Depression is not always a constant; there are some forms of depression that go through cycles and mirror the changing seasons. This type of depression is known as seasonal affective disorder, or SAD. According to the National Institute of Mental Health, SAD is not a separate depression but rather a depression that has a recurring pattern of beginning and ending at approximately the same time for individuals.

People have theorized what is the cause behind SAD. The Mayo Clinic offers three possible causes of SAD based on studies. First, your circadian rhythm (or biological clock) becomes o in the winter months due to the decreased amounts of daylight and your body can struggle to adjust to the limited sun exposure and incorrectly signal what time of day it is causing hypersomnia, feelings of depression and overeating.

Serotonin is a chemical largely responsible for our sleep patterns, social behavior, and memory. Again, the decrease in sunlight during late fall and winter months can lead to a drop in serotonin levels and cause an inability to regulate sleep patterns, social behaviors and memory.

Finally, the Mayo Clinic also sites melatonin as a reason individuals may su er from SAD. Melatonin is a hormone responsible for the sleep habits of our bodies, but melatonin is triggered to produce during nighttime hours (when it is dark outside) and then stop producing during daytime hours (when it is light outside), but due to the decreased amounts of sunlight in winter, the body
can overproduce melatonin causing hypersomnia.

In majority of cases of individuals who experience SAD, their episodes begin in the fall and continues into the winter months, generally subsiding in the spring or early summer. However, in more rare cases,SAD could also begin in the spring or early summer. In order to officially be diagnosed with SAD, this must occur two years in a row. The symptoms of SAD vary from individual to individual, but there are overall symptoms people can look for if they suspect they are experiencing SAD.

In general, some symptoms of SAD may include having low energy, hypersomnia (excessive sleepiness at all hours), overeating, weight gain, carbohydrate cravings and social withdrawal. Generally, the symptoms start o mild and become more severe as the seasons go on.

According to the National Institute of Mental Health, SAD is more often diagnosed in women than in men and occurs more frequently in younger adults than in older ones. Apart from gender and age, factors that may increase your risk of SAD could be family history, prior depression or bipolar disorder, and living farther from the equator where the summer days are long and winter ones are incredibly short. According the National Institute of Mental Health, only 1 percent of Floridians su er from SAD while 9 percent of New Englanders su er from SAD due to Florida being closer to the equator.

While SAD can often be self-diagnosed, if you find that you’re not motivated to do the things you usually enjoy doing for days at a time, you should see your doctor, especially if you are having trouble sleeping and your appetite has changed. They can con rm whether you are suffering from SAD and can recommend treatment. Various forms of treatment and therapy for SAD can include light therapy (where you work near a device that gives o bright light that mimics natural light), medication, psychotherapy or Vitamin D supplements.

If you’ve noticed any of the above symptoms in yourself or in someone close to you, it’s important not to brush it o as the winter or summer blues and go see your doctor. They can stop the disorder from getting more severe and help you be your normal self again.