The North American Prodrome Longitudinal Study is a consortium of 8 academic centers (all but one in the U.S.) seeking to develop predictors of the devel- opment of psychosis in young patients who present with prodromal symptoms. Using the Structured Interview for Prodromal Syndromes (SIPS), researchers identified 291 subjects who met criteria for a “pro- dromal syndrome.” Most of the subjects meeting the prodromal critiera had “attenuat- ed positive symptoms.” Psychotic symptoms were defined as “attenuated” when patients were not completely convinced of the veracity of their delusions or hallucinations. The researchers then followed prodromal subjects for 2 1⁄2 years to see who would develop full-blown psychosis. The overall risk for conversion to psychosis over this time period was 35%. The investigators scanned their data in search of factors that were predictive. The most accurate predic- tions (74-81%) occurred when combining three factors: genetic risk for schizophrenia plus recent functional decline, unusual thought content, and either suspicion/paranoia or impaired social functioning (Cannon TD et al., Arch Gen Psychiatry 2008;65(1):28-37).
TCPR’s Take: These results garnered a fair amount of media attention, with headlines such as “Scientists Can Predict Psychotic Illness in up to 80 Percent of High-Risk Youth” (from NIH’s press release). But when you actually look at the study, these results are neither partic- ularly surprising nor very clinically useful. In order to be enrolled, patients were pretty close to being psychotic already, with significant psychotic ideation, defined as “prodromal” by the researchers. Chances are that most of these prodromal patients would have received treatment for psychosis if they had shown up in your office or mine. On the plus side, the study reminds us of the importance of certain factors, such as family history of schizophrenia and deteriorating social functioning, that we should make sure to explore systematically in at-risk patients.
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