Interpersonal Psychotherapy for Posttraumatic Stress Disorder

Assessment
Baseline
Week 14
Change
Mean
SD of Mean 
Change
Effect
Size
a
p
b
Mean SD
Mean SD
CAPS- 2  (
n
 = 15)
66.3
16.0 23.5
16.1 42.8
23.6
1.8
.001
PSS- SR
 (
n
 = 16)
Total Score
69.4
21.5 20.3
14.2 49.1
22.6
2.2
.000
Re- experiencing 20.2
6.9
6.8
5.3 13.4
7.6
1.8
.001
Avoidance
28.8
9.8
6.5
6.7 22.3
11.4
2.0
.001
Hyperarousal
21.0
7.5
7.0
5.8 13.9
7.8
1.8
.000
Ham- D  (
n
 = 16)
17.8
8.0
8.8
5.9
9.0
7.0
1.3
.002
BDI (
n
 = 14)
16.9
8.9
6.1
6.8 10.9
9.4
1.2
.003
STAXI
State (
n
 = 15)
14.5
5.9 10.5
0.99 4.0
5.5
0.73
.005
Trait (
n
 = 13)
18.5
5.0 15.3
2.9
3.1
4.4
0.70
.025
SAS- SR  (
n
 = 13)
2.5
0.42 1.9
0.37 0.52
0.40
1.3
.003
CAPS- 2 = Clinician- Administered PTSD Scale, version 2; PSS- SR = Posttraumatic 
Stress Scale– Self Report Version; Ham- D = 24- item Hamilton Depression Rating Scale; 
BDI = Beck Depression Inventory; STAXI = State- Trait Anger Experience Inventory; 
SAS- SR = Social Adjustment Scale– Self Report version.
a
 Within- group effect size (Cohen’s d)
b
 Wilcoxon paired- rank sum tests

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10 
I P T   F O R   P T S D
to normative scores, interpersonal function on the IIP for PTSD subjects at 
baseline was worse than that of 82% of the population; after treatment, it ap-
proached the norm (54%) (Markowitz et al., 2006).
Six subjects assessed at six- month follow- up showed persisting remission, 
defined by a CAPS score of less than 20 (Davidson et al., p. 191). Mean CAPS 
score at follow- up was 16.8 (SD  =  9.6), compared to 14.2 (9.8) at week 14;  
Posttraumatic Stress Scale– Self Report (PSS- SR, a PTSD self- report scale) 
mean was 20.9 (26.9) at six months, versus 12.0 (6.8) at 14 weeks.
Summary:
 These very encouraging findings have their limits:  as noted, 
an open trial can provide encouragement for treatment development, but it 
cannot prove efficacy. Efficacy requires a randomized controlled trial. This 
study, however, provided the groundwork for such a trial.