New study may explain cause of "winter blues"
We've all experienced the shift that occurs when the climate kicks from warm to cool, and scientists have isolated one of the possible causes for SAD (seasonal affective disorder):
In the first study of its kind in the living human brain, Dr. Jeffrey Meyer and colleagues at the Centre for Addiction and Mental Health (CAMH) have discovered greater levels of serotonin transporter in the brain in winter than in summer. These findings have important implications for understanding seasonal mood change in healthy people, vulnerability to seasonal affective disorders and the relationship of light exposure to mood.
Serotonin works within the central nervous system to regulate emotional functions such as anger, mood, sexuality and aggression, in addition to physical functions like appetite and energy levels. Serotonin transporter works to clear the brain of this this vital chemical, and when serotonin levels are low people will experience difficulty functioning in the above areas.
As Dr. Meyer explains, this is "an important lead in understanding how season changes serotonin levels. This offers an explanation for why some healthy people experience low mood and energy in the winter, and why there is a regular reoccurrence of depressive episodes in fall and winter in some vulnerable individuals. The next steps will be to understand what causes this change and how to interfere with it."
According to the world health organization, major depressive disorder is the fourth leading cause of death and disability. Dr. Meyer points out that, "the future for treatment should be to prevent the illness itself." The presence of higher serotonin transporter levels might explain why many people experience the onset of major depressive episodes in the fall and winter. "Over the following years, we intend to determine the specifics of the environment (such as light exposure) that influence serotonin transporter levels so as to determine what is the optimal environment to prevent illness. In the future, it may be that just like we have lifestyle recommendations to prevent heart disease, we will have lifestyle recommendations to prevent major depressive disorder."
Dr Jonathan Johnston, a lecturer in neuroscience at the University of Surrey, said: "The data show a correlation between a serotonin transporter chemical and hours of sunshine, although how day-length might change transporter activity is not yet known."
Professor Michael Terman, an expert in seasonal affective disorder at Columbia University in New York, said the causes were likely to be complex. He said the condition might be linked to disturbance caused to the body's natural daily rhythm by the fact that dawn and dusk were closer together in the winter. He said research had shown that symptoms of winter depression had been reduced by brief exposure to light around dawn. This suggests that the timing of exposure to light, rather than the simple volume of exposure might be important.
Looks like getting one of those ridiculous light therapy sun simulator lamps throughout the winter isn't such a bad idea...