Transdiagnostic Symptom Dimensions in Individuals at Ultra-High Risk for Psychosis: Towards Dimensional...

Area of Science:

• Psychiatry
• Psychology
• Clinical Neuroscience

Background:

• Research is shifting towards dimensional rather than categorical views of mental health.
• High overlap exists between psychosis spectrum and affective disorders, challenging traditional diagnostic boundaries.
• Transdiagnostic dimensions of psychopathology are understudied in youth at ultra-high risk for psychosis.

Purpose of the Study:

• To investigate a general dimension underlying psychopathological symptoms in at-risk youth.
• To determine if specific symptom dimensions (positive, negative, affect, activation) are justified alongside a general dimension.

Main Methods:

• Item factor analyses were performed on Brief Psychiatric Rating Scale (BPRS) symptom ratings.
• Data were collected at baseline from the Staged Treatment in Early Psychosis (STEP) trial.
• 342 participants at ultra-high risk for psychosis (UHR) were included.

Main Results:

• A bifactor model with one general dimension and four specific factors (positive, negative, affect, activation) showed the best relative fit.
• Model stability and interpretability suggest differentiation between pluripotent and domain-specific symptom patterns.
• Absolute model fit statistics did not strongly support the bifactor model.

Conclusions:

• The BPRS may indicate both a general and specific dimensions of psychopathology in UHR youth.
• Findings cautiously support a 'common ground' or transdiagnostic phenotype in this heterogeneous sample.
• This dimensional approach may help differentiate symptom patterns preceding first-episode psychosis.