Despite the prevalence of sleep complaints among psychiatric patients, few questionnaires have been specifically designed to measure sleep quality in clinical populations. The Pittsburgh Sleep Quality Index (PSQI) is a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval. Nineteen individual items generate seven “component” scores: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. The sum of scores for these seven components yields one global score. ##Scoring
| component | name | description |
| 1 | subjective sleep quality | Answer to q 6 |
| 2 | sleep latency | Scaled sum of number of minutes before sleep (q 2) and evaluation of sleep within 30min (q 5a), scaled to a 5 point scale |
| 3 | sleep duration | Scaled score of number of hours before one falls asleep (q 4), scaled to a 5 point scale |
| 4 | habitual sleep efficiency | hours of sleep (q 4) divided by bedtime (q 1) subtracted from rising time (q 3), and scaled to a 5 point scale |
| 5 | sleep disturbances | Sum of evaluation of sleep within 30min (q 5a) and all remaining questions on sleep problems (q 5b-j), scaled to a 5 point scale |
| 6 | use of sleeping medication | Answer to question on use of sleep medication (q 7) |
| 7 | daytime dysfunction | Sum of evaluation of staying awake (q 8) and evaluation of keeping enthusiastic (q 9), scaled to a 5-point scale |
| global score | sum of the above. | If any of the above is not possible to calculate, the global sum is also not calculated |
Questions with multiple subquestions should be named in a similar manner, suffixed by the alphabetical index (psqi_5a, psqi_5b etc.). For questions 5j and 10j, the frequency of occurence should have the names psqi_5j and psqi_10e, and the freehand explanations should have any type of suffix after this to indicate a text answers (i.e. psqi_5j_Desc or psqi_5j_string, psqi_5j_freehand). As an example, LCBC has the following set-up:
psqi_1
psqi_2
psqi_3
psqi_4
psqi_5a psqi_5b psqi_5c psqi_5d psqi_5e psqi_5f psqi_5g psqi_5h psqi_5i psqi_5j psqi_5j_Coded psqi_5j_Desc
psqi_6
psqi_7
psqi_8
psqi_9
psqi_10 psqi_10a psqi_10b psqi_10c psqi_10d psqi_10e psqi_10e_Desc psqi_10e_Coded
psqi_11a psqi_11b psqi_11c psqi_11d
Buysse et al. (1989) The Pittsburgh sleep quality index: A new instrument for psychiatric practice and research, Psychiatry Research, 28:2, 193-213
psqi_compute_comp2(min_before_sleep, no_sleep_30min)
psqi_compute_comp3(hours_sleep)
psqi_compute_comp4(hours_sleep, bedtime, risingtime, ...)
psqi_compute_comp5(data, sleep_troubles = matches("^psqi_05[b-j]$"))
psqi_compute_comp7(keep_awake, keep_enthused)
psqi_compute_global(data, cols = matches("comp[1-7]+_"), max_missing = 0)
psqi_compute(
data,
components = 1:7,
bedtime = psqi_01,
min_before_sleep = psqi_02,
risingtime = psqi_03,
hours_sleep = psqi_04,
no_sleep_30min = psqi_05a,
sleepquality = psqi_06,
medication = psqi_07,
keep_awake = psqi_08,
keep_enthused = psqi_09,
sleep_troubles = matches("^psqi_05[b-j]$"),
max_missing = 0,
...,
prefix = "psqi_",
keep_all = TRUE
)column name with no. minutes before sleep (numeric) (psqi_02)
column name with evaluation of sleep within 30min (0-3) (psqi_05a)
column name with hours of sleep (decimal hours) (psqi_04)
column name with bedtime (HH:MM:SS) (psqi_01)
column name with rising time (HH:MM:SS) (psqi_03)
other arguments to psqi_compute_time_in_bed
data frame
columns containing sleep problem evaluations (0-3) (psqi_05(b-j) )
column name with evaluation of staying awake (0-3) (psqi_08)
column name with evaluation of keeping enthusiastic (0-3) (psqi_09)
columns containing the components
Integer specifying the number of missing values to accept in the PSQI components,
before the global PSQI value is set to missing. Defaults to 0. If max_missing > 0, the
global PSQI value is computed by weighting each non-missing entry with 7 / (7 - max_missing).
integer vector of components to calculate. If all 7, global is added also
column name with evaluation of sleep quality (0-3) (psqi_06)
column name with use of sleep mediation (0-3) (psqi_07)
string to prefix column names of computed values
logical, append to data.frame
a data.frame containing only the calculated components
psqi_compute_comp2(): calculate the component 2 (sleep latency)
psqi_compute_comp3(): calculate the component 3 (sleep duratione)
psqi_compute_comp4(): calculate the component 4 (habitual sleep efficiency)
psqi_compute_comp5(): calculate the component 5 (sleep disturbance)
psqi_compute_comp7(): calculate the component 7 (daytime dysfunction)
psqi_compute_global(): calculate the global scores, sum of all components