While doing research for my cat, looking for help with kidney damage to prevent her from going into kidney failure, I ran across & an article that said that it is recommended for help in the kidneys. It is done with a heat lamp &/or a stick, but, I don't recall @ the moment, what it is called.
Lack of sunlight, I know, can make depression worse & sometimes make you more susceptible to it.
Who are you asking about it for? A person or animal?
I personally think it is worth checking into & it is something that you can do at home. No need for visits to a Dr. or vet, no insurance involved. Just a comfortable place to be, the bulb, a clamp lamp & some electricity! (If I can find those articles back, I will give you the links to the sites.
But, yes, I think it would be worth it!