Saturday 24 March 2018

Don't be afraid of the dark

Patricia Casey

We've had the Presidential election and the drama that ranged from charges of airbrushing to accusations of criminality.

We've had the torrential downpour that flooded our capital, closed our transportation and sadly cost lives. And now we have just reversed our clocks by one hour. No wonder our moods are fluctuating.

The 'falling back' of our clocks, as it is colloquially known in the United States, reminds us that winter is here and that dreary months pave the layout of our lives until well into the New Year.


It is the time when seasonal affective disorder may again rear its head in those who have this condition. Also known as SAD, it is an uncommon disorder and is found in less than one per cent of those consulting general practitioners.

However some information sites on SAD describe higher rates, of up to eight per cent in the general population. Many of these prevalence studies have been conducted using self-scored questionnaires rather than face to face interviews.

In general, milder forms of the condition are most common among women while in men the severity seems to be greater, although the frequency is lower.

Studies from Canada, especially, demonstrate that when clocks shift backwards the incidence of depressive illness increases, probably mediated by the effect on sleep. It is found in both hemispheres, especially in northern latitudes and is almost unknown in those living within 30 degrees north or south of the equator.

Changes in the amount of light to which we are exposed are said to bring about alterations in the amount of melatonin we produce. This is a substance that induces sleepiness by night and it is switched off during the day so that we become active.

In those with SAD, daytime levels of melatonin are high so that sleepiness and a desire to hibernate are common. So our body clock, called the circadian rhythm, shifts and we become wakeful at night and sleepy by day.

In addition other hormones such as adrenaline, cortisol and thyroid hormone which ordinarily are reduced by day and increase during those hours further compounding the alterations to our natural daily rhythms.

As well as SAD, more modest changes in mood are common when the hours of daylight shorten. However, these are not accompanied by the cravings for chocolate or the desire to stay in bed and sleep that characterise SAD.

So these shifts do not amount to a disorder that needs treatment. Indeed feeling that the best part of the day is over when we leave work can itself have a mood-lowering effect as can the inactivity that is associated with long hours of darkness.

The opportunities to walk in the fresh air or to play football are greatly diminished and while the gym might beckon, for many it holds less attraction than the alternatives provided by nature.

Emotional reactions, such as these, to wind, rain and darkness are common and should not be regarded as anything but understandable responses that are unwelcome but not pathological.

However the effects of increasing darkness and of artificial light on melatonin may also play a role in these more common experiences of despondency that the winter months bring.


People with SAD need professional help that may include light therapy and/or antidepressants. Those of us experiencing gloom and despondency, not amounting to illness, but deeply felt, can reduce their intensity rather than fatalistically accepting five months of misery until the clocks spring forward in March.

We can schedule activities during daylight hours, as light will help boost our melatonin production. Exercise also has this effect but if it is impossible or impractical, using the gym is a good alternative.

We should avoid the temptation to become night owls as this will disrupt the wake/sleep cycle and our body clock more generally.

Mood shifts such as these provide the best evidence that there is a mind-body connection driven by our environment. In so far as winter is concerned, at least we have a degree of control over our reactions to its dreariness.

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