Stimulant drugs like cocaine and methamphetamine (crystal meth) exert their effect by making more dopamine available to cells that are activated by this brain chemical. Because dopamine is important for motivation, incentive and energy, a diminished number of receptors will reduce the addict’s stamina and his incentive and drive for normal activities when not using the drug. It’s a vicious cycle: more cocaine use leads to more loss of dopamine receptors. The fewer receptors, the more the addict needs to supply his brain with an artificial chemical to make up for the lack.
