Saturday, September 29, 2007
Shining New Light on Addiction
SAD phototherapy may help with alcoholism
It’s that time of the year again.
For many people, autumn is a bracing and enjoyable time of the year. But for an unlucky minority of people, the advent of seasonal affective disorder, or SAD, is only, and literally, a matter of time. Since the autumnal equinox at 9.51 a.m. GMT on September 23, when daytime lost its annual circadian struggle with nighttime, the amount of daily sunlight slowly but surely diminishes by as much as several minutes a day. And for a few months, it will only get worse. For dwellers in the northern latitudes, the long dark has begun.
To be precise, seasonal affective disorder is not typically considered to be a separate or unique disorder, but rather a symptom of unipolar or general depression, the “garden-variety” form of depression. Both general depression and its seasonal variant involve symptoms such as lethargy, weight gain, carbohydrate craving, oversleeping and joylessness.
The addition of strong light in certain frequencies—a form of phototherapy—helps some people combat this seasonal form of depression. The so-called SAD lights have become a fixture in homes, offices, and mail-order catalogs. The evidence for effectiveness is somewhat controversial, but generally accepted.
Recently, Science magazine has spotlighted work being done on other conditions that may respond to SAD phototherapy. Citing the work of Alfred Lewy and Thomas Wehr at the National Institute of Mental Health (NIMH), who showed that phototherapy worked by decreasing the production of melatonin through a complicated set of reactions leading to an increase in blood levels of serotonin, the article summarizes the evidence showing that many people suffering from either seasonal depression or general depression benefited from spending 30 minutes each morning sitting three feet away from bright white fluorescent lighting--light banks very much like the indoor “grow lights” people often purchase for their house plants.
However unorthodox it may sound, recent studies strongly suggest that phototherapy might also aid people suffering from bipolar disorder, commonly called “manic-depression.” This is a striking possibility, since bipolar depression is distinct from general depression, and rarely responds to the same therapies and medications used for that condition.
This development has led researchers to wonder whether other mental or behavioral disorders partially mediated by fluctuations in serotonin might also respond to light therapy. Last year, writing in the American Family Physician, Stephen J. Lurie and coworkers pointed out that “SAD is associated with serotonergic dysregulation and… may overlap with other diagnoses that share similar mechanisms.”
One diagnosis that shares similar mechanisms is alcoholism. The neurological connection between alcoholism and major depression is well documented by now, and involves serotonin, among other neurotransmitters and neurotransporters that ferry molecules around the brain and the rest of the central nervous system. Brain imaging studies of alcoholics do indeed show a marked reduction in serotonin transporter availability in cases of accompanying depression.
According to Lurie, a summary of recent research findings reveals that “some patients with alcoholism may be self-medicating an underlying depression with alcohol or manifesting a seasonal pattern to alcohol-induced depression.” Such patterns also show genetic underpinnings—SAD often runs in families with a strong history of alcoholism and general depression. All of this, the paper states, “may be related to serotonergic functioning.”
Dr. Leo Sher of the Department of Psychiatry at Columbia University believes that “Family and molecular genetic studies suggest that there may be a genetic link between seasonality and alcoholism.” In an article for the January 2004 issue of Comprehensive Psychiatry, Sher writes:
“The fact that SAD and alcoholism may be comorbid [occur together] shows the importance of a thorough diagnostic interview. Both mental health and drug and alcohol professionals should be provided with education to assist with appropriate identification, management and referral of patients presenting with comorbid alcoholism and SAD.”
For alcoholics who also suffer from seasonal affective disorder, a therapy regimen that includes exposure to bright lights in the morning could do more than boost their moods. It might also help them drink less. Much more research is needed, but the possibility that SAD phototherapy might help curb alcohol cravings or prevent relapse is a hypothesis worthy of further investigation.
Bhattacharjee, Yudhijit, “Is Internal Timing Key to Mental Health?” Science, 317 14 September 2007. (Subscription).
“Alcohol and Seasonal Affective Disorder.” Comprehensive Psychiatry.
“Serotonergic dysfunction, negative mood states, and response to alcohol.” Alcoholism, Clinical and Experimental Research.
"Circadian Phase Variation in Bipolar I Disorder." Chronobiology International
"Influence of a functional polymorphism within the promoter of the serotonin transporter gene on the effects of total sleep deprivation in bipolar depression." Journal of Clinical Psychiatry.
“Seasonal Affective Disorder.” American Family Physician
“Shedding Some Light on Bipolar Disorder.” Living the Scientific Life (Scientist, Interrupted).