I WISH I had found Paleo in college. I was in the same boat as you man! My family history includes Manic Depression, or Bi-Polar if you're PC, and I definitely have tendencies. I struggled with it for a long long time, dropped out of college after failing miserably, drinking way too much, doing lots and lots of drugs, blasting through a chunk of inheritance money insanely (ha, pun intended I guess) fast.
Making a long story short, I continued to struggle with self-esteem issues, depression, bouts of mania and insane (there it is again) and irresponsible money-spending until very recently, I'd say about a year and a half or 2 years ago.
I cut back on my drinking, started correcting my late late late night owl sleep patterns with Melatonin, started supplementing with high doses of fish oil "for my brain," I quit smoking, quit all drugs and began eating what I thought was a healthy diet. I got a little better. I now have a wonderful girlfriend, I'm not desperately alone and despairing of life all the time. But I wasn't motivated to DO anything! I know how you feel.
Then I started going to the gym. I had read that exercise can balance moods. It helped a little bit too. Because of the gym I started to read about IF, minimal running and better diets. I found Paleo and never looked back.
Maybe if I'd started with Paleo, I would've noticed a revolutionary change, but on top of everything else, I still do notice that my motivation has gone through the roof. It's an uphill battle, and no ONE thing is the answer. It sure helps to be healthy though!
So far I haven't had any bouts of depression, or extremely manic behavior (although my spending habits will probably never be healthy...I don't have a credit card though, thank the gods!) and I feel great.