal changes can impact this routine- those that live further from the equator, where fall and winter days are shorter, may experience S.A.D. more frequently. Since this syndrome is linked to lack of light, people with S.A.D. may become depressed during cloudy weather at any time of the year, or if they are confined to windowless offices or basement apartments.
- Melatonin levels change: Melatonin is primarily a hormonal signal of darkness. To understand the role of melatonin in the winter form of S.A.D., it is important to note that melatonin is a factor in regulating both circadian and seasonal rhythyms. If your sleep routine is off, the brain may produce melatonin at inconsistent levels, impacting your sleep even more.
- Reduction in seratonin: A drop in seratonin, a brain chemical that impacts mood, might play a role in S.A.D. Reduced sunlight can cause a drop in seratonin that may trigger depression.
Symptoms may start out mild and become more severe as the season progresses. According to the Mayo Clinic, signs and symptoms of SAD may include:
• Feeling depressed most of the day, nearly every day
• Losing interest in activities you once enjoyed
• Having low energy
• Having problems with sleeping
• Experiencing changes in your appetite or weight
• Feeling sluggish or agitated
• Having difficulty concentrating
• Feeling hopeless, worthless or guilty
• Having frequent thoughts of death or suicide
If you have any of these symptoms, take them seriously and speak to your provider about treatment. As stated in a previous post, new studies show that seasonal mood changes might be linked to how the brain processes light, leading some to experience depressed symptoms with decreased exposure to sunlight, while others do just fine with the change. Light therapy (phototherapy) is a treatment method utilized by some providers, where a light box helps balance out the deficit of natural sunlight. But, be sure to speak to your provider, as increasing exposure too fast or for too long may induce manic symptoms if you have bipolar disorder. Also seek out advice if you have vision conditions like glaucoma, to ensure that the light box doesn’t cause unintended complications. Other forms of treatment include medication and psychotherapy. Often, treatment programs combine elements of multiple treatment options.
It took months for anyone to diagnose a family member who went to college in Massachusetts. The dramatic change from sunny Tucson to overcast Boston was overwhelming. When she sought help, it was claimed her concerns were due to “going away for school,” or “missing her family,” adding frustration to the experience. Understanding it was due to seasonal issues and getting proper treatment made all the difference.
If you start to notice a pattern in your mood, energy levels, appetite, etc., linked to seasonal changes, ask your provider or advice on how to approach the issue. Don’t ignore the issue, as S.A.D. is not just the “blues,” it is a specific type of depression and should be addressed.
Sources:
-theatlantic.com/health/archive/2017/03/seasonal-affective-disorder-mosaic/519495/
-mayoclinic.org/diseases-conditions/seasonal-affective-disorder/in-depth/seasonal-affective-disorder-treatment/art-20048298
-mayoclinic.org/diseases-conditions/seasonal-affective-disorder/symptoms-causes/syc-20364651
-psycom.net/depression.central.seasonal.html
-oxfordmedicine.com/mobile/view/10.1093/med/9780199544288.001.0001/med-9780199544288-chapter-010https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2686645/