PSQI — Pittsburgh Sleep Quality Index Calculator

About

The Pittsburgh Sleep Quality Index (PSQI) was developed by Buysse et al. at the University of Pittsburgh in 1989. It is a 19-item self-administered questionnaire that generates 7 component scores: subjective sleep quality, sleep latency (time to fall asleep), sleep duration, sleep efficiency (actual sleep time / time in bed), sleep disturbances, use of sleep medication, and daytime dysfunction. Each component is scored 0-3, yielding a global PSQI score from 0-21. The PSQI has excellent psychometric properties with a sensitivity of 89.6% and specificity of 86.5% at the cutoff of >5 for distinguishing good from poor sleepers. Test-retest reliability is high (Pearson r=0.85), and internal consistency is good (Cronbach alpha 0.80-0.83). The PSQI has been validated in multiple populations including primary insomnia, sleep apnea, depression, PTSD, chronic pain, cancer patients, and elderly populations. It has been translated into over 50 languages. The PSQI is widely used as an outcome measure in clinical trials of insomnia treatments, CPAP therapy, and interventions for sleep disorders. The PSQI addresses seven clinically relevant domains of sleep over the past month, providing a comprehensive yet efficient assessment of sleep quality.

Formula

PSQI Global Score = Sum of 7 component scores (0-3 each). Range: 0-21. Higher scores indicate worse sleep quality. Cutoff: >5 = poor sleep quality.

The PSQI global score is the sum of 7 component scores, each scored 0-3. Component 1 (Sleep Quality): derived from question 6. Component 2 (Sleep Latency): derived from questions 2 and 5a. Component 3 (Sleep Duration): derived from question 4. Component 4 (Sleep Efficiency): calculated as (hours slept / hours in bed) × 100, scored 0 (≥85%) to 3 (<65%). Component 5 (Sleep Disturbances): derived from questions 5b-5j. Component 6 (Sleep Medication): derived from question 7. Component 7 (Daytime Dysfunction): derived from questions 8 and 9. A global PSQI score >5 indicates poor sleep quality with sensitivity of 89.6% and specificity of 86.5%. The PSQI is not a diagnostic tool for specific sleep disorders but rather a screening instrument for overall sleep quality. In research, a 3-point change in PSQI global score is considered a minimal clinically important difference.

Score Interpretation

The Pittsburgh Sleep Quality Index (PSQI) is the most widely used standardized measure of sleep quality in clinical research and practice. Its clinical significance is supported by over 30 years of validation across diverse populations. The PSQI demonstrates excellent diagnostic properties at the cutoff of >5, with pooled sensitivity of 89.6% and specificity of 86.5% for distinguishing poor from good sleepers. Test-retest reliability is high (r=0.85), and internal consistency is good (Cronbach alpha 0.80-0.83). The PSQI has been validated in numerous clinical populations including: primary insomnia (sensitivity 98.7%, specificity 84.4%), obstructive sleep apnea, restless legs syndrome, depression (sensitivity 93%, specificity 82%), PTSD, chronic pain syndromes, fibromyalgia, cancer patients undergoing chemotherapy, Parkinson's disease, Alzheimer's disease, and shift workers. The PSQI has been translated into over 50 languages and is used worldwide as both a screening tool and outcome measure. The PSQI is recommended by the American Academy of Sleep Medicine (AASM) as a clinical tool for sleep quality assessment and is widely used in NIH-funded research. The PSQI global score correlates moderately with objective sleep measures from polysomnography (PSG), particularly sleep efficiency (r=-0.40 to -0.50) and total sleep time (r=0.30-0.40). The seven component scores provide clinically useful information about specific domains of sleep disturbance, enabling targeted interventions. The minimal clinically important difference (MCID) for the PSQI global score is approximately 3 points.

Reference Ranges