Many years ago in London, I came across an Egyptian medical student. While I was dreading the coming of the British winter, for Mariam who came from a country with midsummer temperatures of around 45˚-50˚C, the idea of cold and wet weather seemed delightful and refreshing. Mariam spent her first summer in London enjoying the occasional shower, breeze and warm sunshine. Soon the cool breeze gave way to cold wind and heavy rain. Day after day, the cloudy and rainy weather became more frequent. Finally a bitterly freezing winter arrived. Mariam’s smile changed to a frown and gradually to a sulk. She became irritable and appeared to have lost the motivation to get up and head for college or work.A couple of friends realised her anxiety and tried to take her mind off the British weather by suggesting going on a short trip up north. However, the closer they got to Scotland, the more depressed and blue she got. None of the breathtaking views and landscapes of Caledonia seemed to interest her. She could not understand what was happening. Little did she know that the weather was the culprit. In fact, she was suffering from a disorder known as SAD (Seasonal Affective Disorder). The Office for National Statistics estimates that seven per cent of the British population is affected by SAD, with around 17% of individuals suffering from a milder form of this condition known as Subsyndromal SAD which has similar effects but on a milder scale. Seasonal Affective Disorder is a mood disorder that happens at the same time each year. It is a type of depression that has a seasonal pattern and that is why it is also called winter depression or winter blues. Symptoms of this disorder usually begin in autumn and get more severe towards the winter, peaking in January and February. The symptoms gradually improve in spring. This disorder is categorised as 1) Unipolar depression; where the patient experiences depressive symptoms, or 2) Bipolar depression; when depressing periods (lows) are followed by manic periods (highs) where one feels happy, energetic and much more sociable. Symptoms of SAD are much the same as those of depression and include irritability and despair, lack of energy, loss of concentration, increased appetite and anxiety. However with bipolar depression the patient may experience periods of elevated mood, hyperactivity, agitation, rapid thoughts and rapid speech. Although scientists know that SAD is linked to the shorter days of the year – when the body receives less exposure to sunlight – its exact cause is still a mystery. Most explanations revolve around changes in hormone levels. Hormonal changes Hypothalamus is a gland in the brain that when exposed to light regulates many bodily activities, including sleep and appetite. It also regulates the circadian rhythms or the body’s internal clock.
Exposure to light in the day balances the amount of some internal hormones including melatonin and serotonin. Melatonin is an internal hormone produced by a small gland in the brain called the pineal gland that regulates sleep. In daylight, the pineal gland gets a message from the hypothalamus to stop producing melatonin but when it becomes dark the pineal gland begins to produce melatonin to induce sleep.
What happened to Mariam, the Egyptian student, was that during the shorter and darker winter days, the amount of melatonin produced in her body increased and made her feel drowsy, moodier and less energetic. Serotonin is another internal hormone that affects mood and sleep. The amounts of Serotonin can increase with the amount of daylight. The more we are exposed to light, the more Serotonin is produced. When the amount of Serotonin is less than average the symptoms of SAD appear. Periods of exposure to light followed by a period of darkness creates a hormonal and behavioural rhythm in the body called the circadian rhythm. Lack of sunlight during the day may muddle up this subtle timing. People who are living far north or south of the equator are more likely to be affected by SAD. Patients such as Mariam are normally recommended one of the treatments mentioned below together with a prescription of medicines. Light Therapy Light therapy is the first in line of treatments. It is fast responding with few side effects. Specially designed light boxes with a very bright high lux light are placed in front of the patient. The patient sits in front of the light source but not staring at the light directly. This therapy is more effective if started in early autumn before the symptoms appear. The light coming from the light box resembles sunlight and encourages the brain to reduce the production of Melatonin and increase the production of Serotonin. Sitting in front of a large high lux light box (light intensity is measured by lux), for 45 minutes a day and taking one fluoxetine (Prozac, Sarafem) capsule daily soon made Mariam feel better and less gloomy. Vitamin D Deficiency Lack of Ultraviolet-B on the skin (normally associated with sun exposure) reduces the level of vitamin D. Increasing the body’s intake of vitamin D by taking supplements is an alternative to bright light treatment. Antidepressants Drugs used for depression can also be used for severe forms of SAD. Some specific anti-depressants increase the levels of serotonin in the brain and lift one’s mood. It may take 4-6 weeks for these drugs to take full effect. Cognitive Behavioural Therapy As with any other form of depression, cognitive behavioural therapy is an option which helps the patient to reconsider h/her reaction to the extreme mood swings. Physical Exercise This has been shown to be an effective form of depression therapy, particularly in addition to other treatments. Adding twenty minutes of exercise to a treatment usually helps the patient to recover quicker.