Molindone hydrochloride, a dihydroindolone neuroleptic, is structurally distinct 
from other classes of neuroleptics. Molindone exhibits many similarities to 
other neuroleptics, including dopamine receptor blockade, antipsychotic 
efficacy, and extrapyramidal side effects. Despite these similarities, molindone 
also has atypical properties and inhibits the enzyme monoamine oxidase in vitro 
and in vivo. Several studies have shown that molindone causes less dopamine 
receptor supersensitivity than other neuroleptics and thus may be less likely to 
cause tardive dyskinesia. It also appears to have a greater effect on mesolimbic 
and mesocortical dopamine neurons than on those in the nigrostriatal dopamine 
system. Clinically, molindone has a tendency to cause weight loss and may have 
less effect on seizure threshold than conventional antipsychotic agents. The 
authors review the laboratory and clinical data on molindone and discuss the 
relevance of atypical research findings to the clinical characteristics of this 
antipsychotic agent.