The recent cloning and identification of the D3 receptor has attracted interest. Its localisation in the limbic areas suggests it may play a role in cognitive and emotional functions and so be an important target for antipsychotic drug therapy. This hypothesis is supported by findings that antipsychotic drugs previously thought to be selective for D2 receptors (raclopride and pimozide), as well as nonselective antipsychotic drugs (flupenthixol and chlorpromazine) and the atypical drug, clozapine, all interact with D3 receptors. If blockade of D3 receptors is involved in antipsychotic effects, then selective D3 antagonists may well provide antipsychotic drug therapy free from motor and hormonal adverse effects. Conversely, the use of dopamine agonists free of D3 activity in Parkinson's disease would be predicted to reduce the incidence of psychosis-like adverse effects.