Seasonal depression, also known as seasonal affective disorder, occurs at the same time each year, typically beginning in late autumn or early winter and ending in late spring or early summer. It is not simply winter depression or cabin fever. A rare seasonal affective disorder, summer depression, begins in late spring or early summer and ends in autumn. Modern medical research suggests that the primary cause of seasonal depression is reduced sunlight exposure in winter, which can cause the body's biological clock to misalign with the shortened daylight hours, leading to circadian rhythm and endocrine disorders, resulting in mood and mental disturbances.
Seasonal depression, also known as seasonal affective disorder, is a type of depression (or melancholia). It occurs at the same time each year, typically beginning in late autumn or early winter and ending in late spring or early summer. It is not simply winter depression or cabin fever. A rare seasonal affective disorder, summer depression, begins in late spring or early summer and ends in autumn.
Symptoms
People with seasonal depression experience common symptoms of depression: sadness, anxiety, irritability, loss of interest, decreased social activity, and difficulty concentrating. Characteristic symptoms include excessive sleepiness, increased sugar cravings, increased appetite, and weight gain.
The main symptoms of winter depression are:
- Fatigue
- Excessive sleepiness
- Lack of energy
- Increased appetite
- Difficulty concentrating
- Desire for solitude
The main symptoms of summer depression are:
- Weight loss
- Sleep disturbances
- Loss of appetite
4%-6% of people with seasonal affective disorder have experienced milder episodes of the winter blues. Women account for three-quarters of these patients, and the majority are between the ages of 20 and 40. Children, adolescents, and the elderly can also be affected.
In high latitudes, where seasonal changes are more pronounced, the prevalence of seasonal affective disorder is relatively high. An estimated 1% of the population in Florida suffers from seasonal affective disorder, while the rate in Washington, D.C. is 4%, and in Alaska, it's as high as 10%.
Causes
The exact cause of seasonal affective disorder is unknown, but variations in sunlight duration are a contributing factor, as it is influenced by latitude. One theory is that the shorter hours of sunlight in winter slow the biological clocks that regulate mood, sleep, and sex hormones.
Another theory suggests that seasonal affective disorder (SAAD) affects the chemical signals that transmit information in the brain, and sunlight exposure can restore balance.
It can be difficult to diagnose SAD yourself, so it's best to see a doctor for comprehensive testing. Sometimes, physical problems can trigger depression. Other SAD symptoms may be part of another mental health issue.