The factor structure of extrapyramidal symptoms evaluated using the Drug-Induced Extrapyramidal Symptoms Scale in patients with schizophrenia: Results from the 2016 REAP AP-4 study

Hum Psychopharmacol. 2023 Mar;38(2):e2861. doi: 10.1002/hup.2861. Epub 2022 Dec 3.

Abstract

Introduction: Drug-induced extrapyramidal syndrome (EPS) remains a major problem in clinical psychiatry. This study aimed to examine the factor structure of drug-induced extrapyramidal symptoms observed in patients with schizophrenia and assessed using the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS).

Methods: The participants were 1478 patients with a diagnosis of schizophrenia whose EPS was assessed using the DIEPSS in India, Indonesia, Japan, Malaysia, and Taiwan in the 2016 REAP AP-4 study. The records of the participants were randomly divided into two subgroups: the first for exploratory factor analysis of the eight DIEPSS items, and the second for confirmatory factor analysis.

Results: The factor analysis identified three factors: F1 (gait and bradykinesia), F2 (muscle rigidity and tremor), and F3 (sialorrhea, akathisia, dystonia, and dyskinesia).

Conclusion: The results suggest that the eight individual items of the DIEPSS could be composed of three different mechanisms: acute parkinsonism observed during action (F1), acute parkinsonism observed at rest (F2), and central dopaminergic mechanisms with pathophysiology other than acute parkinsonism (F3).

Keywords: DIEPSS; antipsychotics; extrapyramidal symptoms; schizophrenia.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antipsychotic Agents* / adverse effects
  • Basal Ganglia Diseases* / chemically induced
  • Basal Ganglia Diseases* / diagnosis
  • Basal Ganglia Diseases* / epidemiology
  • Humans
  • Japan
  • Parkinsonian Disorders* / chemically induced
  • Parkinsonian Disorders* / drug therapy
  • Schizophrenia* / drug therapy

Substances

  • Antipsychotic Agents