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Health A to Z  —  2 minutes

Seasonal depression

February 21st, 2019
Raymond Lepage, PhD, Doctor in Biochemistry
Raymond Lepage, PhD, Doctor in Biochemistry
Science popularizer

For most people, winter blues are only a short-term problem, but for one in five, the onset of winter, with its colder temperatures and reduced sunshine, corresponds to a deeper malaise, a form of depression referred to as “seasonal” or “seasonal affective disorder” (SAD).

To be depressed is to be reduced to seeing only the negative sides of life to the point that it prevents fulfillment of obligations (family, professional and others). Seasonal depression is a psychological disorder that requires attention. It is only one of the manifestations of depression, along with major depression, post-partum depression and bipolar syndromes.

There are also psychological symptoms, such as acute sadness that tends to increase in the evening, loss of interest in usual activities, lower self-esteem accompanied by feelings of guilt or failure, as well as difficulty concentrating and making decisions. In rare cases, seasonal depression can even lead to suicidal thoughts. The precise causes of seasonal depression are unknown, but some of the symptoms may be caused by the pineal gland, a small structure in the brain that serves as our biological clock. When daylight decreases, the pineal gland reacts by secreting more melatonin, a hormone known to cause drowsiness and fatigue.

Although melatonin levels can be measured in the laboratory, diagnosis of seasonal depression and other forms of depression is based exclusively on case analysis by a psychiatrist, psychologist or another health professional who has the required expertise. Apart from the rather useless melatonin testing, there is no laboratory test or imaging procedure that enables us to confirm a diagnosis of seasonal depression. However, a health care professional may prescribe certain tests, such as a complete blood count or thyroid panel, to rule out other common causes for some of the patient’s symptoms.

The treatment of seasonal depression is based on psychotherapy and the use of antidepressant medications. Since the effect of reduced daylight on the pineal gland is at least partially responsible, exposure to natural light or a light therapy lamp appears to be an appropriate option. Light therapy consists of 30 minutes of exposure, often daily, to light that resembles sunlight. It can be done at a specialized practice or at home with an approved device. In all cases, you must ensure that the device does not emit infrared and ultraviolet rays, which pose a greater danger to health.