Seasonal Affective Disorder (SAD)

About Light and Depression
Scott Sulak
Change For Good, ® Inc.


As we get closer and closer to the fall and ultimately to winter, many become SAD. That is, many may develop Seasonal Affective Disorder (SAD). Not everyone falls into the same pattern in the winter, however, for those who do, winter can be a very difficult time. Gray skies, rain and cold weather can trigger a number of neurological responses that can make this time of year unbearable.

SAD Symptoms

Symptoms of SAD are sadness, anxiety, irritability and violence. Even if they are not severe enough to warrant hospitalization, the symptoms can still be severe enough to disturb how you function and perhaps even interfere with your personal relationships. Mood certainly changes. Some people become sadder, to the point of experiencing real grief at times. Others become more anxious, and yet others become more irritable. At times the irritability can be so extreme that feelings of violence can erupt. This perhaps is one small part of the reason why the incidence of child abuse seems to increase during the dark months.

Other Symptoms

Physical activity decreases. The person feels very sedentary and often sluggish. Physical activity, sometimes of almost any sort, seems to be just too much. On the other hand, appetite, and especially craving for carbohydrates (sugars, starches or alcohol) actually increases. Hypersomnia can develop. Most people with SAD end up sleeping for very long hours, or wish they could, if life would allow it. In many ways, other than for the sometimes severe emotional symptoms, it is as if a person were hibernating during the cold, dark months.

What Causes SAD

Some have given the name “the holiday blues” to what we now call SAD, or winter depression. The name comes from the fact that problems begin in anticipation of or during the time when the media tells you that you’re supposed to feel warmth and love, and to be in the company of dear friends and family around a cozy hearth, with Nat King Cole in the background and roasted chestnuts on an open fire, exchanging gifts and caring. It follows, then, that depression can be the result among those who cannot be with family or who perhaps live far from friends who they might share the holidays with. According to this way of thinking, the depression comes from a deep sadness, from a heightened awareness of not having such a lovely, and perhaps mythical, place to go for the holidays.

How Scientists Discovered That Light is the Key to SAD

But can it be that we become more vulnerable to feelings of aloneness and other sad thoughts because of the decreasing hours of daylight, and that it is the shorter day’s length which sets the stage for depression? Very probably so, think the scientists. In a now classical research paper authored by Norman Rosenthal and his colleagues, then at the National Institute of Mental Health (NIMH), SAD found its first description and received its name, and preliminary findings regarding a form of treatment with light was documented.

These investigators found that they could predict how many of the people they studied would develop SAD symptoms on the basis of how brief the daylight hours were. As daylight began noticeably decreasing in September, some people were affected. By the time the days of winter solstice came, almost everyone in the study group was affected. Then, as the season moved away from the solstice toward spring with lengthening daylight hours, the number of affected people began to decline. By the end of May, almost everyone was back to his or her old selves, some unfortunately even switching into what psychiatrists call mania.

To make sure that this association between change in mood and amount of light was more than just mere coincidence, the next step was to supply light to see if it could reverse the SAD mood. They used two different kinds of light, just to make sure the extra attention paid to the SAD patients wasn’t what helped resolve the depression. The dimmer, yellow light they used had no effect. However, the brighter light with a frequency spectrum more or less simulating the frequencies in sunlight, produced a marked change in mood in most, but not all, the patients who received that treatment. Their mood lightened, as it were, with the administration of light.

Since then, there has been quite an accumulation of evidence that it is indeed the decreasing length of the photoperiod – the duration of the light part of a 24-hour period – which produces SAD in affected individuals.

The Master Biological Clock

Here is our current understanding. We are biological creatures and, in general, the human race depends a great deal upon being able to see. When primates and then humanity were evolving, before electricity was discovered, of course, but also before the discovery of fire, we could not see well when it was dark out. What better time, then, to sleep, to find a safe place to hole up in and get rest so one’s batteries could be recharged by sun-up for the next day’s hunting and gathering. And so it became necessary to synchronize our internal biological clocks to the light-dark cycle in the geophysical world so that we’d be alert by daylight and become sleepy as the sun began to set.

In recent years, a small cluster of brain cells (i.e., neurons), dubbed the suprachiasmatic nucleus (SCN), has been identified as the master biological clock’s probable site. Not surprisingly, in retrospect, one kind of information the SCN receives has to do with the amount of light coming in through the eyes. In fact, its name simply means that it lies above (supra-) the optic chiasm (chiasmatic), the place in the brain where tracts of fibers originating at the retina of the left eye cross over fiber tracts originating from the right retina. That is, the master clock lies right above an important part of the visual system! With this visual information, the SCN is in a position to coordinate the rhythms of our inner world with the rhythm of the light-dark cycle in the outer world.

Where does the SCN send the information it receives about the amount of light or darkness? Following a complicated pathway which involves a part of the nervous system called the Sympathetic Nervous System, the SCN eventually sends that information to a small gland at the base of the brain called the pineal gland. And it is melatonin, a hormone, that is produced by this gland. The amount of light seems to determine how much pineal melatonin is actually released from the pineal and secreted into the blood stream. The more light, the more release is suppressed. The less light, the more melatonin the blood carries. Light suppresses melatonin release. Research is still being conducted on the effects of using melatonin as a cure for SAD since it will produce sleepiness which is not the desired effect.

Tips for Avoiding the Winter Blahs, Blues, or SAD

· Pay attention to your moods and energy levels. If you realize that your spirits begin to sink at the end of the summer, take pre-emptive action. A good offense is better than an after-the-fact defense.
· Plan active events for yourself in advance of the fall.

· Expose yourself to as much bright light as you can. If it is a sunny day, go outside as much as you can. If it is grey and overcast, use as much light indoors as you can.
· Stay physically active, and begin your physical activity before the blahs get you.
· Try to establish a mental set that will help you to enjoy the wintertime. It is going to happen, so gear yourself to get pleasure out of it.
· By all means, if you feel yourself sinking and realize you are losing control, don’t feel ashamed or try to hide it. You are in good company. Many people feel this way. Seek competent professional help. What you learn for this season is something you can probably do for yourself in all the fall and winter seasons to come.
· Use self-hypnosis or guided imagery to bring yourself into a sunny climate.

Bright Light Therapy (BLT)

· BLT is the most established treatment for SAD.
· BLT consists of looking at special broad spectrum bright lights from one-half to three hours a day, generally in the early morning hours. One should not stare directly into the lights because of possible eye damage.
· A substantial amount of light is needed, which means the distance from the lights to your eyes needs to be monitored – close enough to give you the best amount of light, but distant enough so you don’t hurt your eyes.

· The timing and length of the exposure per day are highly individual.
· BLT is unlikely to help in certain situations because depressed mood is not always related to the decreasing number of daylight hours. Other possibilities are that you may have an ongoing depression, unlikely to be helped by BLT. Your increasing irritability may be due to your spending more hours in the house cooped up, isolated from friends and neighbors. Or it might be due to keeping your dogs or cats in the house more than you do in the summertime and spring. If you are allergic to cats and dogs, doing this will produce allergy symptoms, which can produce poor sleep, which in turn can produce the impression of SAD, but such a mood change then will definitely not respond to BLT. There are many other sources of depressed mood that are unrelated to light exposure.
· If a few days of a light trial don’t make a difference in your depression, seek a different kind of help, perhaps counseling or therapy. There may be some other underlying issue that is bothering you

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