Inhibitors of Enkephalin Catabolism

Typically, long-term administration of opiates leads to a reduction in the magnitude and duration of effects produced by a given dose (tolerance) and to physical dependence, a state manifested by withdrawal symptoms when drug taking is terminated or significantly reduced. Addiction or psychological dependence implies the compulsive self-administration of the drug, caused by both its reinforcing or rewarding effects and the unpleasant experience (i.e., abstinence syndrome) produced by the sudden interruption of its consumption. In contrast to tolerance or physical dependence, addiction is not simply a biological phenomenon. Psychological, environmental, and social factors can strongly influence its development. All these factors could explain the important variability of the clinical syndrome of addiction, and the various approaches that have been proposed to help addicts to stop their drug use. Nevertheless, these methods do not work equally well for all types of addicts.