Part 2

In my last article for Euro Weekly News, I began a brief exploration of Seasonal Affective Disorder (S.A.D) a condition affecting around 2% of the U.K population, with women more likely to suffer than men, and with a typical age of onset between 18 and 30.  SAD is directly related to the amount of sunshine available, but as with many psychological conditions, this may not be the only factor at play, where for example the likelihood of experiencing SAD increases where a close family member suffers.  We also looked at “sub-syndromal SAD”, affecting a larger, 10% of the U.K population, and itself producing symptoms ranging from problems with sleeping and eating, and tiredness and lethargy, but no actual depression.  However, at the other end of the spectrum, we looked at full-blown SAD, a major disabling illness, preventing a person suffering from it from functioning normally without medical and/or psychological treatment.  This time we will look at the causes of the condition. 

 We often forget it, but we humans are complex and finely balanced creatures. Disturbances in that balance in our external world, where we can be buoyed or battered by life, can impact our internal balance, our mood if you like, just as changes or imbalance in our internal world, whether naturally occurring through hormonal or other chemical change, or through the deliberate introduction of substances like alcohol, nicotine, caffeine or other “drugs”, affect our mood and then our behaviour.

SAD is caused by biochemical change - a move away from what is “normal” for us - in a part of the brain called the hypothalamus, due it is believed to the shortening of daylight hours and the lack of sunlight in winter.  The hypothalamus gland is a very small part of the brain, but its many functions all seem to be about regulation or achieving balance in our system. It is like our central control mechanism taking inputs from other organs and systems, and then making changes to regulate operation. It is known there is a strong link between this gland and the retina, and this may be why the reduction of light entering the body through the eyes is thought to impact the ability of the hypothalamus to achieve balance, or homeostasis.

Specifically, production of two chemicals that have a big impact on mood are affected by an absence of strong enough sunlight.  The first is melatonin, produced by the pineal gland, which tells our body clock it is night time and to close down for sleep. Daybreak and bright light tells the gland to cease production of melatonin and of course, if it doesn’t receive this trigger, we don’t wake up well, and as a consequence can’t shift a tired, lethargic feeling and one of needing more sleep. Think about getting out of bed for work or school in the dark on a cold winter’s morning in the U.K.  Everything becomes more of an effort, and we perceive situations and people from a different, often more negative perspective. We are more likely to be grumpy and short-tempered, and prone to accidents too.

Light intensity and quantity has also been linked to the production of serotonin, a chemical which acts as a neurotransmitter in the brain, facilitating the movement of electrical impulses across the brain- the carriers of thoughts, feelings and perceptions if you like.  The link between low serotonin levels and depression is well understood, again where it becomes difficult (or impossible for some) to concentrate and complete what they might at other times regard as simple and necessary tasks. Research has shown serotonin levels do increase with exposure to bright light, i.e. depression can be reduced or lifted in such situations.  Many of us include “the weather” as one of our reasons for leaving the U.K to live or spend the winter in Spain.  It would be interesting to carry out research to see if expats on the Costas suffer from a higher than average incidence of SAD or sub-syndromal SAD! 

In the final part of this series, we’ll look at ways of managing SAD.  As I said last time, if you are affected I would be very interested to hear from you – sharing knowledge is the way forward and it can be very comforting for people to know that they are not the only one feeling a particular way. Take care of yourselves, and thanks for reading.