Pittsburgh Sleep Quality Index

The Pittsburgh Sleep Quality Index (PSQI), developed by psychiatrist Buysse and colleagues at the University of Pittsburgh Medical Center in 1989, is among the most widely used sleep quality measures internationally and is described as a gold standard. It assesses sleep over the past month through 19 self-report items covering 7 areas: sleep quality, latency, duration, efficiency, disturbances, sleep medication, and daytime dysfunction. It is used for screening and supporting diagnosis of sleep disorders, objectively assessing sleep quality, tracking treatment outcomes, and epidemiological research.

PSQI has 7 components scored from 0–3, giving a total of 0–21. A total ≤7 indicates good sleep quality; >7 suggests poorer quality, with higher scores indicating greater difficulties. Components cover subjective sleep quality; time to fall asleep; actual sleep duration; efficiency (actual sleep/time in bed×100%); disturbances such as waking, nightmares, or pain; sleep medication; and daytime dysfunction such as drowsiness or low energy. Scores >7 warrant attention; >10 suggest a possible sleep disorder and a need for professional help.

PSQI suits adults of all ages, particularly people reporting insomnia, early waking, or poor sleep; patients being assessed or monitored for sleep disorders; people with mental disorders such as depression or anxiety; people with chronic conditions such as pain or cardiovascular disease; and general sleep health screening. Its one-month timeframe makes it useful for tracking changes. It is not designed for brief, acute problems such as one or two bad nights. Children and adolescents should use a dedicated child sleep measure.

Sleep efficiency = (actual sleep duration / time in bed) × 100%. For example, 6 hours of sleep during 8 hours in bed gives 75%. Scoring thresholds are >85%=0 (good), 75–84%=1, 65–74%=2, and <65%=3. Efficiency reflects quality as well as quantity. Low efficiency can suggest difficulty falling asleep, repeated waking, or early waking, and is an important indicator in insomnia assessment. Efficiency <85% suggests a need to improve sleep habits. A regular schedule, avoiding non-sleep activities in bed, and relaxation before bed can help.

Improving sleep quality is the key. ① Keep consistent bed and wake times, including weekends. ② Make the bedroom quiet, dark, and cool (18–22°C). ③ Go to bed only when sleepy and avoid phones or television in bed. ④ Avoid caffeine for 4–6 hours before bed and large amounts of fluid for 2 hours. ⑤ Exercise moderately each day, avoiding vigorous exercise within 3 hours of bed. ⑥ Try meditation, deep breathing, or progressive muscle relaxation. ⑦ Limit naps to 20–30 minutes. ⑧ Manage stress and stop work and electronic device use 1 hour before bed. If 4 weeks of these changes bring no improvement, seek sleep medicine or counseling support.

A PSQI total >7 warrants attention. Seek help promptly for: ① A total >10, suggesting a possible sleep disorder. ② Taking >30 minutes to fall asleep for over a month. ③ Efficiency <85%. ④ Sleep medication ≥3 times a week. ⑤ Severe daytime impairment, such as extreme drowsiness, concentration problems, or mood difficulties. ⑥ Problems lasting over 3 months, suggesting chronic insomnia. ⑦ Snoring, breathing pauses, or leg discomfort, which may suggest sleep-disordered breathing or restless legs syndrome. Start with a sleep specialist or counselor for comprehensive assessment and approaches such as CBT-I (cognitive behavioral therapy for insomnia). PSQI is a screening tool, not a replacement for diagnosis; a doctor must assess any sleep disorder comprehensively.