Schizophrenia in the internalizing-externalizing framework: a third dimension?

Area of Science:

• Psychiatry
• Clinical Psychology
• Mental Health Research

Background:

• Previous research identified internalizing and externalizing spectra in community adults.
• The placement of schizophrenia and schizotypal personality disorder within these spectra was unexplored in clinical settings.

Purpose of the Study:

• To investigate the classification of schizophrenia and schizotypal personality disorder within existing mental illness spectra.
• To test the validity of a revised mental illness organization in a clinical patient population.

Main Methods:

• Utilized data from the Suffolk County Mental Health Project cohort (N=469) of first-admission psychosis patients.
• Diagnoses were made by mental health professionals using semistructured interviews, record reviews, and collateral reports over 10 years.
• Validators included family history of schizophrenia and 10-year illness course.

Main Results:

• Confirmatory factor analysis showed the Diagnostic and Statistical Manual of Mental Disorders-IV grouping fit the data poorly.
• A three-cluster model (internalizing, externalizing, schizophrenic) demonstrated a superior fit.
• Both validators supported the coherence and distinctiveness of the identified schizophrenic cluster.

Conclusions:

• Replicated internalizing and externalizing spectra in a clinical sample.
• Identified and provided initial validity evidence for a distinct schizophrenic spectrum.
• Suggests reclassifying schizotypal personality disorder with schizophrenia, antisocial disorders with substance use disorders, and major depression with anxiety disorders.