PCL-6

PTSD Checklist 6 (PCL-6)

Measuring: A screening tool for posttraumatic stress disorder (PTSD).

Number of Items: 6

Item	Question Wording	TILDA Variable
1	Repeated, disturbing memories, thoughts or images of a stressful experience from the past?	SCQPCL1
2	Feeling very upset when something reminded you of a stressful experience from the past?	SCQPCL2
3	Avoided activities or situations because they reminded you of a stressful experience from the past?	SCQPCL3
4	Feeling distant or cut off from other people?	SCQPCL4
5	Feeling irritable or having angry outbursts?	SCQPCL5
6	Difficulty concentrating?	SCQPCL6

Scoring Method:

5-point Likert scale

1 = Not at all

2 = A little bit

3 = Moderately

4 = Quite a bit

5 = Extremely

Score are cumulated within each subscale, with higher scores indicating a greater use of that particular coping strategy (6-30).

Citation: Lang, A.J., Stein, M.B. (2005) An abbreviated PTSD checklist for use as a screening instrument in primary care. Behaviour Research and Therapy, 43, 585-594.

Code

* PTSD Checklist 6 (PCL-6)


mvdecode SCQPCL1-SCQPCL6, ///
    mv(-99=. \ -812=. \ -823=. \ -834=. \ -845=.)

* Total score: 6-30
egen PCL6Score = rowtotal(SCQPCL1-SCQPCL6)

* Require all 6 items to be answered
egen PCL6_missing = rowmiss(SCQPCL1-SCQPCL6)
replace PCL6Score = . if PCL6_missing > 0

label variable PCL6Score "PTSD Checklist 6 (PCL-6) total score"

* Positive PTSD screen using cut-off >=14
gen PCL6_screen = .
replace PCL6_screen = 0 if PCL6Score < 14 & PCL6Score != .
replace PCL6_screen = 1 if PCL6Score >= 14 & PCL6Score != .

label define PCL6_screen ///
    0 "Negative screening (<14)" ///
    1 "Positive screening (14+)"
label values PCL6_screen PCL6_screen

label variable PCL6_screen "PCL-6 probable PTSD screen"

tab PCL6_screen, missing
summarize PCL6Score

Download Stata .do file

pcl_items <- paste0("SCQPCL", 1:6)

for (var in pcl_items) {
  data[[var]][data[[var]] %in% c(-99, -812, -823, -834, -845)] <- NA
}

# Total score: 6-30.
# Stata rowtotal() is used first, then the score is set missing if any item is missing.
data$PCL6Score <- rowSums(data[pcl_items], na.rm = TRUE)
data$PCL6_missing <- rowSums(is.na(data[pcl_items]))
data$PCL6Score[data$PCL6_missing > 0] <- NA_real_

attr(data$PCL6Score, "label") <- "PTSD Checklist 6 (PCL-6) total score"

# Positive PTSD screen using cut-off >=14.
data$PCL6_screen <- NA_real_
data$PCL6_screen[!is.na(data$PCL6Score) & data$PCL6Score < 14] <- 0
data$PCL6_screen[!is.na(data$PCL6Score) & data$PCL6Score >= 14] <- 1

attr(data$PCL6_screen, "label") <- "PCL-6 probable PTSD screen"
attr(data$PCL6_screen, "labels") <- c(
  "Negative screening (<14)" = 0,
  "Positive screening (14+)" = 1
)

print(table(data$PCL6_screen, useNA = "ifany"))
summary(data$PCL6Score)

Download R file

RECODE SCQPCL1 TO SCQPCL6
    (-99 = SYSMIS)
    (-812 = SYSMIS)
    (-823 = SYSMIS)
    (-834 = SYSMIS)
    (-845 = SYSMIS).

* Stata rowtotal() followed by complete-case requirement.
COMPUTE PCL6Score = SUM(SCQPCL1, SCQPCL2, SCQPCL3, SCQPCL4, SCQPCL5, SCQPCL6).
COUNT PCL6_missing = SCQPCL1 SCQPCL2 SCQPCL3 SCQPCL4 SCQPCL5 SCQPCL6 (MISSING).
IF (PCL6_missing > 0) PCL6Score = $SYSMIS.

VARIABLE LABELS PCL6Score "PTSD Checklist 6 (PCL-6) total score".

COMPUTE PCL6_screen = $SYSMIS.
IF (NOT MISSING(PCL6Score) AND PCL6Score < 14) PCL6_screen = 0.
IF (NOT MISSING(PCL6Score) AND PCL6Score >= 14) PCL6_screen = 1.

VALUE LABELS PCL6_screen
  0 "Negative screening (<14)"
  1 "Positive screening (14+)".

VARIABLE LABELS PCL6_screen "PCL-6 probable PTSD screen".

FREQUENCIES VARIABLES=PCL6_screen /MISSING=INCLUDE.
DESCRIPTIVES VARIABLES=PCL6Score.

EXECUTE.

Download SPSS .sps file