Predictors of diagnostic stability in brief psychotic disorders: Findings from a 3-year longitudinal study

Brief psychotic disorder (BPD) is a relatively uncommon and underexplored psychotic condition. Even though BPD has been related to a more favorable outcome than other schizophrenia spectrum disorders (SSD), current knowledge of its predictive factors remains scant. This study aimed to examine its prevalence and find early predictors of BPD diagnostic stability.

SSD diagnosis following Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria was explored in a large epidemiological cohort (n = 569) of non-affective first-episode psychosis (FEP) patients enrolled in a three-year longitudinal intervention program (PAFIP). Premorbid, sociodemographic, and clinical information was collected to characterize BPD patients and determine factors predictive of diagnostic stability. Multivariate analysis included predictors selected from clinical knowledge and also those that had achieved marginal significance (p ≤ 0.1) in univariate analysis.

A total of 59 patients enrolled in the PAFIP program (10.4% of the whole cohort) met DSM-IV criteria for BPD, of whom 40 completed the three-year follow-up. The temporal stability of BPD in our sample was as high as 40% (n = 16). Transition from BPD to schizophrenia occurred in 37% (n = 15) of patients. Fewer hallucinations at baseline and better insight independently significantly predicted BPD diagnostic stability over time.

Our findings confirm that BPD is a clinical condition with moderate-to-low temporal stability and demonstrate that approximately two-thirds of FEP individuals experiencing BPD will develop a long-lasting psychotic disorder during follow-up, mainly schizophrenia.