‘Tis the season of frigid air and overcast skies, where daylight and sunshine are in shorter supply.
For millions in the U.S., year after year, the coming Winter causes a disruption in mood and behavior. They experience depression. They oversleep, over eat, and/or retreat from social activities and obligations.
This isn’t just the winter blues we’re talking about.
Having difficulty functioning because of a change in seasons is termed seasonal affective disorder or SAD, a type of depression that occurs with a seasonal pattern. Winter-induced SAD is more common. There is also Summer-pattern SAD, which can cause individuals to experience insomnia, weight loss, anxiety, and violent behavior in the summer months.
So, how prevalent is SAD? And what are the risk factors for it? Also, how are African Americans prone to developing this condition?
With the December 21 Winter Solstice approaching, we answer those questions with these 8 facts about SAD that you should know:
SAD is not Prevalent in the General Population
The National Library of Medicine (NLM) states that seasonal affective disorder is only present in about 0.5 to 3% of the general population. The Cleveland Clinic estimated that it is 5%.
People with Existing Mental Health Conditions are More Prone to Seasonal Depression
This is especially true of individuals with depression and bi-polar disorder. The NLM reports that SAD affects 10-20% of people who already have major depressive disorder and an estimated 25% of individuals with bipolar disorder.
People with SAD tend to also have other mental disorders like attention-deficit/hyperactivity disorder (ADHD), an anxiety disorder, panic disorder or an eating disorder, states the National Institute of Mental Health (NIMH).
It Can Run in Families as Well
Seasonal depression is more common in individuals with close relatives who have mental health disorders like major depression or schizophrenia, says the NIMH.
SAD Can Happen at Any Age, but it Often starts in Young Adulthood
The typical age it starts is between 18 and 30 years old.
Women Are More Likely to Suffer from SAD
According to information cited by Mental Health America (MHA), four out of five people with seasonal depression are women.
The Further You Live from the Equator, the Greater Your Risk
No surprise here: Winter-pattern SAD is more prevalent in the Northern areas of the U.S., especially those with below average sunlight exposure, a critical risk factor for the condition.
Gathering Google Trends data from October 2020 to March 2021 and climate information from the National Oceanic & Atmospheric Administration (NOAA), CertaPet concluded that Alaska, Ohio, Minnesota, Montana, and Michigan were the states most susceptible to seasonal depression. That study also examined the level of sunlight exposure for all 50 states for the months of December, January, and February. Those five were at or near the bottom in sunshine rankings.
Brain Chemical Imbalance and Biological Clock Change Are Significant Risk Factors
Speaking of shorter daylight hours, people with SAD can experience a brain chemical imbalance from decreased sunlight during the Winter months, reports the Cleveland Clinic. Reduced sunlight can impact serotonin levels, the brain chemical that affects mood. That drop can lead to depression.
This One Risk Factor Makes African Americans Especially Vulnerable
Having low Vitamin D levels is also linked to seasonal depression. It just so happens that African Americans are at the highest risk of being deficient in this essential nutrient. Why? The melanin in our skin, which endows tone, can hamper our ability to synthesize the Vitamin D we get from the sun, according to Everyday Health. In addition, since serotonin also gets a boost from the nutrient, the lack of sunlight we receive in the Winter months can also lead to mood changes. What’s more, African Americans may possess different Vitamin D binding proteins, which work to carry the nutrient to various organs via the bloodstream.
“There are reasons to believe that African Americans not only need more sun to produce vitamin D, but they could well have different vitamin D binding proteins that might make them more vulnerable to variations in sunlight,” said Dr. David O. Meltzer, the chief of hospital medicine at University of Chicago Medicine.
It’s worth noting that Vitamin D deficiency can lead to other health issues like heart disease, cancer, and osteoarthritis.