Mind and meaning: 'tis the season to be suffering from SAD
October is upon us and now is the time when those with seasonal affective disorder (SAD) are likely to notice the recurrence of their depressive symptoms. The summer months, free from the unpleasantness of fatigue, low mood and the lurking, creeping depression and tearfulness, are over, and the cravings for carbohydrate-laden foods and for sleep are raising their heads again.
Despite the food cravings, appetite overall is reduced and there may be weight loss. If this diagnosis hasn't been made, many will misattribute these symptoms to the understandable realisation that dark days, long nights and cold weather are upon us.
What distinguishes SAD from the predictable low mood that most experience at this time of year is its persistence and unvarying severity from day-to-day.
The periods of joy and hope are scarce and short lived, while the gloom seems like an enveloping force.
Because of the incapacity caused by these symptoms, many are too exhausted and disinterested to go to work or socialise.
Typically the symptoms disappear in or around March followed sometimes by a brief period of elation and reduced sleep. While this may seem a consolation, the six or so months of drudgery and even despair, not to mention social withdrawal, are overwhelming. It is for this reason that SAD comes to the attention of doctors.
SAD occurs mainly in women, who comprise 80pc of sufferers. Studies show that it is prevalent in roughly 1-4pc of the population.
Most are under 40 when it comes to medical attention, but the usual age at which the symptoms first become apparent is between 18 and 30.
It is found among those living in both hemispheres, but it is almost unknown in those who live within 30 degrees north or south of the equator.
Light therefore seems to be a
crucial element in its causation, although it is not the only important factor since there is frequently a family history of depressive illness or of alcoholism.
The hormone melatonin, secreted by part of the brain known as the pineal gland, is thought to be involved in causing this condition.
One way to attempt to combat SAD is to take a winter sun holiday and, if possible, activities should be scheduled by day, so as to coincide with any sunlight that is available.
Exercise is also helpful since it boosts melatonin. Those working in environments that do not have any natural light may also be vulnerable to SAD and employers should try to make accommodations for this.
There is considerable evidence that light therapy does work in a proportion of those with SAD. The first experiment using this treatment was carried out in 1984. The amount of time for which one must sit beside light varies from individual to individual, but averages about one to two hours.
The wattage of the light is 10 times higher than the usual light and it requires a special light box which can be purchased from a medical supplier. If these strategies fail, the use of antidepressants during the risk period might be necessary. They can usually be discontinued in late spring.
SAD is unusual in that the symptoms differ in the pattern of symptoms from those of major depression.
One major theory for explaining SAD involves the "circadian rhythms" of the body. This term describes the fact that bodily functions follow a set pattern throughout the day.
It is thought that this internal clock is disrupted in SAD, causing a physiological impact and associated effects on appetite, mood, sleep and so on.
Melatonin plays a crucial role in the body clock mechanism. As light levels decrease in the evening, the pineal gland begins producing melatonin. It is a hormone whose main function is to induce sleep and to transmit the sleep message to various physiological systems in the body.
Then at dawn, bright light shining into the eye triggers the pineal gland to switch off the production of melatonin and removes the desire to sleep.
It has been found that this switch-on-switch-off mechanism is disrupted in those with SAD.
Serotonin is also linked to melatonin and is in fact converted into this substance. So the serotonin theory of depression generally, may be interlinked with the melatonin theory of SAD.
Whatever the explanation behind this fascinating condition, it is clear that treatment can be intermittent and those who have SAD should now prepare for it rather than waiting for the unpleasant symptoms to appear. Meanwhile, you can anticipate spring.
Health & Living