An Analysis on Seasonal Affective Disorder and the effects of Climate and Lighting on Emotion
Brain, Mind & Behavior

"Seasonal affective disorder also known as winter depression, winter blues, summer depression, summer blues, or seasonal depression, is a mood disorder in which people who have normal health throughout most of the year experience depressive symptoms in the winter or summer, spring or autumn year after year." In the DSM-IV, it is not characterized as a unique mood disorder but considered a 'specifier of major depression'. (Stephen, 2007) Is it not more than a convenience that the year’s most joyous holidays occur on the onset of the winter solstice? The impact of light on emotion has been shown and linked by numerous surveys and tests in the past. Low or dark lighting has been shown to cause eye fatigue and headaches. Absence of natural daylight triggers depression and poor immune defenses. Insufficient lighting is linked to emotional stress and to physical ailments. Bright light stimulates emotions, while low levels of illumination quiet the senses. On the other hand, an excess of unnatural light does not replace the calming effects of natural daylight. Too much artificial light and overly-bright rooms hurt the eyes and make one feel jittery. (Fisher E. , 2004) The impact of lighting on mood and cognition has been difficult to demonstrate because people in industrialized countries, on average, spend 93 percent of their time indoors, making them largely disconnected from the impact of outside light. Many people can just turn on artificial lighting to get the same general effect of daylight. Most people feel an increased sense of sadness in the winter, with the most extreme example being among those who suffer from Seasonal Affective Disorder (SAD), a recurrent depression with typical onset during the fall or winter. (Stephen, 2007) Researchers at the University of Michigan concluded that the optimal type of light is natural daylight, and that it invokes an upbeat emotion in most people. (Lam, 2006) It is evident that the lack of light and change in climate, primarily throughout the winter solstice, has a direct effect on one’s disposition. Twenty percent of U.S. citizens are affected by seasonality, or change in season. Over 10 million Americans suffer Seasonal Affective Disorder and another 14% of citizen’s deal with a common lesser form of SAD, known as the Winter Blue’s, granted they are affected during the fall or winter. In total, seasonality causes about 20% of the entire U.S. population to suffer distress, mood changes, fatigue and sometimes even depression throughout the winter months. (Rosenthal, 1998) Often, people suffering from SAD experience depression during the onset of fall or winter suffer from physiological changes including lack of energy, decreased interest in work or significant activities, increased appetite with apparent weight gain – including a craving for carbohydrates, increased sleeping hours with more daily naps, social withdrawal, and sluggish movement. (Stephen, 2007) Although one can be subjected to SAD geographically anywhere, it is more common in certain places, typically in areas where the winter days are very short, having smaller duration of daylight or places where the amount of sunlight drastically changes with each season. New Hampshire and Alaska are prime examples of this. Regions near the equator do not appear to have as many SAD sufferers because of their geographic location, which receives the most sunlight compared to any other regions, especially the far north, from New England to Canada and above and deep south within Antarctica, which receives the least amount of sunlight on Earth. (Rosenthal, 1998) Many identify Seasonal Affective Disorder with the hibernation of a bear because of the constant dreary state one suffers with SAD. Although it is not scientifically accepted, it could provide a theory into why SAD occurs. When imagining a bear during its hibernation stage, it is natural to connect it with an SAD patient and its common antisocial and fatigued demeanor. One could question whether perhaps SAD is a natural adaptive state useful for conserving energy for humans analogous to hibernation for bears. Perhaps SAD is a purposeful condition that the body undergoes for unclear benefits, which explains why there are a vast amount of winter blues cases. This theory leads Dr. Norman E. Rosenthal to question, “Is it not our society rather than our biology that is at fault for expecting us to function fully all year round in a manner that is contrary to the ways of nature?” (Rosenthal, 1998) Psychiatrist Dr. Alfred J. Lewy has another pragmatic theory on the occurrence of Seasonal Affective Disorder. Lewy’s concept proposes that SAD is a form of jet lag. Recently published, was his evidence validating his theory that SAD implements the same effect on your body as if one was to travel through several time zones. Jet lag affects the circadian rhythm of the body. The circadian rhythm is the 24-hour pattern that normally aligns the sleep-wake cycle with all the other bodily rhythms. (Brody, 2008) The delayed dawn and reduced hours of sunlight throws off a SAD patient’s circadian rhythm, causing it to drift out of the normal sleep-wake cycle. Dr. Lewy summarizes this proposed physiological phenomena saying “With jet lag, recovery occurs over a matter of days, and the circadian rhythm once again becomes synchronized with day and night. In people with SAD, this adjustment takes five months.” Melatonin, the substance in the brain that regulates the sleep-wake cycle could be the solution to the problem if Lewy’s theory is to be accurately attested. Small doses could be given to patients in attempt to realign their sleep-wake cycle with all other bodily rhythms. Melatonin is already used to help resolve jet lag in travelers. (Brody, 2008) The general cause of Seasonal Affective Disorder is one’s lack of light from the environment, which is why the majority of SAD cases occur during winter’s dark and gloomy days. With that said, there is an obvious treatment that involves supplying a patient’s biological need for light, known as light therapy. Light therapy helps SAD sufferers regain a cheerful, more energetic state of mind, almost as if they were experiencing summer. (Rosenthal, 1998) Many different procedures of light therapy can be performed including just going outside and taking advantage of those rare sunny winter days. Most commonly, procedures involve using a special light fixture or light box. Other light administrating objects include light visors and dawn simulators. (Lam, 2006) Dawn simulators replicate an actual sunny morning scenario for patients as they wake up in the dark mornings of winter. Like all medical treatments, light therapy has side effects; luckily they are few in number and relatively mild. General side effects include headaches, fatigue and anxiety. (Seasonal Affective Disorder (SAD) - Topic Overview, 2006) These effects decrease over time throughout one’s light therapy treatments. Light therapy is so successful because it aids the pineal gland in producing melatonin, the hormone that regulates the circadian rhythms, as discussed above. Over 2/3 of SAD patients see an exponential decrease in symptoms with consistent light therapy regiments. Severe cases can lead to the prescribed use of anti-depressants to aid in hindering SAD effects when light therapy and other pragmatic treatments do not avail. (Rosenthal, 1998) It seems ironic that the most celebrated and festive days of the year take place during the darkest months. Perhaps even thousands of years ago, humans who suffered from this disorder did what they could to help themselves and based our calendar and events on it. There is no doubt in the existence of Seasonal Affective Disorder. Climate change and lack of light can indeed alter one’s state-of-mind or reduce one’s overall happiness because of its effect on the body’s melatonin levels and the circadian rhythms it regulates, causing Seasonal Affective Disorder. With that said, one should not have to -and has the ability to - reduce or hinder its over-bearing effects. Increased recognition and a plethora of recent beneficial treatments are helping to shine the light on the darkest days of those who suffer from Seasonal Affective Disorder. Personally, I found learning about Seasonal Affective Disorder very intriguing because I found I could relate to a lot of the symptom discussed in class and in the book. While I do not think my symptoms are severe enough to be clinically diagnosed with SAD, I understand on a smaller scale what those who do have the disorder go through. Every winter, as the solstice nears, I find myself getting tired quicker in the day and in turn sleeping more hours every night. And despite the extra hours of sleep I gain, I often lack the feeling of refreshment or a burst of energy in the morning. My body really struggles with waking up when the sun has not risen. I think it breaks down to a biological need humans have for sun light and its indication that it is day time. I strongly agree with Dr. Rosenthal's assertion that perhaps society's makeup and framework puts too much pressure on individuals to perform constantly the same year round when our bodies experience different and uncontrollable environment changes that affect both our physiological and psychological ability to perform.

Works Cited

Brody, J. (2006, 12 5). Getting a Grip on the Winter Blues. Retrieved from New York Times: http://www.nytimes.com/health/05brody.html
Fisher, E. (2004). Lighting and Your Emotions. Retrieved from Ezine Articles: http://ezinearticles.com/?Lighting-and-your-emtions-(part-one)&id
Lam, R., & Levitt, A. (2006). The Can-SAD Study. American Journal of Psychiatry.
Rosenthal, N. E. (1998). Winterblues. New York: The Guilford Press.
Seasonal Affective Disorder (SAD) - Topic Overview. (2006, May). Retrieved from Web MD.
Stephen, K. (2007). Biological Psychology. Worth Publishing Company.