Behavior modification via dopamine?

Dopamine is a neurotransmitter that affects mood, generally producing feelings of pleasure or contentment. One effect of it is that behaviors that cause elevated dopamine levels tend to become habit-forming. Can we use this to our advantage by “self-medicating” with dopamine in order to help ourselves acquire healthy (or otherwise beneficial) habits?

For example, if I usually hate exercise (or am just too lazy to do it), could I pop a dopamine pill whenever I go to the gym, so that eventually exercising is associated with positive feelings, and becomes something that I make an effort to do, instead of avoiding it? Or, if I’m not a morning person and want to become one, could I pop a dopamine as soon as the alarm goes off so that I associate early mornings with positive emotions?

Two objections come to mind:

  1. Dopamine could turn the desired behavior into an addiction – you’d want to spend too much time at the gym, which would negate the positive benefit. Perhaps this could be avoided by careful attention to the dosage of dopamine?

  2. Most supplements claiming to boost dopamine levels are actually for dopamine precursors (like tyrosine), and not dopamine itself. My guess is that perhaps this is because dopamine itself won’t cross the blood-brain barrier, and so must be synthesized directly within the brain. Or perhaps dopamine can’t survive the conditions of the GI tract and would break down before the body absorbed it. Anyway, dopamine itself doesn’t seem to be available OTC, and I suspect the precursors you can buy don’t have a rapid enough effect to allow your brain to establish a connection between the dopamine rush and the positive behavior you wanted to reinforce when you took the pill.

Can any neuroscience dopers weigh in?