2.1. Study Design
sleep disorders
DISORDER, MAY, CHRONIC INSOMNIA
A double-blinded, randomized, placebo-controlled trial was conducted at the Department of Obstetrics and Gynaecology, Faculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand, between November 2021 and May 2022. The study aimed to evaluate the effects of oral mixed tocopherol on postmenopausal chronic insomnia disorder. The results were measured by a subjective, self-evaluated questionnaire, the Pittsburgh Sleep Quality Index (PSQI), after one month of intervention. The PSQI was first developed in 1988 by Dr. Daniel J. Buysse and colleagues at the University of Pittsburgh. The questionnaire is intended to be a highly effective, standardized tool for assessing a patient’s sleep quality with a test reliability coefficient (Cronbach’s alpha) of 0.83, a sensitivity of 89.6%, and a specificity of 86.5% for sleep disorders [