I’ve found a new way of dealing with seasonal affective disorder: by shooting high-key winter scenes.
Not only does it force me to get outside for my 15 minutes of sunshine (or clouds), seeing the snow and background as white instead of the more realistic gray really helps my mood.
A year ago, I actively avoided overexposing shots that included snow. I worried about all of the photographic information that was lost if I didn’t have detail on every snowflake. Now I say: bah! who needs all those (extra) shades of gray?
If you’re not purposefully controlling shutter speed, just go with a relatively wide aperture (low f-stop); and, using aperture priority mode, overexpose by a stop or two (or more).
Save money! Replace your light therapy with some happy, overexposed photos!