Open AccessReliability of the Glasgow Antipsychotic Side-effects Scale for Clozapine Japanese version (GASS-C-J)
Author(s) -
Keisuke Kitagawa,
Ryuhei So,
Nobuyuki Nomura,
Yuya Mizuno,
Fuminari Misawa,
Masafumi Kodama,
Hiroyuki Uchida,
Masaru Mimura,
Hiroyoshi Takeuchi
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0234864
Subject(s) - hypersalivation , cronbach's alpha , medicine , clozapine , psychiatry , antipsychotic , brief psychiatric rating scale , nausea , schizophrenia (object oriented programming) , clinical psychology , psychology , psychosis , psychometrics , anesthesia
The purpose of this study was to develop the Glasgow Antipsychotic Side effects Scale for Clozapine Japanese version (GASS-C-J) and examine its reliability to assess clozapine-related side effects. We developed the GASS-C-J using forward and backward translation. Semantic equivalence of the GASS-C-J to the GASS-C was confirmed by the original author. We then administered the GASS-C-J twice to 109 patients on clozapine treatment at two psychiatric hospitals in Japan. We assessed the internal consistency and test-retest reliability of the GASS-C-J using Cronbach’s alpha and weighted kappa coefficient, respectively. We also examined if discrepancies in each GASS-C-J item score between the first and second rating were correlated with items of the Brief Evaluation of Psychosis Symptom Domains (BE-PSD). The Cronbach’s alpha coefficient of the GASS-C-J at the first and second rating was 0.78 (95% CI: 0.72 to 0.84) and 0.82 (95% CI: 0.76 to 0.88), respectively. The weighted kappa coefficient of individual and total GASS-C-J item scores ranged from 0.45 to 0.88. Some symptom domains were correlated with discrepancies in specific items of the GASS-C-J: psychotic symptoms and nausea/vomiting (r s = 0.27), thirst (r s = 0.31), and appetite/weight gain (r s = 0.27); disorganized thinking and urinary incontinence (r s = 0.26); depression/anxiety and myoclonus (r s = 0.25), hypersalivation (r s = -0.27), and blurred vision (r s = -0.22). These findings demonstrate that the GASS-C-J can be used in clinical and research settings as a reliable scale to assess clozapine-related side effects.