Summer is all about sunshine, beach trips, and #RoséAllDay—three months of nothing but fun...right? Actually, for a small percentage of people, the warmer months are the hardest time of year, as the overload of heat and light triggers a seasonal depression.
You've probably heard of seasonal affective disorder, or SAD, where some 20 percent of the population feel more depressed in the winter thanks to less light. Well, there's also a kind that hits people in the warmer months, called reverse seasonal affective disorder, or summer SAD.
Summer SAD is vastly under-researched compared to the winter variety, says Norman Rosenthal, M.D., psychiatrist, and author of Winter Blues. In the mid '80s, Dr. Rosenthal was the first to describe and coin the term "seasonal affective disorder." Shortly after, he noticed some people were presenting a similar form of depression, but in spring and summer rather than fall and winter.
Here, what you need to know:
What Exactly Is Summer SAD?
While we don't have very much hard data on summer SAD, we do know a few things: It affects less than 5 percent of Americans and is more common in the sunny, hot south than the north. And just like with all forms of depression, women are more likely to be afflicted than men.
As for what causes it, there are a few theories: For starters, all people face different challenges adapting to a shifting environment, explains Dr. Rosenthal (think: trying to get warm in a cold room, overcoming jet lag faster). "Some people with depression in the winter need more light and if they don't get it, this can disturb their internal clock and/or leave them with a deficit of crucial neurotransmitters, like serotonin," he explains. "In the summer, an overload of heat or light similarly disrupts some people's body clock or overwhelms their adaptive mechanisms to deal with the increased stimulus. In either case, you aren't able to rally the protective mechanisms to make you tolerate the change."
This is an interesting idea considering most of us tend to think sunlight is one of the strongest health elixirs we have. After all, study after study shows getting outside more can decrease depression, decrease anxiety, and boost vitamin D levels, thereby improving general health and happiness. "The general concept is sunlight is good and darkness is bad, but that's over-simplistic. We evolved with both the light and the dark, so we need both of these phases of the day to get our clocks working as they should. If you have too much of one or can't adapt to one, then you develop SAD," Dr. Rosenthal explains.
Kathryn Roecklein, Ph.D., a psychology professor at the University of Pittsburgh who studies circadian rhythms and affective disorders, puts forth a slightly different interpretation of the condition: "There's a theory of depression which suggests when you are unable to participate in the activities you normally enjoy, you receive less reward from your environment. The way we understand summer SAD is that it may follow the same reasoning: If the weather is so hot it prevents you from engaging in activities you enjoy, like running outside or gardening, then missing that reward can cause seasonal depression."
Other theories include the idea that it may involve a sensitivity to pollen—one preliminary study in the Journal of Affective Disorders found summer SAD sufferers reported worse moods when the pollen count was high—and that what season you're born in may even make you more susceptible.
However, Dr. Rosenthal says there's surprisingly no evidence to suggest conditioning comes into play—you're not any less likely to develop summer SAD if you grew up in a sunny state compared to growing up in overcast. (However, you might notice the mood shift more if you move from the north to the south, he adds.)
What Does Summer SAD Look Like?
In both seasons, SAD has the same symptoms as clinical depression: low mood and loss of interest and engagement in things you usually enjoy. The only difference between SAD and clinical depression is that the seasonal kind starts and stops at predictable times (spring to fall or fall to spring), Roecklein says.
The warm-weather variety, specifically, is triggered and exacerbated by either heat or sunlight, says Dr. Rosenthal. And though they are two sides of the same coin, summer SAD presents different symptoms than the winter kind. "People with winter depression are like hibernating bears—they slow down, oversleep, overeat, gain weight, and are generally sluggish," he says. On the flip side, "someone with summer depression is full of energy but in an agitated way. They usually don't eat as much, don't sleep as well, and they are at greater risk of suicide than their winter counterparts." Some people even report palpable reactions, and describe the sun slicing through them like a knife, he adds.
How Do I Know If I Have Summer SAD?
If you feel more down in the summer, consider this: Are you more agitated when it's really hot or sunny out? Do you feel significantly happier once you hit air conditioning and indoors? Does bright light upset you even in the winter, like when the sun is reflecting off the snow? If so, you may have SAD.
If so, the first step is going to a therapist. Roecklein says you'll be hard-pressed to find one who specializes in SAD, but someone who treats general depression can help. There are a few different treatment options: Antidepressants have been shown to help, as does avoiding the triggers (heat and light). Roecklein says she's also seen patients make great progress by finding ways to engage in the activities summer is making them missing out on, like running indoors on a treadmill with a video of nature, or starting an indoor garden.
There are a few in-the-moment fixes that can help, too, Dr. Rosenthal adds: If heat is the problem, taking a cold shower, staying inside, and keeping the AC low can all provide some relief. If light is a trigger, wearing dark glasses and hanging dark curtains can help.
Roecklein also suggests SAD sufferers look into cognitive behavioral therapy (CBT), which focuses on changing the way you feel by changing the way you frame a situation. Why? "There's definitely a concept that summer is awesome and the best time of year, and that can make it hard when you feel more depressed during these months," she adds.