A reader asks:

 This may sound strange: Is there an opposite disorder to SAD where sunlight actually depresses you? I’ve struggled with sunlight for about 10 years, but have had no skin reaction, other than a melanoma a couple of years ago. I really have a hard time getting through sunny days in a normal manner. It is amazing how wonderful my days are when it is overcast outside.

Answer:

This is an unusual report, but there are some possible explanations. Some people experience “photophobia”–with very disruptive reactions to bright light exposure, which may be related to hypersensitivity of the retina of the eye, psychological factors, or both. If you use a photosensitizing medication, that may be responsible. There have been scattered reports of people becoming very sleepy during and after bright light exposure; it is not clear whether this is due to the time of day of light exposure. Possibly, your reaction to outdoor sunlight is triggered by the strong blue component of white light. If so, you may benefit by using blue-blocking wrap-around glasses, such as Model 58 from noirmedical.com. Finally, you may be suffering from summer depression, which is more plausibly related to high heat and humidity than bright light.