Prevalence of attenuated psychotic symptoms and their relationship with DSM-IV diagnoses in a general psychiatric outpatient clinic

Abstract

Objective: Attenuated psychosis syndrome (APS) is being proposed for inclusion in Section III of DSM-5 for those impaired by subthreshold psychotic symptoms that are not better accounted for by another diagnosis and not meeting criteria for a psychotic disorder. The rationale is to identify patients who are at high risk for transition to a psychotic disorder in the near future. However, the potential impact of using this new diagnosis in routine clinical practice settings has not been carefully examined.

Method: As part of the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, a treatment-seeking psychiatric outpatient sample (n = 1,257) recruited from June 1997 to June 2002 completed a self-report measure of psychiatric symptoms and afterward were administered structured clinical interviews. For the current post hoc study, we investigated the prevalence rate of endorsing attenuated psychotic experiences to identify patients who could potentially meet criteria for APS.

Results: After the exclusion of those with lifetime DSM-IV psychotic disorders, psychotic experiences remained highly prevalent in the sample (28% reported at least 1 psychotic experience during the past 2 weeks), and rates were similar across all major DSM-IV diagnostic categories. Only 1 patient (0.08%) reported psychotic experiences but did not meet criteria for another current DSM disorder; however, this individual endorsed other nonpsychotic symptoms of greater severity. Psychotic experience endorsement was positively correlated with nearly all other nonpsychotic symptom domains, and multivariate analysis showed that general clinical severity predicted endorsement of psychotic experiences (P values < .001).

Conclusions: We could not identify any patients who clearly met criteria for APS alone in our sample. Psychotic experiences appear to be common in outpatients and represent nonspecific indicators of psychopathology. Diagnosing APS in the community could result in high rates of false-positives or high rates of APS "comorbidity" with other nonpsychotic disorders, leading to the increased use of antipsychotic medications without clear need. Therefore, the clinical utility of adding APS to the diagnostic system remains highly questionable.