APSs linked to increased risk for psychiatric disorders
MedWire News: People who experience attenuated psychotic symptoms (APSs) are at increased risk for developing psychiatric disorders, particularly nonaffective psychotic disorders, study findings confirm.
Writing in the Archives of General Psychiatry, Mark Weiser (Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel) and team explain: "It has been suggested that APSs reported by people who do not have psychotic disorders signal risk for later severe mental illness."
"This… is supported by studies showing a link between APSs and nonaffective psychotic and, to a lesser extent, other psychiatric disorders."
They add: "Doubt may be expressed about the validity of these findings, however, as the measurements of psychotic disorders at follow-up in these studies were mostly based on lay-interviewer assessments using instruments such as the Composite International Diagnostic Interview, which is not an optimal instrument for the diagnosis of psychotic disorders."
To investigate further, the researchers studied data on 4914 individuals, aged 25 to 34 years, who were screened for psychopathology in the 1980s. At baseline, self-reports of APSs, such as delusions, hallucinations, bizarre thinking, feeling possessed, feeling that thoughts are not one's own, and beliefs of mind control, were assessed using the 13-item false beliefs and perceptions subscale of the Psychiatric Epidemiology Research Interview.
National registries were used to identify all those who were subsequently hospitalized for a psychiatric disorder over a mean follow-up period of 24 years.
Of the 4548 participants without diagnosable psychiatric disorder at baseline, 1187 reported no APSs, 2595 reported weak APSs, and 766 reported strong APSs in the year before assessment.
In total, 172 participants were hospitalized for a psychiatric disorder during follow-up.
After adjustment for age, gender, education, and ethnicity, the researchers found that participants with self-reported APSs at baseline were 4.31 times more likely to be hospitalized for a nonaffective psychotic disorder than those without APSs.
Participants with APSs were also more likely than those without to be hospitalized for any other type of psychiatric disorder, at an adjusted odds ratio of 2.21.
In terms of population attributable risk, 33.0% of hospitalizations for nonaffective psychotic disorder could be attributed, assuming causality, to the existence of APSs. The positive predictive value was 0.51% for weak APSs and 1.27% for strong APSs.
Weiser and team conclude: "Self-reported APSs signal risk for later nonaffective psychotic disorders but are not clinically useful as predictors."
They add: "Ultimately, greater understanding of the molecular and cognitive mechanisms of both APSs and psychotic disorders will lead to identification of clinically relevant biological markers predicting which person with an APS will go on to have a psychotic disorder, hence enabling early identification and intervention in psychotic illness."
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By Mark Cowen