Which variant matches best?
  1. Life is great when the drugs/meds fit.
  2. Life's great. Especially so, if the antidepressant you're taking doesn't give you headaches.
  3. Life's great unless Prozac gives you headaches.
  4. Life is good/wonderful/beautiful if you're on the right meds.
  5. Proper tranquillizers will make you happy
  6. One's happiness depends on proper tranquillizers/antidepressants.

Personally, I vote for numbers 3 & 4


upd: more variants from LJ:
  • Life is beautiful, if you know what prozac is.
  • Life is beautiful, if the pills are right
  • Life's great as you get the right pills