Dimensional structure of first episode psychosis

Area of Science:

• Psychiatry
• Clinical Psychology
• Mental Health Research

Background:

• Current diagnostic systems (DSM-5, ICD-10) use a categorical approach for psychotic disorders.
• A dimensional approach may better capture the complexity of psychotic symptomatology.

Purpose of the Study:

• To investigate the structure of psychotic symptoms in affective and non-affective psychosis using a dimensional approach.
• To identify distinct symptom clusters in first episode psychosis (FEP).

Main Methods:

• Recruited 257 participants with FEP from a randomized controlled trial (GET-UP PIANO TRIAL).
• Assessed participants using the Positive and Negative Syndrome Scale, Hamilton Depression Rating Scale, and Bech-Rafaelsen Mania Rating Scale.
• Performed a two-step cluster analysis to identify symptom dimensions.

Main Results:

• A robust four-cluster solution emerged: delusional-persecutory (31.9%), depressed (37%), excited (10.1%), and negative-disorganized (21%).
• This suggests a quadripartite structure encompassing both affective and non-affective dimensions.
• Negative and disorganization symptoms formed a unique construct separate from positive symptoms in non-affective dimensions.

Conclusions:

• Symptom dimensions provide a valuable tool for understanding the psychopathology of FEP.
• This dimensional approach can facilitate more targeted interventions for individuals with FEP.