We all have times when we feel a little down, but for many people, the symptoms of depression are more persistent and debilitating. Seasonal affective disorder (SAD) is a type of depression that typically occurs during the fall and winter months. While SAD can occur in any age group, it’s most common in people ages 30 to 50.
Researchers believe SAD is characterized by a distinct pattern of symptoms. People with the disorder experience depressed mood, low energy, sleep problems, appetite changes, and anxiety or trouble concentrating. For some people, symptoms may also occur in spring and summer. Treatment for SAD can include light therapy, antidepressant medication, or a combination of the two.
Exposure to light can trigger the pineal gland to release melatonin, producing a feeling of well-being. Less exposure to sunlight and artificial light during the fall and winter seasons may decrease serotonin levels, which affects mood. High levels of cortisol, a stress hormone, may inhibit melatonin production.
Changes in daylight levels during the fall and winter seasons are thought to prompt the release of melatonin. A decrease in melatonin production, in turn, may prompt the release of cortisol, which affects mood. Changes in levels of serotonin, norepinephrine, and dopamine, neurotransmitters that play a role in mood, may also affect mood.
SAD usually occurs in the fall and winter months and typically disappears when spring and summer arrive. The cause of SAD is unknown, but research has linked SAD to changes in the body’s internal clock.
The body’s internal clock regulates many daily functions, including sleep, body temperature and hormone levels. When your body’s internal clock is out of sync with the changing seasons, it can trigger SAD. People who feel depressed in the fall and winter months — regardless of their time of year — should consult a doctor. The symptoms of SAD typically disappear as the days get longer.