Seasonal Affective Disorder & The Body Clock

During the winter holiday season, Patients of SAD at the best addiction treatment center in Karachi felt bombarded with a consistent message from television, radio, and movies: this is a time of celebration and joy, a time to feel good cheer and have high spirits. For those suffering from Seasonal Affective Disorder (SAD), however, winter's shorter, darker days promote quite the opposite state of mind.

What is Seasonal Affective Disorder?

Seasonal Affective Disorder is a type of depressive mood disorder related to seasonal variations in light. First identified around 1845, SAD was officially named in the early 1980s. People want to know What the Best Anxiety Cure is for their better life spending; sunlight affects the seasonal activities of animals – such as reproductive cycles and hibernation – and scientists suggest that SAD may be an effect of seasonal light variation in humans. As seasons change, there is a shift in our internal biological "clock" or circadian rhythm, partly resulting from these changes in sunlight patterns. These shifts can cause our biological clocks to be out of step with our daily schedules and are also linked to depression in some people. SAD is more common in women than men and usually doesn't start in people younger than twenty; the disorder's risk decreases as adults age.

Possible Causes

Melatonin, a sleep-related hormone secreted by the pineal gland in the brain, is produced at higher levels in the dark and has been associated with SAD. During shorter days with fewer hours of light, melatonin production increases and may cause depression. Shifts in the internal biological clock caused by changes in light exposure may also play a role. A link between circadian clock disorders and psychiatric disease has long been suspected. People suffering from major depression, bipolar disorder, and SAD often show substantial abnormalities in their sleep-wake cycles.

Treatment

Because the condition is associated with shorter daylight hours, light therapy is often used to treat SAD. In light therapy, a box outfitted with unique lights is used within about ten minutes of waking up in the morning, as sessions at that time of day have been found to have the most significant impact on adjusting and re-regulating the body's circadian rhythm. In some cases, doctors may also prescribe anti-depressants for treating SAD.

NARSAD Supports SAD and Body-Clock Research

Body-clock research is essential for understanding SAD and also has far reaching implications for other psychiatric disorders. Since the 1980s, NARSAD scientists have been seeking to understand better the role that melatonin and our internal biological clocks play in mental illness, including seasonal and non-seasonal depression.

Among the first NARSAD researchers in the 1980s to examine these issues was Sari Gilman-Aronson, M.D., University of Illinois College of Medicine at Urbana-Champaign (1987 Young Investigator, formerly of the University of Pittsburgh). Dr. Gilman-Aronson's study focused on biological rhythm issues in depression, specifically looking at the body-clock changes in someone suffering from recurrent major depression. She and her colleagues investigated the effects of bright evening light on the sleep and core body temperature of depressed patients. Dr. Gilman-Aronson's NARSAD funded study allowed her to continue her experimental research on bright light and circadian rhythms and laid the groundwork for the researchers that followed her in the field.

A decade later, Robert D. Levitan, M.D., Centre for Addiction and Mental Health, University of Toronto (1998 & 2000 Young Investigator), took the line of inquiry in a novel direction, looking at a genetic variation in the serotonin system as a possible common thread between Bulimia Nervosa (B.N.) and SAD. There is strong evidence that the brain chemical, serotonin, plays an essential role in eating. There is also significant evidence that abnormalities in serotonin play a role in both bulimia and SAD, disorders that are both characterized by increased food intake. Dr. Levitan studied the genetics of the serotonin system in female patients with bulimia or SAD, a study that yielded essential findings for both conditions. In the field of eating disorder research, it has been noted that some people living with bulimia achieve very low body weights (and may develop anorexia nervosa).

In contrast, others have a natural limit to their weight loss. Dr. Levitan's team found a particular gene in the serotonin system that strongly differentiates these two groups of patients, a finding that may have implications far beyond the area of eating disorders. The team's second compelling finding suggests a possible association between variations in the serotonin-2A receptor gene, childhood Attention Deficit Disorder, and the later development of SAD in women. Dr. Levitan continues his important work on the genetics of disordered eating in bulimia nervosa and SAD, with ongoing investigations into the serotonin and dopamine neurotransmitter systems.

D. Alfred Lewy, M.D., Ph.D., Oregon Health Sciences University, (1992 & 2000 Distinguished Investigator), is internationally recognized as a pioneer in the field of human chronobiology (the study of biological rhythms and timing mechanisms, including sleep-wake cycles, heart rate, and body temperature). His first NARSAD study was a 1992 pilot project on melatonin as a possible treatment for the chronobiologic disorder. The resulting data provided important information on optimal dosing and timing of melatonin to help adjust out-of-phase internal clocks. Additionally, this research helped lay the groundwork for his three National Institute of Health (NIH) grants that followed. Dr. Lewy continued research in this area, studying melatonin's effectiveness in resetting the internal clocks in blind people whose inability to perceive light throws off their bodies' phases. The groundbreaking results of this work were widely reported by the media and were published in the October 2000 issue of the New England Journal of Medicine. Dr. Lewy was awarded a second NARSAD grant in 2000 and is studying melatonin as a treatment for non-seasonal depression and bipolar disorder.