[freyr]

Interestingly, neither the current linked article nor the original article referenced Vitamin D or even the benefits of sunlight.

The original article linked to a scientific study in which nocturnal animals (rats) were exposed to light over long time periods, which caused the rats to get stressed and depressed.

Apparently, the article's author concluded from this that diurnal animals like humans must get stressed and depressed by long periods of darkness. Probably true, but certainly not supported by the cited study. And it had nothing to do specifically with sunlight, per se.