A new short version of the Posttraumatic Diagnostic Scale: validity among Japanese adults with and without PTSD

Figures & data

Table 1. Proportion of participants who answered the re-experiencing symptoms among Japanese participants with and without PTSD.

			CAPS (DSM-IV)
			PTSD+ n = 97	PTSD- n = 72
Criteria in DSM-IV	Re-experiencing symptoms of PTSD	Overall N = 169	% in each group
B1	Intrusive images	119	96.91	34.72
B2	Nightmares	92	88.66	8.33
B3	Reliving of the trauma	88	79.38	15.28
B4	Emotionally upset when reminded of the trauma	131	98.97	48.61
B5	Physiological reactions when reminded of the trauma	113	96.91	26.39

PTSD, posttraumatic stress disorder; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, 4th ed.; CAPS, Clinician-Administered PTSD Scale. PTSD+ indicates that participants met CAPS-diagnosed PTSD criteria.

Table 2. Characteristics of the study participants.

	Clinical subsample		Non-clinical subsample
Variable	(n = 106)		(n = 63)
Age, years (standard deviation)	35.87	(8.5)	20.51	(2.2)
Female, n (%)	106	(100)	31	(49.2)
Index trauma, n (%)
Accident or fire	1	(0.9)	13	(20.6)
Natural disaster	1	(0.9)	6	(9.5)
Nonsexual assault (known assailant)	57	(53.8)	6	(9.5)
Nonsexual assault (unknown assailant)	1	(0.9)	2	(3.2)
Sexual assault (known assailant)	25	(23.6)	4	(6.3)
Sexual assault (unknown assailant)	14	(13.2)	6	(9.5)
Combat or war zone	0	(0)	0	(0)
Sexual abuse	2	(1.9)	5	(7.9)
Imprisonment	3	(2.8)	2	(3.2)
Torture	1	(0.9)	0	(0)
Life-threatening illness	1	(0.9)	1	(1.6)
Other	12	(11.3)	18	(28.6)
PTSD diagnosis, n (%)	94	(88.7)	3	(4.8)

Index trauma was self-rated via the Posttraumatic Diagnostic Scale and confirmed to be the same with what was obtained through the Clinician-Administered PTSD Scale (CAPS) interview. Some participants indicated that more than one event disturbed them the most; PTSD, posttraumatic stress disorder diagnosed via the CAPS. Other traumatic events included sustained domestic violence (n = 6), abuse (n = 2), sexual or power harassment (n = 2), sexual or nonsexual crime (n = 2) in the clinical subsample; bullying (n = 3), injury (n = 3), unnatural death of close person or close place (n = 3), painful childhood incidents (divorce, punishment) in the family (n = 2), victim of stalker, molester, or encounter with a stranger with a weapon (n = 3), other setbacks (n = 2), or no answer/unclear (n = 2) in the non-clinical subsample. Most of the non-clinical participants (87%) answered that they experienced the index trauma over a half year ago, but data for the clinical sample was not clear.

Table 3. Discriminative values (95% CI), symptom severity correlation coefficients (Pearson’s r), and reliability coefficients (Cronbach’s alpha) of different candidates of the PDS 2- or 3-item scale applied to Japanese participants with and without PTSD.

Short versions of the PDS (DSM-IV Criteria)	Cut-point	SN	(95% CI)	SP	(95% CI)	Efficiency	(95% CI)	AUC	(95% CI)	r	(95% CI)	alpha
Two-item version
(B1, B2)	1/2	94.8	(90.4–97.5)	86.1	(80.1–89.7)	91.1	(86–94.2)	0.94	(0.90–0.98)	.82	(76–86.2)	.82
(B1, B3)	1/2	90.7	(85.7–94.3)	83.3	(76.6–88.1)	87.6	(81.8–91.7)	0.91	(85.8–95.8)	.76	(68.5–81.5)	.80
(B1, B4)	2/3	88.7	(83.4–92.6)	80.6	(73.4–85.8)	85.2	(79.1–89.7)	0.90	(84.1–95.1)	.77	(69.8–82.4)	.90
(B1, B5)	1/2	97.9	(93.9–99.4)	76.4	(70.9–78.4)	88.8	(84.1–90.5)	0.93	(88.4–97.2)	.84	(78.4–87.6)	.86
(B2, B3)	0/1	94.8	(90.2–97.6)	81.9	(75.7–85.6)	89.3	(84.1–92.5)	0.92	(87.8–96.9)	.79	(72.8–84.2)	.73
(B2, B4)	2/3	86.6	(81.5–90.2)	87.5	(80.6–92.4)	87.0	(81.1–91.1)	0.93	(88.5–97.1)	.82	(75.9–86.1)	.79
(B2, B5)	1/2	91.8	(87.1–94.8)	88.9	(82.6–93.1)	90.5	(85.2–94.1)	0.94	(90.4–98)	.86	(81.6–89.5)	.82
(B3, B4)	1/2	95.9	(91.3–98.3)	76.4	(70.2–79.6)	87.6	(82.3–90.3)	0.89	(83.4–94.5)	.75	(67–80.6)	.81
(B3, B5)	1/2	93.8	(89.2–96.7)	86.1	(79.9–90)	90.5	(85.3–93.9)	0.91	(86.3–96.3)	.80	(73.7–84.8)	.82
(B4, B5)	3/4	79.4	(74.1–83)	88.9	(81.8–93.8)	83.4	(77.4–87.6)	0.91	(85.8–95.6)	.81	(74.6–85.3)	.91
Three-item version
(B1, B2, B3)	1/2	95.9	(91.4–98.3)	81.9	(76–85.2)	89.9	(84.9–92.7)	0.94	(89.4–97.9)	.82	(76–86.2)	.85
(B1, B2, B4)	3/4	89.7	(84.7–93.2)	86.1	(79.4–90.9)	88.2	(82.4–92.2)	0.93	(88.7–97.4)	.82	(76.5–86.5)	.89
(B1, B2, B5)	2/3	94.8	(90.4–97.5)	86.1	(80.1–89.7)	91.1	(86–94.2)	0.95	(91–98.5)	.86	(81.7–89.6)	.88
(B1, B3, B4)	2/3	93.8	(89–96.9)	79.2	(72.7–83.3)	87.6	(82–91.1)	0.91	(85.6–95.8)	.78	(71–83.1)	.89
(B1, B3, B5)	2/3	92.8	(88.0–96.0)	83.3	(76.8–87.7)	88.8	(83.2–92.4)	0.93	(88.5–97.4)	.82	(76.6–86.6)	.88
(B1, B4, B5)	4/5	84.5	(79.3–88.4)	86.1	(79–91.3)	85.2	(79.1–89.6)	0.92	(87.3–96.5)	.82	(76.2–86.3)	.92
(B2, B3, B4)	2/3	94.8	(90.3–97.6)	83.3	(77.2–87)	89.9	(84.7–93.1)	0.93	(87.9–97)	.81	(75.6–85.9)	.84
(B2, B3, B5)	1/2	95.9	(91.5–98.2)	84.7	(78.9–87.9)	91.1	(86.1–93.8)	0.93	(89.1–97.6)	.85	(79.8–88.5)	.85
(B2, B4, B5)	2/3	95.9	(91.4–98.3)	80.6	(74.5–83.8)	89.3	(84.2–92.1)	0.93	(89.4–97.5)	.85	(80–88.6)	.89
(B3, B4, B5)	3/4	86.6	(81.5–90.2)	87.5	(80.6–92.4)	87.0	(81.1–91.1)	0.91	(86.2–96.1)	.80	(74.4–85.2)	.89

Bold numbers indicate values of the best candidate for the 2- or 3-item scale. PDS, Posttraumatic Diagnostic Scale; PTSD, posttraumatic stress disorder; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, 4th ed.; SN, sensitivity; SP, specificity; AUC, area under the curve.

Table 4. Diagnostic validity (AUC) and symptom severity correlation coefficients (Pearson’s r) for different candidate PDS 2- and 3-item scales applied to Japanese participants with and without PTSD, calculated separately with clinical, university, and female subsamples.

	Clinical subsample (n = 106)		University subsample (n = 63)		Female subsample (n = 137)
Short versions of the PDS (DSM-IV Criteria)	AUC	r	AUC	r	AUC	r
Two-item version
(B1, B2)	0.80	.58	0.91	.27	0.91	.76
(B1, B3)	0.70	.46	0.92	.29	0.92	.67
(B1, B4)	0.66	.43	0.89	.25	0.89	.70
(B1, B5)	0.69	.53	0.91	.41	0.91	.78
(B2, B3)	0.79	.59	0.81	.27	0.81	.72
(B2, B4)	0.79	.57	0.88	.26	0.88	.76
(B2, B5)*	0.79	.64	0.79	.46	0.79	.81
(B3, B4)	0.62	.41	0.88	.27	0.88	.66
(B3, B5)	0.64	.50	0.79	.44	0.79	.72
(B4, B5)	0.63	.46	0.88	.39	0.88	.73
Three-item version
(B1, B2, B3)	0.79	.59	0.93	.29	0.90	.75
(B1, B2, B4)	0.76	.56	0.90	.26	0.89	.76
(B1, B2, B5)*	0.78	.63	0.91	.40	0.91	.81
(B1, B3, B4)	0.67	.46	0.90	.28	0.85	.70
(B1, B3, B5)	0.70	.53	0.91	.40	0.88	.75
(B1, B4, B5)	0.68	.50	0.90	.35	0.87	.75
(B2, B3, B4)	0.74	.57	0.89	.28	0.88	.75
(B2, B3, B5)	0.75	.63	0.79	.40	0.89	.79
(B2, B4, B5)	0.75	.59	0.88	.38	0.89	.79
(B3, B4, B5)	0.64	.48	0.88	.38	0.85	.73

* indicate values of the best candidate for the 2- or 3-item scale in the whole sample analysis. Bold numbers indicate the best candidates in the sub-sample analysis. AUC, area under the curve.

Figure 1. Receiver operating characteristic (ROC) curve depicting the sensitivity and specificity of the brief version of the PDS in identifying individuals with PTSD, as determined through the CAPS (DSM-IV) interview. Area under the curve (AUC) was .95 (3-item version) and .94 (2-item version). PDS, Posttraumatic Diagnostic Scale; PTSD, posttraumatic stress disorder; CAPS, Clinician-Administered PTSD Scale; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, 4th ed.