Suggest Remedy For Treatment Resistant Depression

My son-- 28 yrs old --has decided to stop taking his antidepressant--Wellbutrin. What will be the negative effect of this decision? His dosage was increased to 300 milligrams -- caused aggression. Reduced to 150 milligrams-- Better but still edgy and somewhat volatile--moody etc. Now he is refusing to take anything. Hi doctor wanted to add Ability -he had been on this but we lost insurance and could not afford it. Are there over the counter supplements? His diagnosis is Treatment resistant depression/bipolar/social anxiety/ADHD.