A Yale investigator and his Israeli colleagues have shown for the first time that the body has light receptors other than those in the eye’s visual system. That finding may help explain why using artificial light as therapy helps people with seasonal affective disorder (SAD), a form of depression believed to result from light deprivation, occurring most commonly during winter. It could also help lead to the development of light therapies for other forms of depression, according to the paper’s senior author, Associate Professor of Psychiatry Dan A. Oren, M.D.
For the study, which appeared in the March 1 issue of the journal Biological Psychiatry, light from a type of light box commonly used to treat SAD was directed on skin cells grown in culture. Within 10 minutes, the light stimulated production of molecules containing so-called free radicals, which are gases that can deliver energy through the bloodstream. This may help explain why light can help treat SAD, which affects as many as 20 million Americans, and provides, said Oren, “a new pathway toward understanding how the brain works.”
Oren is also principal investigator for a study using light to treat pregnant women suffering from depression. Oren and C. Neill Epperson, M.D., assistant professor of psychiatry and of obstetrics and gynecology, are testing women to see whether light therapy will allow them to avoid antidepressant medications, because of concerns about the drugs’ potential side effects and/or toxic effects on the fetus. According to Oren, an open-treatment trial had “very encouraging” results. Yale and two other research centers are now pursuing a pilot study in hopes of undertaking a larger-scale investigation.