ABSTRACT
Sensitization has been demonstrated in the brains of ordinary people, as direct elevation of the amount of mesolimbic dopamine released in response to an addictive drug. Neurochemically, sensitization leads to an enhanced dopamine elevation produced by an addictive drug in the synapses of the nucleus accumbens in the face of a drug challenge. Addictive cravings often wax and wane, a feature that contradicts notions of addiction as a constant unchanging habit. Sensitization is a complex phenomenon that is influenced by the dose, timing, and spacing of the drug, along with the context in which it is taken, and individual features of the person who is taking it. Mechanisms of induction and expression of sensitization may differ across drugs, but sensitization to one drug often will produce a sensitized response to other drugs, an effect otherwise known as cross-sensitization. Gambling might also involve special recruitment of incentive salience brain systems.
