Yeah, Seasonal Affective Disorder is Real

Healthy Aging

Keeping darker days from being, well, so dang dark

As days start getting shorter and nights longer, 1 in 10 of us will start experiencing the symptoms of Seasonal Affective Disorder (oh so appropriately called, SAD). This week, we’re covering the symptoms of seasonal affective disorder, the most recent science on what causes it, and most importantly – what we can do about it.

I’m pretty sure I have Seasonal Affective Disorder. But what is it, again?

Seasonal affective disorder (aka, SAD) is a condition that arises in fall and progresses through winter. Come spring and summer, seasonal affective disorder disappears. As described by Rosenthal et al., this condition often includes the following:

• Over sleeping, but with less slow-wave sleep
• Over eating, with extra carbohydrate cravings
• Prominent fatigue (yawn, being super tired)
• Episodes of sadness or depression

If you just checked off several items on this list, you’re not alone. In his review, Magnusson showed that most adults experience some amount of these changes during winter, and this is called “subsyndromal SAD”.

What causes SAD?

As with anything that affects our mood and behavior, there is no single thing that causes this winter gloominess. That said, R.D. Levitan shares the following top contributors to SAD:

• An out-of-whack circadian rhythm, which is our biological clock that responds to changes in light and dark
• Imbalanced melatonin, a hormone our brain makes based on light-dark cycles
• Low levels of monoamine neurotransmitters, including serotonin, norepinephrine, and dopamine

Based on how much each of these components plays a role in an individual can help guide which treatments may work best. But, if we had to cut to the chase (which is likely why you read Science Says!), the common link is… light. Specifically, the need for good ol’ fashioned daylight.

Sorry, Northerners. Evolution has been too darn slow…

The more sunshine you get, the less likely you are to have severe seasonal affective disorder. Numerous studies, including those reviewed by Magnusson, have shown that the further north one lives, the higher the prevalence of SAD.

Levitan explains that, since homo sapiens (fancy name for, us) primarily originated at the equator, our ancestors did not have to deal with major shifts in the amount of daylight they received throughout the year. As we expanded to living away from the equator, we did not evolve quickly enough to effectively adapt to big changes in daylight doses. Enter, SAD.

…or maybe you’re just better survivors.

Another explanation for SAD provided by Levitan, is called the “seasonal thrifty phenotype”. Here, it is proposed that we crave carbs, gain weight, and sleep more in the winter to increase our likelihood of survival in the dark, snowy months. Yeah, like hibernation and bears. Except with macaroni and cheese and episode binge-watching.

Some solutions? Walk in the sun while talking to friends. 

In their review, Jupe et al. cover the latest scientific support for various treatments of SAD. This includes the following:

• Maximizing your daylight exposure
• Regular exercise
• Managing stress
• Light therapy (light boxes that simulate sunlight exposure)
• Talking therapies
• Selective serotonin reuptake inhibitors

Here, Jupe et al. conclude that, as well as getting benefits from any or all of the above, light therapy effectively improves symptoms of SAD within a week. Before searching for “light boxes”, however, work with your physician to understand what may work best for you… and which light therapies provide true hope vs. hype.