A review of Defeating SAD: A Guide to Health and Happiness in All Seasons by Norman E. Rosenthal, M.D. / Gildan Media, 2023

Seasonal Affective Disorder (SAD) has logged an impressive history of clinical trials starting in the early 1980s, yet the endeavor still feels novel and challenging.  It was sparked by the revolutionary study of bright light therapy led by Norman E. Rosenthal, M.D., at the Clinical Psychobiology Branch of the U.S. National Institute of Mental Health (NIMH).  Over 3000 scholarly publications have followed, an unprecedented international response attesting to remarkable success in symptom reduction without recourse to medications or psychotherapy.

Controlled trials have aimed optimistically for complete relief from the gloom and dread that may seem to come from nowhere, although seasonal change in natural light availability has provided a strong clue.  Still, even in the cleanest clinical trials, a fair number of patients have remained symptomatic. The most successful light therapy trials have shown virtually complete relief from the winter mood ailment in about half the patients. This is a miraculous result, given the multi-symptom complex of clinical depression. About another 30% showed partial improvement with persistent residual symptoms, yet still much better than at entry. And then, there were the puzzling nonresponders, as if they had received no treatment.

The pattern of positive results served as a lightning rod for public enthusiasm, and an entire industry of light therapy devices bloomed as a counterpoint to traditional medications, encouraging virtually risk-free experimentation for the consumer, often without professional supervision, and attracting them with the promise of a quick fix. Furthermore, many people who felt significant worsening of mood and functioning in the fall and winter had never considered that their depression would be suitable for conventional psychiatric medication or psychotherapy.  Unstructured, home-brewed trials of light therapy seemed risk-free, inexpensive, self-directed, and worth a chance. There has been enough success to maintain public interest — this was not a fad — and the risk of partial response or nonresponse has been accepted.

Rosenthal’s new book takes the bull by the horns, pointing to ways positive response can be enhanced over the boost offered by light therapy. In Defeating SAD, he surveys multiple compatible approaches to treatment with the promise of greatly increased response, whether as supplemental to light therapy or independently. Whether this can inspire a new round of sponsored clinical trials remains to be seen, as priorities for federal research support have shifted, and there is little incentive for the commercial sector. Yet, Rosenthal points to a set of accessible methods whose combination is clearly worth a try.

Most SAD patients should expect some trial and error before finding a fully satisfying therapeutic result. The same is true for all depression, seasonal or not. The book is filled with options and alternatives to light therapy, based both on clinical trials and the experience and solutions of hundreds of Rosenthal’s patients. It is no doubt challenging to try and then evaluate the combination that works for you, but this is time well spent if you can minimize residual symptoms of SAD.

It is important to experiment with these treatments while you’re actively depressed, where psychotherapy can come in. Rosenthal explains cognitive behavioral therapy (CBT), which provides the best chance of reducing depressive symptoms. In this method, you learn to detect and capitalize on positive factors buried under negative feelings that dominate your thinking and needlessly amplify the misery. CBT can also work as a solo therapy without light therapy while promising a milder experience in future winters. Comparatively, light therapy can provide a quicker fix, but it requires continuing each year to maintain the benefit.

The necessity of brighter-than-normal illumination from light boxes has a counterpoint in dim simulations of pre-sunrise dawns in the darkened bedroom. It was a surprise that this could work as effectively as bright light therapy after waking up. Two factors may be responsible: (1) the eyes become more sensitive to light while sleeping in darkness, and (2) our circadian rhythms shift earlier in response to light toward the end of the night, which is one theory of antidepressant action. Some patients have combined dawn simulation with post-awakening bright light for an additional energy boost.

Rosenthal devotes a short chapter to negative air ionization, another physical factor in our environment that has nothing to do with light. Like natural light, however, ion availability in the air circulation fluctuates seasonally, especially if you spend most of your time indoors in a dry, heated home or workplace. Electronic devices further attract and dissipate these therapeutic air particles. You can amplify negative air ion concentration with a small device that covers the room with positive benefits for mood. However, just like 30 minutes of light therapy, the ionizer requires a daily commitment for a similar amount of time.

Rosenthal also dives into considerations of taking antidepressant medications.  Many experienced patients prefer to substitute light therapy or decrease drug dose as the light effect comes in, however, he provides detailed information comparing drug classes that can work for SAD. He cites an important study of three groups of nonseasonal patients who received light therapy, the popular serotoninergic drug fluoxetine, or placebo. Those who received light therapy responded better than those given the drug or placebo. Studies such as this show the promise of light therapy as an alternative or supplement for patients with nonseasonal depression. Adequate light exposure is key to improved mood regardless of seasonality. During a depression, individuals will often minimize exposure even to ordinary room light and spend much less time outdoors, where natural daylight could benefit.

Dietary choices are also key to defeating SAD. Food choices can trigger weight gain and high-low mood fluctuations, and food selection should be a priority for anyone with SAD. Rosenthal points out that the mishandling of carbohydrates is prominent in SAD, and the resulting weight gain can be the most difficult physical symptom to treat. Interestingly, a study of over 100 SAD patients found that increased eating and carbohydrate craving predicted mood improvement to light therapy while weight loss remained slow to respond. Rosenthal offers specific recommendations for satisfying foods that discourage weight gain, which makes dietary choice another therapeutic strategy to support light therapy.

It can be daunting to digest the extensive array of alternate treatments that boost the response to light or act independently. The expanded array of proven therapeutic opportunities is impressive, but taking the next step can be challenging. Family members are best positioned to notice an improvement when it happens or suggest alternatives if the patient stays gloomy. I recommend that family members read this book and discuss the alternatives with the patient. While lucky ones will respond completely to light therapy, combination treatment or alternate strategies deserve serious consideration. Waiting until spontaneous remission in the spring wastes precious time, considering that the patient might be able to resolve the winter episode within a week of concentrated effort.  Family attention and support is often the key to success in defeating SAD. Rosenthal’s book provides a comprehensive guide to the road to that defeat —  it is a must-read for anyone suffering.

Michael Terman, PhD / Center for Environmental Therapeutics

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