Interaction of neuroleptics with dopamine receptors is generally accepted to be important for their antipsychotic action. So called "atypical" neuroleptics are mostly associated with a lower propensity for extrapiramidal side effects. It has been postulated that a low affinity and fast dissociation from the dopamine D2 receptor are important characteristics of atypicals. The neuroleptic drugs have been reported to act as inverse agonists at D2 receptors. It is suggested that this property may be important for the antipsychotic effects of drugs.