The year 2006 brought some major news for the treatment of seasonal affective disorder (SAD), with the culmination of several ambitious multi-year and multi-center clinical trials.
The year for drugs?
Maybe, maybe not. Here’s the scoop:
A Canadian study compared morning bright light therapy with Prozac (fluoxetine hydrochloride) in separate groups of patients. After one week, the bright light group did better, but from then on both groups improved similarly over the next seven weeks. On the plus side, we learned that light--a non-pharmaceutical treatment--did just as well as the drug (and without drug side effects). One the minus side, there was no placebo group, so we don’t know how much patients’ expectations alone produced the improvement (more about this below). Also, light therapy might have shown superiority if it had been dosed according to circadian rhythm principles, i.e., according to each individual’s chronotype rather than at a standard time for everyone (too early for some, too late for others). An earlier study showed that timing the light according to chronotype could double the response rate. You can time your light using the Automated Morningness-Eveningness Questionnaire.
A second drug study published in 2006 cleverly administered bupropion (Wellbutrin XL) to SAD patients while they were still feeling well in the fall, with the idea that once the drug was in the bloodstream they could avoid the entire episode of winter depression. On the plus side, it worked: significantly more patients taking the drug by-passed the depressive episode than those given placebo. On the minus side, about 70 percent of the patients on placebo also by-passed the episode, which tells us that the experience of winter depression is quite susceptible to patients’ expectations of a positive treatment effect. Nagging question: if you are not destined to become depressed in a given winter, is it wise to be taking an antidepressant?
Also not to overlook: the fluoxetine trial does not tell us whether winter depression might also be prevented by taking the drug before winter symptoms set in, and the bupropion trial does not tell us whether a patient suffering from winter depression would improve by starting the drug after the symptoms set in. We would guess that the proactive and retroactive methods would work for both drugs, but this has not yet been directly demonstrated.
Head-to-head comparison of environmental therapies
SAD sufferers are lucky to have a well-tested armamentarium of non-drug therapies--bright light therapy, dawn simulation therapy and high-density negative air ion therapy (click here for overviews). Until now, however, there was no sense of which environmental therapy does the best job. The December 2006 issue of the American Journal of Psychiatry reports my clinical trial of the three methods, including a placebo control, low-density negative air ionization. In a twist on our earlier studies of ionization, we activated the ionizers during sleep rather than in post-awakening treatment sessions. All three methods were statistically superior to placebo, but they were not statistically different from each other. In terms of absolute success rates, bright light therapy upon awakening did slightly better than dawn simulation or high-density negative air ionization during sleep, but the difference may not be reliable. So, how to choose between them? It may boil down to convenience: treatment during sleep saves the time and effort of a treatment session at breakfast. On the other hand, bright light therapy is the most extensively tested method. Not to forget: individual patients may respond to one of these methods more strongly than another, so if one doesn’t work, the others should not be disregarded.
Blue light brouhaha
A major problem in our field has been the lack of FDA safety and efficacy standards, which allows manufacturers to jump in with unverified, exaggerated and even deceptive claims for “treatment devices.” In the past year, we have seen the mass marketing of tiny blue-light devices, with the unverified claim of superiority over well-tested white light devices. Furthermore, the safety question looms, especially for people at risk for age-related macular degeneration. Another manufacturer has developed a compromise product--white light “enriched” (their word) with blue. Research studies thus far indicate no advantage over well-tested broad-spectrum bright light therapy, and these marketing initiatives should be viewed with extreme skepticism, if not alarm.