Which vitamin supplements are actually useful?

So I’ve got really bad anxiety, seasonal affective disorder, chronic fatigue, and a bunch of other issues I’ve been dealing with for a log time. In a bid to help me out, my housemate has put me on a regimen of vitamin supplements. I’ve been on Wikipedia reading about various vitamins and it seems like every article is nothing but “vitamin whatever doesn’t actually do anything/there’s no evidence that vitamin take-your-pick actually helps with ailment whatever/vitamin whatchamacallit is actually toxic…” and so on. So my question is: are any vitamin supplements actually worth taking according to science? Or is Wikipedia just full of shit?