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

BackgroundThe 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.MethodsA 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.ResultsTwenty-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.ConclusionsThe 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. © The Author 2012. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved.