Association between probable postictal psychosis and subsequent diagnosis of primary psychotic disorders: a retrospective cohort study.

RATIONALE: Postictal psychosis (PIP) is a transient psychiatric phenomenon characterised by psychotic symptoms following a seizure. While its immediate manifestations have been well documented, there is limited understanding of its long-term implications, particularly its relationship with subsequent primary psychotic disorders. METHODS: We conducted a retrospective cohort study using de-identified patient data from the TriNetX database (2006-2026). Individuals aged 18-65 years with a diagnosis of probable PIP (International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM): F06.0, F06.2) or brief psychotic disorder within 7 days of the epileptic disorder diagnosis (ICD-10-CM: F23) were propensity-score matched 1:1 with controls without PIP based on age, sex, race, ethnicity and relevant psychiatric and chronic physical comorbidities. We excluded individuals with prior psychotic disorders or delirium. The primary outcome was any psychotic disorder diagnosis within a 5-year follow-up period. Kaplan-Meier survival analyses and HRs were calculated to assess the differences in survival probabilities. RESULTS: A total of 1275 individuals were identified and matched for analysis. Patients with probable PIP were at significantly higher risk for subsequent psychotic disorders (HR=10.78, 95% CI 6.21 to 18.70, p=0.002). The 5-year survival probability for developing any psychotic disorder was 85.79% in the probable PIP group compared with 98.21% in controls (log-rank test, χ2=112.25; p<0.0001). CONCLUSIONS: Probable PIP is associated with a heightened risk of subsequent primary psychotic disorders, including interictal forms, within 5 years.