Israel Medical Association Journal

Methods: We assessed 25 patients with insomnia who were enrolled in a hypnotic study but prior to the study were asked to undergo two full nights in lab polysomnography studies: with and without a placebo. Although they were not explicitly told that they were receiving a placebo, the participants knew that the results of these studies would determine whether they met the criteria to participate in the pharmaceutical study.

Results: Although the participants acknowledged that they were given a placebo, almost all measures of their sleep improved. With placebo, sleep latency was shortened from 55.8 ± 43.5 to 39.8 ± 58.5 minutes (P < 0.05); total sleep time was extended from 283 ± 72.5 to 362.9 ± 56.3 minutes, and sleep efficiency improved from 59.57 ± 14.78 to 75.5 ± 11.70% (P < 0.05). Interestingly, placebo had no effect on the relative sleep stage distribution (percentage of total sleep time), except for a trend toward increased percentage of REM[1] sleep.

Conclusions: Our findings how a clear and significant beneficial effect of placebo on insomnia, despite participants' understanding that they were receiving placebo. These results emphasize the importance of the patients' perception and belief in insomnia treatment, and suggest that in some cases placebo may serve as a treatment.

Background: The Pittsburgh Sleep Quality Index is a standardized self-administered questionnaire for the assessment of subjective sleep quality. It has been translated into several languages and is widely used in clinical research studies.

Objectives: To assess the reliability and validity of the Pittsburgh Sleep Quality Index Hebrew translation in a sleep clinic sample and in comparison with the Technion Mini Sleep Questionnaire.

Methods: The PSQI[1] was translated into Hebrew based on standard guidelines. The final Hebrew version (PSQI-H) was administered to 450 patients from two sleep clinics and to 61 healthy adults from the community as a non-clinical control sample. The MSQ[2] was administered to 130 patients in one sleep clinic.

Results: For the PSQI-H[3], Cronbach's-alpha scores for sleep clinic and non-clinical samples were 0.70 and 0.52 respectively and 0.72 combined. Clinical sample scores were significantly higher than the non-clinical group, indicating lower sleep quality for the former. Significant correlations were found between the MSQ subscores and PSQI-H component scores for common underlying constructs.

Conclusions: The PSQI-H differentiated between clinical and non-clinical samples and showed adequate reliability and good validity. It may be used as a standardized tool for the assessment of subjective sleep quality in clinical research studies conducted in the Hebrew-speaking population.