Seasonal affective disorder strikes some in the summer. Climate change may make it worse.

Story at a glance

  • As climate change brings on hotter and hotter summers, health experts worry a type of depression called summer seasonal affective disorder could become more common.

  • People with the condition often grow agitated and irritable as the weather heats, and sometimes experience — or act on — suicidal thoughts.

  • Health experts also fear that symptoms of the condition could become worse in those that already have it —potentially causing a rise in suicides.

When spring comes and daylight hours grow longer, Greg Flick, a high school science teacher in Syracuse, N.Y., starts to feel depressed.

“I can appreciate the beauty of it and the temperatures aren’t bad, but I know what’s coming,” said Flick who suffers from summer seasonal affective disorder (SAD), a type of depression triggered by the heat, humidity and long hours of sunlight that come during the warmer months of the year.

Flick has dealt with the condition for 50 years, he said, and has noticed his symptoms have worsened as the summers have grown hotter over time.

“I’ve become less tolerant of the heat, and I think that’s both a function of my physiology and I think it’s also a function of climate change,” he said.

Health experts fear increasing temperatures and amounts ofairborne pollen linked to climate change could make summer SAD more common or worsen symptoms among those who already suffer from the condition, potentially putting them at greater risk of committing suicide.

“I have little doubt that climate change will make a huge difference, both to the number of people who are going to suffer from summer SADand to the severity of those people who already feel that they’re having summer SAD,” said Norman Rosenthal, a psychiatrist at the Georgetown University School of Medicine who, along with a team of colleagues, first identified season affective disorder in 1984.

Thomas Joseph Doherty, a psychologist in Portland, Ore., who specializes in the psychological impacts of climate change, agrees that it will most likely worsen summer seasonal affective disorder symptoms, given that rising global temperatures are hurting all aspects of health.

A small percentage of Americans currently have seasonal affective disorder, with about 5 percent of adults experiencing the condition during the winter and 1 percent during the summer months.

Summer SAD and its more widely known winter counterpart are both mood disorders set off by changes in the seasons, but the triggers for the conditions differ, as do the ways their associated depressive symptoms present themselves.

Winter SAD is mainly triggered by reduced sunlight exposure as days shorten during the colder months, while summer SAD is set off primarily by heat and humidity, according to Kelly Rohan, a psychology professor at the University of Vermont who studies seasonal affective disorder.

“The assumed triggers are heat and humidity, so with global warming, we certainly have more of that, so it would stand to reason that we would see more cases,” she said.

Extended daylight hours can cause summer SAD symptoms as well, according to Rosenthal.

There is also some evidence suggesting that pollen might trigger the seasonal mood disorder. One 2019 study examined seasonal mood changes among members of an Old Order Amish community in Lancaster, Pa., and found a connection between pollen exposure and worsened mood during the summer.

Climate change has put humans at risk of being exposed to more pollen since warmer spring temperatures and increased carbon dioxide in the atmosphere can cause some plants to release the grains earlier.

People who become depressed from winter SAD tend to be more lethargic than those who experience summer SAD.

“With winter SAD people are usually slowed down, sluggish and they compare themselves to hibernating animals, whereas with summer SAD they are often agitated and irritable,” said Rosenthal.

This is the case for Flick, whose springtime depression manifests as extreme irritability once the weather becomes warmer.

People who suffer from winter SAD and summer SAD are both likely to have thoughts of suicide, Rosenthal told The Hill. But, he said, since those who experience the condition during the hotter months are more agitated, they’re more likely to act on those thoughts.

There is a common misconception that suicides increase in the winter, especially around the holidays, but research shows the numbers spike in April, May and June.

“It’s potentially a very severe syndrome if it’s bad … if you’re agitated, you’re more likely to do impulsive things,” Rosenthal said.

Though health experts know the triggers for winter and summer SAD, it is not entirely clear why changes in light and temperature can so profoundly affect some people.

Rohan said some research suggests genetics play a significant role in who develops seasonal affective disorder and that in the case of winter SAD, a disruption in the circadian clock might also play a role.

More research needs to be done to fully understand what predisposes some people to the conditions over others.  But experts do have recommendations for numerous ways to help those who do suffer from them to cope.

Rosenthal encourages people with summer SAD who are bothered by the heat to take long cold baths or showers and to stay indoors where there is air conditioning as long as possible.

Flick, who suffers from insomnia because of the summer light, uses blackout drapes in his bedroom and routinely wears a sleep mask to bed to ensure that the early rising and late setting sun doesn’t disrupt his rest.

When it comes to keeping cool, Flick will regularly retreat to air-conditioned rooms and decline invitations to social gatherings that require him to be outside and under the sun.

Sometimes, however, he will allow himself to express his general feelings of frustration as a way of coping.    Years ago, Flick said, he gave himself permission to “completely lose it” five times every summer.

“I mean stomping my feet, really crabbing five times,” he said. “I husband these very carefully because I don’t want to use them up … I think it’s actually mindfulness at its core.”

People who suffer from summer SAD, or think that they might, and find that simple coping methods aren’t helping enough should seek professional help from a psychologist or psychiatrist, Rosenthal added.

Therapy could be beneficial in some cases, as could medication. “There is no reason to believe that antidepressant medication wouldn’t be of some value,” he said.

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