At risk for schizophrenic or affective psychoses? A meta-analysis of DSM/ICD diagnostic outcomes in individuals at high clinical risk

Abstract

Background: The clinical high-risk state for psychosis (HRP) is associated with an enhanced probability of developing a psychotic episode over a relatively short period of time. However, the extent to which different diagnostic types of illness develop remains unclear.

Methods: A systematic review was performed to identify studies of HRP participants reporting International Classfication of Diseases/Diagnostic and Statistical Manual of Mental Disorders diagnostic outcomes at follow-up. Demographic, clinical, and methodological variables were extracted from each publication or obtained directly from its authors. A meta-analysis was performed of transition to schizophrenic (SP) or affective psychoses (AP) and to specific diagnostic categories. Statistical heterogeneity and small study bias were assessed, and meta-regressions were performed.

Results: Twenty-three studies were retrieved, including a total of 2182 HRP participants, 560 (26%) of them developed a frank psychotic disorder over the follow-up time (mean = 2.35 y). Among HRP participants who developed psychosis, 73% were diagnosed with SP and only 11% with AP (Risk Ratio, RR = 5.43, 95% CI from 3.35 to 8.83). The specific transition risk to ICD/DSM schizophrenia was of 15.7% (over 2.35y). Heterogeneity was statistically significant and moderate in magnitude. Use of basic symptoms criteria in the baseline clinical assessment was associated with a further increase in the proportion progressing to SP vs AP (RR = 17.1). There was no evidence of publication bias and the sensitivity analysis confirmed robustness of the above results.

Conclusions: The HRP state is heterogeneous in term of longitudinal diagnoses; however, the current HRP diagnostic criteria appear strongly biased toward an identification of early phases of SP rather than AP.

Keywords: ARMS; BS; SIPS; affective psychosis; bipolar; high risk; prodromal; psychosis; schizophrenia.

Fig. 1.

PRISMA flow-chart of search strategy used for the inclusion of the studies considered in the current meta-analysis.

Fig. 2.

Descriptive analysis of International Classification of Diseases /Diagnostic and Statistical Manual of Mental Disorders diagnoses in the high-risk subjects who later developed a frank psychotic episode (n = 560). Specific meta-analytical risk estimates across the different diagnostic categories are reported in table 2.

Fig. 3.

Meta-analysis of transition risk ratio in the HRP state: affective psychoses (AP) vs schizophrenic psychoses (SP). Random effect models applied.