Neuroleptic drugs are used in psychiatry for their antipsychotic actions. The current pharmacological hypothesis for their mechanism of action is largely based on the correlation between their potency to block dopamine (DA) receptors with their antipsychotic actions. Recently, the effect of chronic neuroleptic treatment on the concentrations of three neuropeptides, methionine-enkephalin (Met-ENK), cholecystokinin octapeptide (CCK-8) and neurotensin (NT), has been studied. These data are reviewed and evaluated in light of the possibility that neuroleptic drug action may be mediated, in part, through alterations in neuropeptide systems
