The Inventory of Psychotic-Like Anomalous Self-Experiences (IPASE) shows strong construct validity as a self-report measure of minimal self-disturbance. In a sample of 46 participants including ultra-high risk and first-episode psychosis patients and healthy controls, the IPASE correlated very strongly (r = 0.92) with the gold-standard interview measure (EASE). It also correlated strongly with general psychopathology and positive psychotic symptoms, moderately with negative symptoms, and weakly with manic symptoms. The IPASE may serve as a screener but cannot replace the in-depth assessment of minimal self-disturbance, which requires clinical expertise.
Basic self-disturbance is a potential core vulnerability marker for schizophrenia spectrum disorders. The Self, Neuroscience and Psychosis (SNAP) study tests a neurophenomenological model of psychosis by examining clinical, neurocognitive, and neurophysiological variables in individuals at ultra-high risk (UHR) for psychosis. It includes 400 UHR individuals, 100 clinical controls without attenuated psychotic symptoms, and 50 healthy controls. Participants complete baseline assessments and electroencephalography; UHR participants are followed for 24 months with clinical assessments every 6 months. The protocol aims to develop a prediction model for persistence or worsening of UHR symptoms at 12 months and to determine how specific these disturbances are to attenuated psychotic symptoms.
Among 43 individuals at ultra-high risk for psychosis, those who later remitted had lower baseline levels of basic self-disturbance than those whose symptoms persisted or who transitioned to psychosis. Basic self-disturbance scores predicted worse clinical outcomes at 12 months. Source monitoring deficits were greater in first-episode psychosis patients than in those at ultra-high risk whose symptoms persisted or transitioned. The findings suggest that high levels of basic self-disturbance may serve as a predictor of poor prognosis in ultra-high risk patients.