I'd counter that an addict may need more of a few things than the average healthy adult. Perhaps a little extra magnesium for the calming effects, stuff like that. Drug use wreaks havoc on your brain chemistry and there are a few vitamins/minerals/supplements that can support your system when it's under stress. I'd call this harm reduction. ☺ To the OP, if you're going heavy on carbs to gain weight, do brown/wild rice or sprouted grain bread rather than their white counterparts. You need all the vitamins and trace minerals you can get. I'd also recommend protein shakes. Really easy to get down when your appetite isn't there. As far as the basic diet part, lean protein, a variety of fruits/veg, and whole grains, along with healthy fats like olive oil, nuts, and avocado. And if you do one supplement, I'd recommend high quality omegas by a brand like nordic naturals. It functions as an anti-inflammatory and has been shown to help with depression, among many other things. The good quality supplements are pretty much only at health food stores. Good luck. ☺
If a mod finds a better place for this thread please move it but I think it's a valid question