Revisiting Delusion Subtypes in Schizophrenia Based on Their Underlying Structures

Authors

Andrew D van der Vaart
Yizhou Ma
Joshua Chiappelli
Heather Bruce
Mark D Kvarta
Alia Warner
Xiaoming Du
Bhim M Adhikari
Hemalatha Sampath
Peter Kochunov
L Elliot Hong

Publication Date

3-1-2024

Journal

Journal of Psychiatric Research

Abstract

A clear understanding of the pathophysiology of schizophrenia and related spectrum disorders has been limited by clinical heterogeneity. We investigated whether relative severity and predominance of one or more delusion subtypes might yield clinically differentiable patient profiles. Patients (N = 286) with schizophrenia spectrum disorders (SSD) completed the 21-item Peters et al. Delusions Inventory (PDI-21). We performed factor analysis followed by k-means clustering to identify delusion factors and patient subtypes. Patients were further assessed via the Brief Psychiatric Rating Scale, Brief Negative Symptom Scale, Digit Symbol and Digit Substitution tasks, use of cannabis and tobacco, and stressful life events. The overall patient sample clustered into subtypes corresponding to Low-Delusion, Grandiose-Predominant, Paranoid-Predominant, and Pan-Delusion patients. Paranoid-Predominant and Pan-Delusion patients showed significantly higher burden of positive symptoms, while Low-Delusion patients showed the highest burden of negative symptoms. The Paranoia delusion factor score showed a positive association with Digit Symbol and Digit Substitution tasks in the overall sample, and the Paranoid-Predominant subtype exhibited the best performance on both tasks. Grandiose-Predominant patients showed significantly higher tobacco smoking severity than other subtypes, while Paranoid-Predominant patients were significantly more likely to have a lifetime diagnosis of Cannabis Use Disorder. We suggest that delusion self-report inventories such as the PDI-21 may be of utility in identifying sub-syndromes in SSD. From the current study, a Paranoid-Predominant form may be most distinctive, with features including less cognitive impairment and a stronger association with cannabis use.

Keywords

Humans, Schizophrenia, Delusions, Mood Disorders, Brief Psychiatric Rating Scale, Delusions, Diagnosis, Factor analysis, Monothematic vs. Pan-thematic, Paranoia, Schizophrenia.

DOI

10.1016/j.jpsychires.2023.12.025

PMID

38246028

PMCID

PMC10923062

PubMedCentral® Posted Date

3-1-2025

PubMedCentral® Full Text Version

Author MSS

Published Open-Access

yes