Categorical and Dimensional Approaches for Psychiatric Classification and Treatment Targeting: Considerations from...

Area of Science:

• Neuroscience
• Psychiatry
• Biomarkers

Background:

• Current psychiatric diagnostic systems, primarily symptom-based, face challenges in capturing the complexity of idiopathic psychoses.
• The debate between categorical and dimensional approaches for psychosis assessment and treatment persists.

Purpose of the Study:

• To investigate neurobiological distinctiveness among conventional psychosis diagnoses using cognitive and electrophysiological biomarkers.
• To identify biologically distinct subtypes of psychosis independent of current diagnostic categories.

Main Methods:

• The Bipolar Schizophrenia Network for Intermediate Phenotypes (B-SNIP) analyzed a large transdiagnostic psychosis dataset.
• Numerical taxonomy was employed to identify biological subtypes (Biotypes) based on cognitive and electrophysiological data.
• External validation was performed using independent samples and different measures.

Main Results:

• No neurobiological support was found for distinct conventional psychosis diagnoses; instead, a continuum of severity was observed.
• Three biologically distinct subtypes (Biotypes) were identified: Biotype-1 (reduced salient stimulus response), Biotype-2 (accentuated intrinsic neural activity, poor inhibition), and Biotype-3 (similar to healthy individuals).
• These Biotypes demonstrated external validity through differing imaging and electrophysiological measures and replicated in an independent cohort.

Conclusions:

• Biotype identification offers a novel, biologically-based approach to understanding psychosis heterogeneity, potentially improving treatment selection and outcome prediction.
• Preliminary findings suggest Biotype-1 may predict a better response to clozapine.
• Both categorical and dimensional approaches are crucial for optimizing diagnosis, care, and research in idiopathic psychoses.