Seasonal Affective Disorder – “the Winter Blues”(Observations of an Australian family living in Sweden)

Winter depression, or at least a ‘slump’ in mood’ during winter, was first described in the 6th century about the inhabitants of “Scandza” (Scandinavia). Such people have depressed mood, they sleep too much and they have very little energy.

Some people are more genetically predisposed than others to this effect within low-light environments, as not everyone is equally affected to the same low light conditions. But low light levels do seem to be critical in the development of this disorder, and exposure light seems to be extremely important in the treatment of this disorder.

The relationship of ‘hours of light exposure’ to what is now called Seasonal Affective Disorder (SAD) is best suggested by the increasing incidence of SAD which goes from about 1% in tropical climates to more than 10% in Nordic and other distant latitude countries. The incidence can reach as high as 20% in some regions.

In its most serious form (and untreated form) it may lead to suicide, but it also causes significant and potentially avoidable loss to overall economic productivity.

A possible evolutionary advantage of the slowing down of human activity during the winter months has been considered by some to have positive ‘survival value’ in human pre-history. There is limited food and limited energy to waste in winter, and sothe slowing down of human activity in winter may be akin to a ‘hibernation’ which occurs in other species. The predominance of SAD in women may have also had a role in regulating reproduction during these times.

In popular culture the term SAD is often misapplied to describe the normal shift to lower energy levels in winter, but the severity of symptoms of SAD are far far greater and they are usually disabling.

SAD was first described in modern times by a research engineer Herbert Kern who had apparently the disorder himself. In 1970 he devised a light box to regularize or regulate his light-dark daily body rhythms. This ‘light therapy’ appeared to work.

In 1984 another sufferer Dr Normal Rosenthal noted his own symptoms after emigrating from sunny South Africa to wintery New York. He did a simple placebo-controlled study using light exposure therapy, again with positive results. The originalscientific paper published by him was met however with considerable scepticism before it was finally accepted as a true psychiatric entity. His views on SAD and its treatments are best summarized in his book “Winter Blues” first published in 1994.

Some of the far-latitude countries seem relatively spared from SAD, namely in Iceland, Japan and native Alaskans. One thing that distinguishes these countries is the very high intake of fish per capita and fish oils and Vitamin D are said to play a part in this lower incidence of the disorder in those areas. There may also be genetic susceptibility differences.

Paradoxically some people report SAD symptoms in the summer, or in spring, and a full explanation of this is still wanting. Some SAD patients are variants of or have concomitant Bipolar Disorder which is not usually so seasonally affected. In fact the Diagnostic and Statistical Manual of Mental Disorders (DSM) no longer classifies SAD as a separate entity but rather as a ‘specificier’ such as Bipolar Disorder or Recurrent Major Depression ‘with a seasonal pattern’.

The DSM’s list of typical signs and symptoms include difficulty waking in the morning, nausea, tendency to oversleep, tendency to over-eat (especially carbohydrates), weight gain, lack of energy, easy fatigue, loss of interest and pleasure in things that normally give interest and pleasure (so-called anhedonia), difficulty concentrating and in completing tasks, social withdrawal and loss of libido.

Summer and spring sufferers seem to have more insomnia, anxiety, irritability, decreased appetite and weight loss along with social withdrawal and loss of libido.

To qualify as having a ‘seasonal pattern’, the episodes of depression must of course happen at a characteristic time each year with no or few non-seasonal episodes and this pattern must have continued for at least 2 years.

The exact brain chemical changes that underlie SAD are still unclear, but considerableprogress has been made in this area in recent times. In Major Depression the neurotransmitter chemicals serotonin, melatonin and others have been closely implicated with depressive mood and with the success of currently available treatments. Serotonin reuptake inhibitors or blockers (SSRIs) are the current medication mainstay of depression treatment. Newer melatonin type drugs have also recently been introduced into the management of depression, although the jury is still out as to their efficacy in Major Depression.

These neurotransmitters also have a role in regulating the ‘normal’ sleep-wake cycle and/or play a role in the control of appetite and sexual function. Our circadian and other bio-rhythms are set by millions of years evolving on rotating off-axis planet in an elliptical solar orbit with strong cyclical lunar gravity, have this has lead to many synchronies. When those synchronies are lost, or disrupted, so is our mental or physical health.

In our own large series of Depressed patients who had multiple serial blood tests overnight 1, we found that most patients with Major Depression have dysregulated circadian (24-hour) cycles in the blood hormone cortisol, as well as abnormalities in the secretion of brain peptides such as ACTH and Beta-endorphin. The more dysregulated the more depressed as a general rule. But in particular, the more dysregulated the individual’s hormonal and brain peptide diurnal patterns, the more they suffered from slowing in mental and physical activities (so-called ‘psychomotor retardation’).

This circadian abnormality could be tested with more precision by following the specific path of response of these hormones and brain peptides following the oral

1 O’Sullivan BTThe Pharmacokinetics of Dexamethasone and the Dexamethasone Suppression Test in Depression.PhD Thesis (1991) University of Sydney

administration of a synthetic corticosteroid, dexamethasone. Many previous studies using the dexamethasone suppression test (DST) failed to control for wide inter-individual variations in the absorption and blood bio-availability of dexamethasone, rendering their results uninterpretable. But when we did do this, we found that psychomotor retardation was most strongly associated with disrupted circadian hormone patterns.

Clinical experience over many years also tells us that once the sleep cycle gets back insynchrony after antidepressants have been commenced, then clinical recovery from the depressed mood is not far away.

Girls born blind often do not have their first period (menarche) until their late teens. The ‘body clock’ for this seems to be mediated by years of light passing from the eyesinto ancient brain structures such as the pineal gland, a reptilian light-sensitive vestigeand sometimes called a ‘third eye’. Melatonin is normally produced by the pineal in dim light and it therefore signals that it’s time to sleep. It has its own diurnal (circadian) cycle of secretion too. People often consume melatonin orally in the hope that it will bring sleep. and/or avoid the worst effects of jet-lag where normal circadian rhythms are also temporarily disrupted.

As stated above, melatonin and melatonin-like drugs are currently being promoted as additional therapy in Major Depression. Whilst dim light causes a natural secretion of melatonin from the pineal, bright light suppresses the release of melatonin from the pineal, assisting with normal sleep-wake cycles. Other factors such as exercise may also have a key role in regulating serotonin, melatonin and other brain chemicals. The positive effect of exercise upon mood, especially with sunshine, is well known amongst most chronic depressives. It also appears to be the case in SAD as well.

As a personal reflection, I spent 2 years with my young family in Stockholm Sweden as a guest post- MD PhD researcher working on functional human brain imaging techniques. Arriving in summer and naively Australian, we lived with other Australian and other researchers from all over the world at a wide low-level semi-circular apartment building, the Wenner Gren Centre, a philanthropic legacy of Ms Wenner Gren of Electrolux fame and wealth which he bequeathed in order to support overseas researchers in coming to work in Sweden.

It was an honour and a privilege to share our lives with so many highly intelligent andculturally diverse people. But there were some unanticipated negative consequences. We all fell victim to every new cold and flu going around as we had not had previous exposure to many of these local forms. In summer we had to put black cardboard and tape up the bedroom windows in the children’s bedrooms (otherwise they would be out playing in the light well after 10PM). In the winter we all slowed down. It was extremely hard to get moving each morning and 3 out of my 4 children had to get off to an English-speaking school in total darkness. The sun only sat on the horizon between 10AM and 2PM. Many of the locals ‘melted’ into the dark. My supervising Professor would work in winter under a dim pool of light from his desk lamp. Candleswere lit in windows of the apartments (very pretty) and home activities and home ‘crafts’ became popular in the winter months.

But then I noticed. Some apartments had very bright lights left burning for much of the time. It was the other Australian family! There were also two other families from Chile and Argentina. We soon also had our 150 watt globes installed as well and the difference was amazing. The lights created an artificial ‘dawn’ and the lift in our moods and activity was obvious.

Walking to the Karolinska University you pass the Karolinska Hospital. In summer walking from home around the lake took me about 25 minutes, but, in winter, with thelake frozen rock hard, I could walk directly over it and it took just 15 minutes to get towork. Passing the Hospital there was a special room full of people in a bright lit room (a high lux room) who were all chatting and reading magazines. These were the people with SAD.

At first I was bemused, but this was a daily event for many and, along with the social chatter, the SSRI medications, melatonin and other social supports, they did quite well. I also noticed a machine there to create negatively ionized air, but I’m not sure how useful this was. All of the other elements above either singly or in combination were clearly useful to many of these patients.

More definitive studies of SAD in 1995 and 2010 have clearly demonstrated the valueof light therapy. There is some minor controversy about the optimal wavelength, time of exposure etc, but there can be no doubt about its clinical utility in some cases of SAD.

Many people but their own ‘light box’ for use at home and also try to increase their physical exercise.

Although my own family did not have full-blown SAD, it was clear that we were ‘sub-syndromal’. We felt a fraction of the effects, and it was not pleasant. We had also devised or stumbled upon our own methods in summer and in winter to regularize our day-night sleep-wake circadian rhythms. Of Irish extraction, I later found out that the incidence of SAD is probably at its highest in the Irish Celtic stock - about 20% of that population!

Perhaps an associated phenomenon is the high susceptibility I personally experience to jet-lag and its associated disrupted sleep and dysphoric mood. This is quite marked going eastward (effectively speeding up the earth’s rotation relative to my own bio-rhythms), and it is almost completely absent when travelling west!

Such mood susceptibility may be an indicator of life-long susceptibility to depression.Some 20% of the entire population of the World will at some time in their lives suffer from Major Depression. It’s often said that the ‘other 80%’ (and sadly many doctors and Psychiatrists are included in this group) do not and can not understand the true pain, disability and stigma of this otherwise treatable biological condition. Major Depression is well beyond the ‘blues’, ‘winter blues’ or otherwise.