It’s easy to see why some people succumb to seasonal affective disorder (SAD) in the winter: cold, dark, damp, and gloomy weather can simply bring you down. So it may come as a surprise that you can get SAD in the summertime, too.
About 10 per cent of SAD sufferers will experience the condition during summer’s warm, sunny, and bright days, according to the National Alliance on Mental Illness.
“Studies done in Asia—China and India—where summer depressions are more common than winter depressions found that it was related to humidity and not just temperature and light,” Raymond Lam, professor and head of the Mood and Anxiety Disorders Program in the University of British Columbia’s department of psychiatry, tells Yahoo Canada. “It’s more of a problem in lower latitudes, in the tropical regions.”
However, summer SAD, sometimes called reverse SAD, can still strike people north of the border. And while some of its symptoms resemble those of winter SAD—including feelings of hopelessness or worthlessness, irritability, and trouble concentrating—others are quite the opposite of those that accompany the “winter blues."
“People with summer depression tend to have more problems with insomnia rather than oversleeping,” Lam says.
Other signs specific to summer-onset SAD, according to the Mayo Clinic, are weight loss, poor appetite, and agitation or anxiety.
In a study published in 1991, in the Journal of Affective Disorders, Thomas Wehr, a research psychiatrist at the National Institute of Mental Health, noted another contrast between the two types of seasonal depression: those who are depressed in winter are more likely to crave carbs.
Causes of summer SAD
Wehr and Washington psychiatrist Norman E. Rosenthal first identified winter SAD in 1984. After they received queries from people saying they suffered from summer depression, Wehr manipulated patients' body temperatures with cooling blankets, working from the observation that people with severe depression tend to have higher temperatures at night than healthy people. His patients felt better with a lower body temperature, but after the treatment was over and they went back out of the building into summer heat, their body temperatures rose, and the symptoms of their depression returned.
Despite that pair’s research, scientific study into reverse SAD is limited.
“We don’t have as much understanding of summer depression as winter depression,” Lam says, noting that theories abound.
Genetics are likely involved. According to the Canadian Mental Health Association, two-thirds of people with SAD have a family member with a major mood disorder.
Seasonal allergies could play a role. A 2007 study published in the Journal of Affective Disorders, although preliminary, found an association between self-reported cases of “mood worsening” during periods of high pollen counts. “In addition, participants who endorsed mood worsening when pollen count is high were more likely to meet criteria for non-winter SAD,” wrote lead author Alvaro Guzman, of the University of Maryland School of Medicine’s department of psychiatry.
An inflammatory response could be linked to depression. Studies consistently report that groups of individuals with major depressive disorder demonstrate higher levels of inflammatory biomarkers when compared with groups of non-depressed individuals, according to the National Institutes of Health.
“The broader issue [of depression] is sensitivity to environmental stressors,” Lam says. “Depression often stems from a series of stressors, whether they’re psychological or psychosocial or physical stressors; we know they will have an impact on vulnerability to depression….Seasonality is a very complicated aspect.”
Early research found that for some people, air conditioning made a difference for those experiencing reverse SAD, Lam says.
For others, antidepressants help, in part because they reduce body temperature.
Psychotherapy, or talk therapy, can help people develop coping strategies and identify and change negative thoughts and behaviours that can make you feel worse, according to the Mayo Clinic.
Regular exercise can help too, since it alleviates stress and anxiety and promotes better sleep.
While studies into of reverse SAD may not be abundant, there’s no denying this: don’t treat any signs or symptoms of depression lightly. There’s help for it, even on the hottest and sunniest of summer days.