[jkxyz]

Don't forget seasonal affective disorder, or just the general influence on affects that cloudy weather has. Imagine waking up to streaming sunlight every morning. I can see that making a huge change in people's lives.

[seivan]

It would have to produce vitamin-D (or whatever the sunlight produces when it hits your skin) in order to combat that.

Source: Me in wintertime Sweden.

[sneak]

Concurrent orally-administered vitamin D would achieve the same effect.

[erkkie]

Melatonin as well