A reader asks:

What is the impact of SAD on hormone levels, especially estrogens, prolactin, testosterone and luteinizing hormone? Is it possible that SAD reduces their levels? Could the combination of light therapy and hormones be a more effective treatment than combination with antidepressants?


The effect of SAD on hormone levels is not clear and would benefit from further study. We know of no studies examining SAD effects on estrogens or testosterone. At least two studies suggest that people with SAD do have low prolactin, but another does not. The combination of light therapy with hormones is an intriguing idea, but has never been tested for safety or efficacy.