Predictors of diagnostic stability in acute and transient psychotic disorders: validation of previous findings and implications for ICD-11

Acute and transient psychotic disorders (ATPD) have moderate prospective diagnostic stability. Female gender, older age at onset, good premorbid adjustment, abrupt onset, shifting polymorphic symptomatology and absence of schizophrenic features have been found to be predictive factors of diagnostic stability in ATPDs. Nevertheless, most of these findings need to be replicated. The purpose of this study was to evaluate the diagnostic stability of patients with ATPD, and to determine whether previously accepted predictors of diagnostic stability for ATPD could be externally validated in our cohort. To that end, a prospective 2-year observational study was conducted on patients with first-episode ATPD. Multivariate analysis was performed to determine factors associated with ATPD diagnostic stability at the end of the follow-up period. The following prior knowledge variables were analyzed: female gender, older age at onset, good premorbid adjustment, abrupt onset, shifting polymorphic symptomatology and absence of schizophrenic features. Sixty-eight patients with first-episode ATPD completed the follow-up, of whom 55.9% (n = 38) retained their diagnosis of ATPD at the end of the study. Multivariate analysis revealed that diagnostic stability was independently significantly associated with the presence of shifting polymorphic symptomatology (OR = 7.42, 95% CI 1.65-33.30; p = 0.009) and the absence of schizophrenic features (OR = 6.37, 95% CI 1.47-27.54; p = 0.013) at the onset of the psychotic disorder. Our findings provide empirical support for the ICD-11 proposal restricting the new ATPD category to the acute polymorphic disorder without schizophrenia symptoms.