Psychometric assessment of subjective sleep quality using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J) in psychiatric disordered and control subjects
Y. Doi et al., Psychometric assessment of subjective sleep quality using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J) in psychiatric disordered and control subjects, PSYCHIAT R, 97(2-3), 2000, pp. 165-172
Subjective sleep quality has been identified as an important clinical const
ruct in psychiatric disordered patients. The Pittsburgh Sleep Quality Index
(PSQI), one of the most widely used standardized measures to assess subjec
tive sleep quality, generates a global score and scores seven components. T
he present study psychometrically assessed clinical profiles of subjective
sleep quality in 82 control and 92 psychiatric disordered subjects (primary
insomnia, n = 14; major depression, n = 30; generalized anxiety disorder,
n = 24; and schizophrenia, n = 24), using the Japanese version of the Pitts
burgh Sleep Quality Index (PSQI-J). The overall reliability coefficient of
the PSQI-J was high (Cronbach's alpha = 0.77). Correlation coefficients bet
ween the PSQI-J global and component scores were statistically significant.
The PSQI-J global and component mean scores were significantly higher in p
sychiatric disordered subjects than control subjects, except for the compon
ent of sleep duration. Using a cut-off point of 5.5 in the PSQI-J global sc
ore, estimations of sensitivity and specificity provided 85.7 and 86.6% for
primary insomnia, 80.0 and 86.6% fur major depression, 83.3 and 86.6% for
generalized anxiety disorder, and 83.3 and 86.6% for schizophrenia, respect
ively. The present study supports the utility of the PSQI-J as a reliable a
nd valid measure fur subjective sleep quality in clinical practice and rese
arch. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.