What is Seasonal Affective Disorder (SAD)?
SAD was first acknowledged before 1845 but was not officially named until the early 1980s. As sunlight has affected the seasonal activities of animals (i.e, reproductive cycles and hibernation), SAD may be an effect of this seasonal light variation in humans. As the seasons change, there is a shift in our “biological internal clocks” or circadian rhythm, due partly to these changes in sunlight patterns. This can cause our biological clocks to be out of synch with our daily schedules. The most difficult months for SAD sufferers are January and February with younger people and women being more prone.
Symptoms include:
• Regularly occurring symptoms of depression (excessive eating and
sleeping, weight gain) during the autumn or winter months.
• Full remission from depression during the spring and
summer months
• A craving for starchy and/or starchy foods
The possible cause of this disorder is melatonin, a sleep-related hormone secreted by the pineal gland in the brain. This hormone may cause symptoms of depression and is produced at increased levels in the dark. Therefore, when the days are shorter and darker the production of this hormone increases.
Problems With Diagnosis
People who have lived near the tropics for part of their lives and then migrate to this country are more vulnerable to SAD symptoms. There is a view that people from different cultural backgrounds, whose symptoms show up differently, are sometimes misdiagnosed and wrongly told they have schizophrenia or manic depression.
SAD can begin at any age, most commonly between 18 and 30, with more people developing it before the age of 21 than after. No-one really knows what triggers it, but in a survey of people with SAD, it was linked to events such as childbirth, hysterectomy or other hormonal upheavals. Of those who took part in the survey, 14 per cent said it had been triggered by a major loss or bereavement and 11 per cent by serious illness, both of which are common triggers of depression.
It’s thought that twice as many women as men have SAD, but it’s difficult to get an accurate picture. Characteristically, men find it harder to admit to depressive symptoms and are more likely to try to find relief in alcohol and drugs than to go to the doctor. But more men are now recognising their symptoms and seeking treatment.
Children
Children with SAD tend to be irritable, badly behaved and sleepy (finding it difficult to wake up or stay awake), and this may earn them the labels ‘lazy’ or ‘difficult’. If SAD is the cause, and goes undiagnosed, it can have a very negative effect on a child’s life and on their future.
Treatments for SAD include phototherapy or bright light therapy and have been shown to suppress the brain’s secretion of melatonin. Although, there have been no findings during research to definitely link this therapy with an anti depressant effect, many people seem to respond to this type of treatment.
The device most often used these days is a bank of white fluorescent lights on a metal reflector and shield with a plastic screen. For mild symptoms, spending time outdoors during the day or arranging homes and workplaces to receive more sunlight during the autumn / winter months may prove to be helpful.
One recent study found that an hour’s walk in winter sunlight was as effective as two and a half hours under bright artificial light.