Selenium compounds display neuroprotective activities mediated at least in part by their antioxidant actions. Oxidative damage has been implicated in psychiatric disorders including schizophrenia and bipolar disorder, and an alteration in expression of selenium-binding protein-1 (SELENBP-1) has been recently reported in both the blood and brain of schizophrenic patients. In the present study we examined the effects of the organic selenium compound 3'3-ditrifluoromethyldiphenyl diselenide [(F3CPhSe)2] on apomorphine-induced stereotypy in mice, an animal model of psychosis. Systemic administration of (F3CPhSe)2 at the highest dose used (25.0 micromol/kg in a 10.0 ml/kg injection volume) significantly reduced apomorphine-induced stereotyped behaviors. A series of control experiments showed that the same dose of (F3CPhSe)2 did not affect open-field behavior, habituation, or aversively motivated memory. The results indicate that organic selenium compounds should be further investigated as agents with possible antipsychotic properties.