PSQI Sleep Quality Index

What the PSQI measures

The Pittsburgh Sleep Quality Index (PSQI), developed by Buysse and colleagues and published in Psychiatry Research in 1989, is the gold-standard self-report measure of sleep quality. Unlike single-question measures ("How did you sleep?"), the PSQI assesses 7 distinct components of sleep over the past month: subjective sleep quality, sleep latency, sleep duration, sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction. The total score ranges from 0 to 21, with higher scores indicating worse sleep quality.

The 7 components

Subjective sleep quality, your overall rating of sleep. Sleep latency, how long it takes to fall asleep. Sleep duration, total hours of actual sleep. Sleep efficiency, time asleep divided by time in bed (×100). Sleep disturbances, frequency of problems like waking in the night, pain, breathing issues, coughing. Sleep medication use, frequency of prescription or over-the-counter sleep aids. Daytime dysfunction, trouble staying awake during the day and difficulty maintaining enthusiasm for activities.

The critical cutoff: >5 = poor sleeper

A PSQI score >5 distinguishes poor from good sleepers with a sensitivity of 89.6% and specificity of 86.5%. This cutoff was established in the original validation study and has been confirmed across dozens of populations. Scores of 6-10 indicate moderate sleep problems, while scores >10 indicate severe sleep difficulties that warrant clinical evaluation.

Sleep quality vs. sleep disorders

The PSQI measures sleep quality, how well you sleep, not whether you have a specific sleep disorder. A high PSQI score could reflect insomnia, sleep apnea, restless legs syndrome, circadian rhythm disorder, or simply poor sleep habits. If your PSQI is elevated, discuss the results with your clinician, who can determine whether further evaluation (sleep study, actigraphy) is needed. Common causes of poor PSQI scores include: irregular sleep schedule, excessive screen time before bed, caffeine after noon, alcohol before bed, untreated sleep apnea, chronic stress, and depression/anxiety.

CBT-I, the most effective treatment for insomnia

Cognitive Behavioral Therapy for Insomnia (CBT-I) is the first-line treatment recommended by the American College of Physicians for chronic insomnia. It is more effective than sleep medication in the long term and does not have the risks of dependence or side effects. CBT-I typically involves: sleep restriction (limiting time in bed to actual sleep time), stimulus control (using the bed only for sleep), cognitive restructuring (addressing sleep-related anxiety), and sleep hygiene education. Most patients see improvement within 4-6 sessions. CBT-I apps and online programs (e.g. Sleepio, SHUTi) are also effective.

Sleep hygiene basics

Regardless of PSQI score, everyone benefits from good sleep hygiene: maintain a consistent sleep/wake time (even on weekends), keep the bedroom cool (65-68°F, about 18-20°C), dark, and quiet, avoid screens for 1 hour before bed (or use blue-light filters), limit caffeine after noon, avoid alcohol within 3 hours of bed (it disrupts REM sleep), exercise regularly but not within 3 hours of bed, and don't lie in bed awake for more than 20 minutes, get up and do a quiet activity until sleepy. If poor sleep persists despite good hygiene, discuss with your clinician.