Now that the days are shorter and darker, many people understandably feel a little miserable. But an estimated half a million of them aren’t just a little low — they have seasonal affective disorder (SAD).
And that means their malaise could last from around now until April, when spring is in the air again.
For up to 2% of the population, SAD is a seriously disabling psychiatric disorder that prevents them from functioning normally without medical treatment. Symptoms can include depression, extreme lethargy, sleep problems, overeating, anxiety, social problems, mood changes and loss of libido.
Most sufferers also show signs of a weakened immune system during the winter, and are more vulnerable to infections and other illnesses.
For a further 20% of the population, it’s a more mild, but still somewhat debilitating condition, called subsyndromal SAD or, more commonly, ’winter blues’. With this milder form of the condition, while there may be symptoms such as low mood, and sleep and eating problems, full-blown depression and anxiety tend to be absent or mild.
Symptoms usually recur regularly each winter, starting between September and November and continuing until March or April.
A diagnosis can be made after three or more consecutive winters of symptoms, which disappear in spring, either suddenly with a few weeks of hyperactivity, or gradually, depending on the intensity of sunlight in the spring and early summer.
While the exact cause of SAD is still unknown, it’s thought to be linked to a biochemical imbalance in the brain, due to the shortening of daylight hours and the lack of sunlight in winter.
One theory is that light stimulates a part of the brain called the hypothalamus, which controls mood, sleep and appetite. In people with SAD, lack of sunlight may prevent the hypothalamus from working properly, increasing the production of the hormone melatonin, which helps you sleep, and reducing the production of the hormone serotonin, a neurotransmitter thought to contribute to feelings of wellbeing and happiness. Lack of sunlight may also disturb circadian rhythms (the body’s internal clock).
Consultant psychiatrist Dr Aarohee Desai-Gupta says SAD patients tend to be sleepy with an excessive appetite, compared to people with typical depression, who lack an appetite and often can’t sleep.
While antidepressants and cognitive behavioural therapy (CBT) can help, she says bright light also works well. Light therapy, involving daily exposure to very bright light, at least 10 times the intensity of normal domestic lighting, has been shown to help in up to 85% of diagnosed SAD cases.
She points out there’s plenty that those with milder forms of the condition can do to help themselves.
This includes vigorous exercise, like brisk walking for 25-30 minutes a day, eating a healthy diet, rather than comfort foods like biscuits and crisps — that people with SAD often turn to — and getting outside during the day as much as possible.
“Exposing themselves to as much daylight as is available, by doing outdoor activities such as gardening, walking and cycling, will minimise the symptoms of seasonal affective disorder,” she stresses.
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