Cocaine, as we shall see, exerts its euphoric effect by increasing the availability of the reward chemical dopamine in key brain circuits, and this is necessary for motivation and for mental and physical energy. Flooded with artificially high levels of dopamine triggered by external substances, the brain’s own mechanisms of dopamine secretion become lazy. They stop functioning at anywhere near full capacity, relying on the artificial boosters instead. Only long months of abstinence allow the intrinsic machinery of dopamine production to regenerate, and in the meantime, the addict will
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