Fluvoxamine may prevent onset of psychosis: a case report of a patient at ultra-high risk of psychotic disorder

Background: There is emerging evidence that antidepressants may be effective in preventing patients with nonspecific and psychotic-like prodromal symptoms, defined as patients at ultra-high risk (UHR) of psychotic disorder, from transitioning to psychosis. However, the mechanism of such an effect is still unknown. Methods: We report the case of a 19-year-old Japanese man determined to be at UHR of psychotic disorder in whom fluvoxamine (one of the antidepressants with sigma-1 receptor agonism) showed preventive effects on psychotic-like prodromal symptoms. Results: Our patient’s depressive symptoms were reduced and maintained below remission as a result of treatment with 100 mg/day of fluvoxamine. In addition, it is likely that an additional dose of fluvoxamine (50 mg/ day) improved his psychotic-like prodromal symptoms directly, independent of its antidepressive effects. Conclusion: Fluvoxamine, a sigma-1 receptor agonist, may be effective in preventing patients at UHR of psychotic disorder from onset of psychosis via its neuroprotective/neurotropic actions, independent of its antidepressive effects.