The characterization of psychotic symptoms in succinic semialdehyde dehydrogenase deficiency: a review

Succinic semialdehyde dehydrogenase (SSADH) deficiency is an ultra-rare inborn error of metabolism that results in disrupted gamma-amino butyric acid (GABA) catabolism. In addition to developmental delay, intellectual disability, hypotonia, ataxia, and seizures, a variety of neuropsychiatric symptoms may occur, including psychosis. By highlighting all available and relevant case reports/series, this qualitative review seeks to characterize the prevalence, clinical manifestation, pathophysiology, and treatment of psychotic symptoms in this population. Psychosis occurs in a minority of SSADH-deficient individuals, and most commonly presents as auditory or visual hallucinations with an onset in adolescence or young adulthood. Although the pathophysiology underlying the development of psychosis in this context is not fully understood, it likely in part relates to increased GABA and/or gamma hydroxybutyric acid activity. Although antipsychotic medications should be used cautiously in SSADH deficiency, they may be effective at treating emergent psychotic symptoms.