Natural treatments for seasonal and non-seasonal depression: a review of literature and comparison of antidepressant responses

Abstract

The symptoms of depression might be alleviated by such non-pharmacological interventions as sleep deprivation, bright light exposure, and physical exercise. Some strategies of non-drug treatment for seasonal and non-seasonal depression seem to be very effective, but the involvement of specific biological mechanisms in the observed beneficial response still remains to be clarified. A present literature review was combined with a brief summary of the results of a set of author’s investigations that provided a possibility to compare the antidepressant effects of several one-week treatments in 268 female subjects with either winter depression or non-seasonal depression or without depression (n=118, 64 and 86, respectively). It was demonstrated that a total night sleep deprivation failed to improve mood in non-depressed subjects, whereas in seasonally and non-seasonally depressed subjects the significant improvements of similar magnitudes were observed. Furthermore, any type of one-week treatment (i.e., 6 or 7 days of bright light, physical exercise, melatonin or placebo intake, and vocation in a south region) administered either alone or in combination with one night of sleep deprivation produced a notable reduction of depression scores in both depressed and non-depressed subjects. Such treatments prevented relapse after sleep deprivation. Mood further improved after visual treatments, such as bright light and physical exercise, rather than after blind intake of ether melatonin or placebo. The studies of natural antidepressants highlighted the possibility that they often work as powerful placebos, and that, compared to the biology of depressives; their psychology is the most important mediator of clinical response. Further research might be aimed on testing the predictions based on evolutionary explanation of depression and antidepressant responses to natural treatments.