Investigating the appropriateness of the Pittsburgh Sleep Quality Index (PSQI) in a non-clinical Cypriot sample

1. Investigating the appropriateness of the Pittsburgh Sleep Quality Index (PSQI) in a non-clinical Cypriot sample Dr. Panayiotis Panayides

2. The PSQI is a self-rated instrument used to measure sleep quality in clinical samples. • Its development was based on: • psychiatrists’ clinical intuition • experience with sleep disorder patients • a review of other sleep quality questionnaires found in the literature and • clinical experience with the instrument during 18 months of field work. • (Buysse, Reynolds, MonK, Berman & Kupfer, 1989). • In order to: • to provide a reliable, valid, and standardized measure of sleep quality • to discriminate between “good” and “poor” sleepers • to provide an index that is easy for subjects to use and for clinicians and researchers to interpret and • to provide a brief, clinically useful assessment of a variety of sleep disturbances that might affect sleep quality. • (Buysse, Reynolds, MonK, Berman & Kupfer, 1989, p.194)

3. The PSQI Structure

4. The PSQI Items

6. The seven components Component 1: Subjective sleep quality = Score Q6 Q6. During the past month, how would you rate your sleep quality overall? Very good _____ Fairly good ______ Fairly bad ______Very bad ______ Component 2: Sleep latency = Score Q2 + Score Q5a • Q2. During the past month, how long (in minutes) has it usually taken you to fall asleep each night? • NUMBER OF MINUTES ___________ • 1 <=15, 2 16 – 30, 3 31 – 60, 4 >60 • Q5. During the past month, how often have you had trouble sleeping because you . . . • Cannot get to sleep within 30 minutes • 0 If sum = 0 • 1 If sum = 1 – 2 • 2 If sum = 3 – 4 • 3 If sum = 5 – 6 Component 3: Sleep duration = Score Q4 Q4. During the past month, how many hours of actual sleep did you get at night? (This may be different than the number of hours you spent in bed.) HOURS OF SLEEP PER NIGHT ___________ 0 > 7, 1 6 – 7, 2 5 – 6, 3 < 5

7. Component 4: Habitual Sleep Efficiency = 0 If >= 85%, 1 75 – 84% 2 65 – 74% 3 < 65% Component 5: Sleep Disturbances = Sum of score Q5b, …, Q5j (9 items) 0 If sum = 0 1 If sum = 1 – 9 2 If sum = 10 – 18 3 If sum = 19 – 27

8. Component 6: Use of Sleep Medication = Score Q7 Q7. During the past month, how often have you taken medicine to help you sleep (prescribed or "over the counter")? Component 7: Daytime Dysfunction = Score Q8 + Score Q9 Q8. During the past month, how often have you had trouble staying awake while driving, eating meals, or engaging in social activity? Q9. During the past month, how much of a problem has it been for you to keep up enough enthusiasm to get things done? 0 If sum = 0 1 If sum = 1 – 2 2 If sum = 3 – 4 3 If sum = 5 – 6

9. Another difference (between the PSQI and other instruments) is that these other questionnaires have used factor analysis to generate specific factors, while the PSQI components are empirical and clinical in origin rather than statistical (Buysse, Reynolds, MonK, Berman & Kupfer, 1989, p.203)

10. Other validation studies with samples of • elderly people (Buysse, Reynolds, Monk, Berman & Kupfer, 1991) • patients with AIDS (Rubinstein & Selwyn, 1998) • patients with panic disorders (Stein, Chartier, & Walker, 1993) • cancer patients (Beck et al., 2004) • patients with primary insomnia • (Backhaus, Junghanns, Broocks, Riemann & Hohagen, 2002) • bone marrow transplant patients and women with breast cancer • (Carpenter & AndryKowski, 1998) • Nigerian students (Aloba, Adewuya, Ola & Mapayi 2007). Only in one study Chien, Hsu, Tai, Guo and Su (2008) have used Rasch analyses to validate a revised version of the PSQI (9 items instead of the original 18).

11. The sample Stratified sampling(By area of residence urban or rural, age and gender) 415 (69.2%) lived in urban areas and 185 (30.8%) in rural areas + 15 depression patients (for validation purposes)

12. Rasch Rating Scale Diagnostics 1. Category frequencies Regular distributions (Uniform, Normal, Bimodal, slightly skewed) are preferable Low Frequencies do not provide enough observations for estimation of stable thresholds. Recommended min frequency 10 (Linacre 1999) 2. Average measures (a.m) Average of the ability estimates for all persons who choose that particular response category on any item in the scale. (Useful for quick observation of initial problems with the rating scale) They should increase monotonically, indicating that on average, those with higher ability / stronger attitude endorse the higher categories 3. Threshold or step calibrations Thresholds should also increase monotonically across the rating scale, otherwise they are considered disordered. Distances between threshold estimates should indicate that each step defines a distinct position on the variable. (i.e. should be neither too close together nor too far apart) Between 1.4 – 5 logits to avoid large gaps in the variable. (Linacre, 1999; Bond & Fox, 2001, p. 224) 4. Fit Statistics Outfit > 2 indicate more misinformation than information (Linacre, 1999), meaning that the category is introducing noise into the measurement process. Those categories warrant further empirical investigation and might be good candidates for collapsing with adjacent categories.

13. ANALYSES 1 – Component 5 (Sleep Disturbances, 9 items)

16. ANALYSES 2 – The seven Components Component 1: Subjective sleep quality Component 2: Sleep latency Component 3: Sleep duration Component 4: Habitual Sleep Efficiency Component 5: Sleep Disturbances Component 6: Use of Sleep Medication Component 7: Daytime Dysfunction

17. 1,99 - 0.19 - 1.32 15 out of the 21 3s 4 out of the 5 2s

20. Should component 6 be removed from the PSQI ? (in the case of using it in a non-clinical sample)

21. ANALYSES 3 – The whole PSQI 7. During the past month, how often have you taken medicine to help you sleep (prescribed or "over the counter")? 8. During the past month, how often have you had trouble staying awake while driving, eating meals, or engaging in social activity? 5e. During the past month, how often have you had trouble sleeping because you cough or snore loudly

23. 0123

24. 0122

25. 0112

26. Original 4-category model3-category models

27. 9 items 5 b) Wake up in the middle of the night or early in the morning 5 c) Have to get up to use the bathroom 5 de) Having breathing problems or snoring 5 fg) Feeling too cold or too hot 5 hij) Have any other problems (like pains, bad dreams, …. ) 5 items

28. PSQI 17 items13 misfitting persons 13(2.2%)removed 15(2.5%) Outfit > 2.30

29. 17 items 13 items 1.32 -0.66 0.66 1.76 -0.88 0.88

31. FINAL CALIBRATION

32. Use of sleep medication Staying awake Sleep efficiency How long to sleep, Too cold or too hot To keep enough enthusiasm Breathing or snoring Hours actual sleep, Can’t sleep 30 min, Rate Quality of Sleep Other reason Bathroom Wake up middle of night/early morning

33. Distinct Group Comparisons Depression patients vs Non-clinical subjects (Doi et al., 2000;Buysse, Reynolds, Monk, Berman and Kupfer, 1989) p = 0.000 Gender, with higher rate of complaints and worse quality of sleep found in women (Campbell, Gillin, Kripke, Erikson & Clopton, 1989; Lindberg, Janson, Gislason, Bjornsson, Hetta & Boman, 1997; Manni, Ratti, Marchioni, Castelnovo, Murelli, Sartori, Galimberti & Tartara, 1997). p = 0.000

34. Age, with older people having a higher sleep disorder rate (Foret, Bensimon, Benoit, & Vieux, 1981; Marquie and Foret, 1999)

35. People living in Urban areas vs Rural areas p = 0.022

36. THANK YOU FOR YOUR ATTENTION