AS THE YEAR ENDS and winter sets in, many people find themselves struggling with depression. However, when spring comes, the depression lifts and a person is fine—until the next fall/winter season. This seasonal depression is commonly called “the winter blues.” Its scientific name is seasonal affective disorder (SAD; “affective” is another word for “mood”).
In addition to depression, other SAD symptoms are tiredness, lack of energy, craving for sugary foods, weight gain, delayed sleep and wake times, sleeping excessively, and/or difficulty awakening to start the day. SAD symptoms can range from mild to severe.
Why SAD occurs in some people with the onset of winter continues to perplex scientists. However, some research indicates that reduced light levels in the fall and winter may impact the levels of certain brain chemicals such as melatonin and serotonin, which are involved in mood.
Melatonin (pronounced “MELuh- TOE-nin”) is a brain chemical that causes a person to go to sleep. On a daily basis, melatonin levels normally rise as evening progresses (i.e., as light levels decrease) and fall during the daytime. On a seasonal basis, melatonin levels are generally higher in the fall and winter when nights are longer and lower in the spring and summer when daylight is longer. Melatonin has been linked to depression. Thus, with the longer nights of fall and winter, people with SAD may be more prone to winter depression because of the higher melatonin levels.
Serotonin (pronounced “SEH-roh-TOE-nin”) is a brain chemical that affects mood. Scientists believe that low levels of serotonin in the brain contribute to depression. Lower light levels in the fall and winter are associated with lower serotonin levels. Thus, seasonally lower levels of serotonin may contribute to winter depression.
Many people with mild SAD symptoms find bright light therapy helpful. Bright light therapy involves brief exposure (e.g., 20-30 minutes) to light emitted by a special lightbox at an intensity that is brighter than that of the sun. The intense light causes a dramatic drop in the melatonin level, which may help alleviate winter depression. However, bright light therapy may not be appropriate for people with certain conditions (e.g., bipolar disease, glaucoma, cataracts, circadian rhythm disorders).
For people with more problematic SAD symptoms or who should not use bright light therapy, taking antidepressant medications such as selective serotonin reuptake inhibitors (SSRIs; drugs such as fluoxetine [trade name: Prozac], paroxetine [Paxil], or sertraline [Zoloft]) during the winter months may be helpful. SSRI drugs allow serotonin levels to increase in the brain, which may then alleviate depression.
Diagnosing SAD can be difficult because other conditions have similar symptoms. However, if depression occurs at a similar time each year for at least two years, and the period of depression is followed by a period without depression, undiagnosed SAD could be the cause.
If you suspect you have SAD, discuss your symptoms with your doctor, who may order tests to rule out other disorders that can mimic SAD (e.g., bipolar disorder, hypothyroidism, or a circadian rhythm disorder). Once other causes for depressive symptoms are ruled out, your doctor may try bright light therapy (as stated earlier, it is not appropriate for everyone) or drug therapy. With appropriate treatment, wintertime does not have to be the SAD time of year.
Regina Patrick, RPSGT, RST, is a freelance writer/editor and a registered sleep technologist. She has been involved in the sleep field for more than 30 years.
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