Trust and group psychotherapy with veterans Williams et al.
Group psychotherapy’s impact on trust in veterans with PTSD: A pilot study Wright Williams, PhD David P. Graham, MD Katherine McCurry, BA April Sanders, PhD Jessica Eiseman, MA Pearl H. Chiu, PhD Brooks King-Casas, PhD
Wright Williams and David P. Graham are at the Mental Health Care Line, Michael E. DeBakey Department of Veterans Affairs Medical Center, Houston, Texas; and at South Central Mental Illness, Research, Education and Clinical Center, Houston, Texas. Wright Williams, David P. Graham, and Jessica Eiseman are at the Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas. David P. Graham is also at Neurorehabilitation: Neurons to Networks Traumatic Brain Injury Center of Excellence, Michael E. DeBakey Department of Veterans Affairs Medical Center, Houston, Texas. Katherine McCurry, Pearl H. Chiu, and Brooks King-Casas are at the Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia; and the Department of Psychology, Virginia Tech, Blacksburg, Virginia. Pearl H. Chiu and Brooks King-Casas are also at the Salem Veterans Affairs Medical Center, Salem, Virginia; and at the Department of Psychiatry, Virginia Tech Carilion School of Medicine, Roanoke, Virginia. April Sanders is at the Harris County Mental Health and Mental Retardation Authority (MHMRA), Houston, Texas. Both Brooks King-Casas, PhD, and Pearl Chiu, PhD, served as senior authors of this article. They were both project conceptualizers, oversaw data collection of the trust game, and edited the article, and the study was derived from their laboratory. The views expressed in this article are those of the authors and do not necessarily reflect the views, position, or policy of the Department of Veterans Affairs, the Neurorehabilitation: Neurons to Networks TBI Center of Excellence, the South Central Mental Illness, Research, Education and Clinical Center, the United States government, the Virginia Tech Carilion Research Institute, or Baylor College of Medicine. We are grateful for the following research support: Williams, Grant B7760-P, from VA Rehabilitation Research and Development; King-Casas, Grant D7030R, from VA Rehabilitation Research and Development; and Chiu, MH087692, from the National Institutes of Mental Health. Portions of this article were previously presented as a poster session at the International Society for Traumatic Stress Studies, Baltimore, Maryland, November 2011. Correspondence may be sent to Wright Williams, PhD, PTSD Clinical Team, Michael E. DeBakey VAMC, 2002 Holcombe Blvd., Houston, TX 77030; e-mail: [email protected] (Copyright © 2014 The Menninger Foundation)
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Interpersonal trust is fundamental for the recovery of trauma survivors and the effectiveness of group psychotherapy. Yet there is limited research on the relationship between interpersonal trust and group psychotherapy. Twenty-one male Vietnam combat veterans with posttraumatic stress disorder (PTSD) (6 in a longterm process group [LTP], 10 in a short-term cognitive processing therapy group [CPT], and 5 treatment-as-usual controls) were evaluated before and after group psychotherapy using the Posttraumatic Stress Disorder Checklist–Military Version (PCL-M) and an in-vivo measure of interpersonal trust, the Iterated Trust Game. Three (14.3%) of the veterans were African American, 9 were Caucasian (42.9%), and 9 were Hispanic (42.9%); they averaged 61.9 years of age (SD = 1.8 years). Change in PCL-M scores differed by group (controls: –1.0 ± 3.7; CPT: –15.5 ± 6.8; LTP: –1.3 ± 12.2; p = .003). CPT group subjects improved more than controls (p < .001) and trended toward more improvement than the LTP group (p = .081). Members of the LTP group, compared to nonprocess group participants, showed greater initial (p = .042), and posttherapy trust (p = .003). Posttreatment, interpersonal trust was significantly higher in the LTP than the CPT group (p < .001). These results suggest that CPT treatment may be better than LTP treatment for improving PTSD symptoms, but LTP therapy may be better than CPT therapy for improving interpersonal trust in veterans with PTSD. They suggest important roles for both group treatments and point to the value of interpersonal trust in successful recovery from PTSD. (Bulletin of the Menninger Clinic, 78[4], 335–348)
Interpersonal trust is fundamental for the recovery of trauma survivors (Herman, 1992). Numerous authors document how exposure to trauma shakes a survivor’s sense of self, his or her basic needs for trust and safety, self-worth, intimacy, and closeness with other people, and the ability to function independently and control his or her emotions (Bahrey, McCallum, & Piper, 1991; Brende & Parson, 1985; Herman, 1992; McCann & Pearlman, 1990; Saunders & Edelson, 1999). Many of these authors (e.g., Bahery et al., 1991; Brende & Parson, 1985; Herman, 1992; McCann & Pearlman, 1990; Saunders & Edelson, 1999) also discuss the important role of interpersonal trust in successful group treatment for people with posttraumatic stress 336
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disorder (PTSD). Interpersonal trust underlies the effectiveness of group psychotherapy (Yalom & Leszcz, 2005) and should be a marker of therapeutic improvement and a successful group treatment. Surprisingly, the group psychotherapy research literature rarely discusses the importance of basic trust among group members. There are voluminous discussions of other important aspects of group psychotherapy, including group cohesiveness, therapeutic alliance, transference, insight, feedback, the corrective emotional experience, interpersonal learning, and therapist self-disclosure (Rutan, Stone, & Shay, 2007; Yalom & Leszcz, 2005), but there is little about interpersonal trust. Yet basic trust is fundamental to all of these aspects of therapy (Erickson, 1950). The absence of literature on the measurement and understanding of interpersonal trust is a notable gap in the research. Economists have used measures of trust in predicting economic and political phenomena and in studying “social capital” (Arrow, 1972; Fukuyama, 1995). They have also talked about the difficulty of measuring trust (Glaeser, Laibson, Scheinkman, & Soutter, 2000). Consequently, even though most group therapy experts agree that basic trust between patient and therapist, and between group members, is an essential part of psychotherapy, one possible reason for the dearth of research literature on interpersonal trust is that it is not easy to accurately measure interpersonal trust. Economists have also argued that for a construct that is so significant and ubiquitous, the survey research instruments designed to measure trust have poor validity (Putnam, 1995) and typically consist of self-report questions that Glaeser and colleagues (2000) described as being “vague, abstract and hard to interpret” (p. 812). However, it is not clear how well the economic literature on trust applies to group psychotherapy. People with PTSD frequently suffer from interpersonal difficulties that group psychotherapy is particularly well suited to treating. Novaco and Chemtob (2002) found that anger and aggression are strongly associated with PTSD, particularly combat-related PTSD. Veterans with PTSD display difficulties coping with stress, depression, and anxiety, as well as impairments in social functioning that present considerable barriers to psychosocial reintegration and recovery (Forbes, Creamer, HawVol. 78, No. 4 (Fall 2014)
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thorne, Allen, & McHugh, 2003; Forbes et al., 2005; Forbes et al., 2008). The difficulty that people with PTSD have trusting others and regulating their negative feelings is a significant aspect of treatment interventions that increasingly focus on difficulties in interpersonal functioning (Chemtob, Novaco, Hamada, & Gross, 1997; Erbes, Polusny, Macdermid, & Compton, 2008; Monson et al., 2008). The purpose of this pilot study was to improve our understanding of interpersonal trust in group psychotherapy by using a measure of interpersonal trust known as the investment ratio (IR), which is well known in the behavioral economics but not in the group psychotherapy literature. We assessed interpersonal trust by asking subjects to play a multiround iterated trust game before and after a period of group psychotherapy treatment (King-Casas et al., 2005). We hypothesized: (Ho1) Veterans in group therapy will show more pre-post therapy improvement in trust and PTSD symptoms than controls, (Ho2) veterans in long-term group therapy (who had known each other longer) will have higher initial levels of trust than those veterans beginning treatment or controls, but will require longer time periods to demonstrate changes in trust and PTSD symptoms, and (Ho3) pre-post therapy changes in PTSD symptoms and trust will vary by therapy modality. Methods Subjects We recruited male combat veterans at the Michael E. DeBakey VA Medical Center (MEDVAMC). Long-term group therapy (LTP) subjects included veterans who had more than 5 years of group psychotherapy treatment and were participating in an ongoing process group, while short-term therapy subjects included veterans participating in a 12-week cognitive processing group (CPT). We also recruited a group of age- and combatmatched controls receiving medication but not receiving psychotherapy. We excluded subjects who had (1) dementia or an active neurological disorder, (2) active drug or alcohol abuse, (3) claustrophobia, (4) history of head injuries resulting in loss
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of consciousness for more than 10 minutes, and (5) a concurrent diagnosis of schizophrenia, schizoaffective disorder, delusional disorder, or organic psychosis. All the subjects included in the study were between 59 and 65 years of age (M = 61.9 years, SD = 1.8) and had a diagnosis of PTSD as assessed by their MEDVAMC provider. All were referred for PTSD treatment by a MEDVAMC provider. The first author was the primary therapist for all the therapy groups. Long-term process group (LTP) The members of the long-term process group consisted of six veterans participating in weekly 90-minute sessions of psychodynamic psychotherapy emphasizing improving their relationships with other people and members of their family, learning how to cope and deal with their PTSD symptoms, and learning to regulate and contain their emotions. Short-term cognitive processing therapy group (CPT) This group consisted of 10 veterans participating in cognitive processing therapy (CPT). CPT is a 12-session empirically supported, manualized cognitive-behavioral therapy with elements of exposure treatment that helps participants learn to identify and restructure distorted beliefs that maintain PTSD. The targeted beliefs focus on those about safety, trust, emotional power and control, self-esteem, and intimacy. CPT has been shown to be effective in the treatment of male and female military veterans with PTSD and improves concomitant difficulties with depression, affect regulation, and social adjustment (Chard, Resick, Monson, & Kattar, 2009; Chard, Schumm, Owens, & Cottingham, 2010; Monson et al., 2006). Control subjects This group consisted of five veterans who were receiving medication, but were not currently participating in any psychotherapy treatment. Control subjects were matched to experimental subjects on age (within 5 years) (one-way ANOVA, F = 1.1, p > .05), exposure to combat, and combat era.
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Iterated Trust Game We measured interpersonal trust with the Iterated Trust Game, a multiround social exchange game in which two people may mutually benefit through the expression and repayment of trust (for complete details, see King-Casas et al., 2005). In each of 10 rounds, one player (“investor”) was endowed with 20 points. The investor could choose whether or not to send any portion of the 20 points to a second player (“trustee”). Any amount the investor chose to send was tripled by the experimenter before being received by the trustee. The trustee could then repay any portion of the tripled investment. Veterans were instructed that they would (1) be re-endowed with 20 points at the start of each of the 10 rounds, (2) remain in the investor role throughout the 10-round exchange, and (3) be paid based upon the number of points accumulated across the 10-round exchange. Veterans were also instructed that they would be playing either an anonymous human partner or a computer partner designed to play like a human. In fact, all veterans played a computer partner, thus standardizing trustee behavior across the veteran cohort. To the extent that the trust-repay cycle is successful, individuals cooperate with each other and achieve mutually higher point totals, and the trust-repay cycle continues. To the extent that trust is not repaid, cooperation breaks down and individuals cease to interact. Trust can be quantified as the monetary units sent and received. The value of the trust-repay cycle is that it evokes patterns of social interactions similar to those of many human interactions. The Trust Game has been utilized as a sensitive measure of cooperative exchange with both healthy populations (Delgado, Frank, & Phelps, 2005; King-Casas et al., 2005; McCabe, Houser, Ryan, Smith, & Trouard, 2001; Tomlin et al., 2006) and groups with social difficulties, including people with autism and borderline personality disorder (Chiu et al., 2008; King-Casas et al., 2008). In the present study, the average investment ratio (IR), or the fraction of points invested across the 10 rounds, was used to quantify a veteran’s behavioral level of trust. CPT and control group subjects completed the Iterated Trust Game before and after 12 weeks of treatment as usual or group CPT. Process group members completed these measures before and after a 25-week group segment. 340
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Posttraumatic Stress Disorder Checklist (PCL) The PTSD Checklist–Military version (PCL-M; Weathers, Litz, Herman, Huska, & Keane, 1993) is a 17-item self-report measure of the 17 DSM-IV PTSD symptoms. Subjects rated their PTSD symptoms on a 5-point Likert-type scale, based on how much they had been bothered by a particular symptom in the past week. The items are summed to create a total PCL score. The PCL has demonstrated good reliability and validity (Bliese et al., 2008; Lang, Laffaye, Satz, Dresselhaus, & Stein, 2003; Walker, Newman, Dobie, Ciechanowski, & Katon, 2002). CPT and control group subjects completed the PCL-M before and after 12 weeks of treatment as usual or group CPT. Process group members completed the PCL-M before and after a 25week group segment. Power analysis Our a priori power analysis was done with the expectation that this pilot study would enroll 6 control, 12 CPT, and 6 LTP group participants. PCL-M power was based on predeployment PCLM scores (Gewitz, Polusny, DeGarmo, Khaylis, & Erbes, 2010), with an 80% power, an alpha = .05, two-tailed; with at least six persons per group, we had the power to detect a total PCLM score difference of 16.1 points. We had no reference in the literature to base our IR predictions upon. Therefore, we calculated that with an 80% power, an alpha = .05, two-tailed, we would have the power to detect an average IR between group difference of 34.5%. Due to the low samples sizes available in this pilot study, we chose to not apply the Bonferroni correction and have retained our alpha = .05. We used DSS Research to calculate power and sample size requirements (http://www.dssresearch.com/KnowledgeCenter/ ToolkitCalculators.aspx). Statistical procedures We evaluated the demographic variables using an ANOVA for continuous variables and a nonparametric test as appropriate (chi-square, Wilcoxin rank sum) for categorical variables. We conducted three ANOVAs to evaluate pretherapy, posttherapy, Vol. 78, No. 4 (Fall 2014)
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and pre-post therapy change differences in trust (IR Score) and in PTSD (PCL-M scores) by group. The first ANOVA compared veterans in treatment (CPT and LTP) with the control group. The second ANOVA compared the LTP group with those groups who did not know each other well (CPT and controls). The third ANOVA evaluated the influence of treatment type by performing a three-way group comparison. We assessed the multiple comparisons using the Games-Howell procedure to account for differences in treatment group sample sizes and variances. Results Demographics The sample consisted of Vietnam combat veterans who averaged 61.9 years of age (SD = 1.8 years). It included: three (14.3%) African American, nine Caucasian (42.9%), and nine Hispanic (42.9%) men. Half (11, 52.4%) were married, two (9.5%) were single, six (28.6%) were remarried, and two (9.5%) were divorced. There were no differences in age, race, or marital status between the treatment and the control subjects, or subjects in LTP, CPT, and controls (all p > .05). Comparison of IR and PCL-M scores for controls versus treatment (Ho1) To evaluate Ho1 that veterans in group therapy treatment will show more improvement in trust compared to controls, we compared the mean pretherapy, posttherapy, and pre-post therapy change in PCL-M and IR scores for controls versus participants in treatment. Combining CPT and the process group subjects versus the controls resulted in no significant differences in PCLM or IR scores before or after treatment or in pre-post therapy changes, despite large posttreatment improvement in the process group IR scores. Comparison of IR and PCL-M scores for process versus nonprocess groups (Ho2) To evaluate Ho2 that veterans in the long-term process group therapy, who have known each other longer, would have higher 342
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Trust and group psychotherapy with veterans Table 1. Pretherapy, posttherapy, and pre-post therapy mean and standard deviation (± SD) PTSD Checklist–Military (PCL-M) and investment ratio (IR) scores by treatment group CPT & Control Group
Process Group
p value
Pretherapy PCL
60.67 (13.46)
58.17 (10.98)
.692
Posttherapy PCL
50.03 (13.89)
56.83 (13.38)
.319
Pre-Post PCL Change
10.63 (9.12)
−1.33 (12.21)
.070
Pretherapy IR
34.1% (21.2%)
59.1% (29.6%)
.042*
Posttherapy IR
39.9% (31.4%)
86.8% (16.8%)
.003**
Pre-Post IR Change
5.8% (23.7%)
27.8% (38.5%)
.126
Note. PCL: Posttraumatic Stress Symptom Checklist–Military. IR: Average Investment Ratio score from the Iterated Trust Game. *p ≤ .05, **p ≤ .01.
initial levels of trust than those veterans who did not know each other, we compared participants in the LTP group to participants in the control and CPT groups (Table 1). The process group did, compared to the nonprocess group participants, show greater initial (p = .042) and posttherapy (p = .003) trust. We found no differences in pre-post therapy changes in trust, pretherapy PCL-M scores, posttherapy PCL-M scores, or pre-post changes in PCL-M scores (all p > .05). Comparison of pre-post therapy changes by group (Ho3) To evaluate the influence of therapy on changes in trust and PTSD symptoms (Ho3), we compared the change in PCL-M scores between controls, CPT, and LTP group participants (Table 2). There was differential improvement in PCL-M scores by group (controls: –1.0 ± 3.7; CPT: –15.5 ± 6.8; Process: –1.3 ± 12.2; p = .003), with the CPT group showing more improvement than the controls (p < .001) and trending toward more improvement compared to the LTP group (p = .081). IR scores, however, went the other way. At posttherapy, IR scores were significantly higher in the LTP group than in the CPT group (p < .001). Discussion This study was designed to explore the impact of group psychotherapy on changes in interpersonal trust. We found that Vol. 78, No. 4 (Fall 2014)
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short-term group CPT therapy was superior to the control notherapy modality and tended to be superior to the LTP group in reducing PTSD symptoms. The fact that after many years of therapy the members of an LTP group did not have lower initial PTSD symptoms, as measured by PCL scores, could raise questions about the effectiveness of process group therapy in treating Vietnam veterans with PTSD. However, we also found that participation in the LTP group was associated with greater interpersonal trust—a valuable finding for veterans with PTSD, possibly linked to improvement in interpersonal and community functioning. Future work should address whether self-report measures of PTSD symptoms or behavioral measures of trust are more predictive of recovery from PTSD, or whether both are important aspects. Economic research (Arrow, 1972; Fukuyama, 1995; La Porta, Lopez-de-Silanes, Shleifer, & Vishny, 1997; Putnam, 1993) suggests that a society’s level of trust predicts its economic success, and notes that an increase in a country’s trust predicts an increase in its economic growth (Knack & Keefer, 1997). In this study, there is an analogy between a society’s level of trust at the economic level and the level of trust a group therapy participant was willing to invest in another person. These preliminary findings suggest that effective treatment for PTSD may improve both PTSD symptoms and interpersonal trust, and they provide support for the effectiveness of group psychotherapy in a heterogeneous veteran sample. The results generally suggest that CPT group therapy has the potential to reduce PTSD symptoms versus a treatment-as-usual control, and the long-term process group therapy has the potential to improve interpersonal trust. The results from the LTP group affirm the commonsense notion that trust develops in relationships over a long period of time. They also suggest that improvements in trust and in PTSD symptoms may not necessarily be directly related, and raise the possibility that long-term process groups may continue to offer treatment benefits by helping combat veterans with PTSD improve their interpersonal functioning. The current study also illustrates a potential methodological advancement in this area through the use of a behavioral 344
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Trust and group psychotherapy with veterans Table 2. Pretherapy, posttherapy, and pre-post therapy average (± SD) scores for PTSD symptom severity and trust by treatment: Control, CPT, or Process Comparisonsa
Control
CPT Group
Process Group
Pretherapy PCL
58.80 (12.38)
61.60 (14.52)
58.17 (10.98)
.859
ns
Posttherapy PCL
57.80 (13.59)
46.15 (12.95)
56.83 (13.38)
.184
ns
Pre-Post PCL Change
−1.00 (3.67)
−15.45 (6.78)
−1.33 (12.21)
.003
CPT > Controlb
Pretherapy IR
39.7% (31.6%)
31.3% (15.0%)
59.1% (29.6%)
.109
n.s.
Posttherapy IR
52.1% (42.7%)
33.9% (24.6%)
86.8% (16.8%)
.007
Process > CPT c
Pre-Post IR Change
12.4% (21.6%)
2.6% (25.0%)
27.8% (38.5%)
.264
ns
p value
Note. PCL: Posttraumatic Stress Symptom Checklist–Military, IR: Average Investment Ratio score from the Iterated Trust Game, ns = non-significant. aMultiple comparisons were performed using the Games-Howell procedure to account for differences in group sample sizes and group variances. b Pre-Post PCL change comparisons: Control versus CPT, p < .001; Control versus Process, p = .998; CPT versus Process, p = .081. cPost IR comparisons: Control versus CPT, p = .670; Control versus Process, p = .289; CPT versus Process, p < .001.
economic task to operationalize a construct typically assessed through self-report questionnaires. Tschuschke and Dies (1994) surveyed group psychotherapist investigators from 29 countries who reported that “our understanding of group process has been hampered … by the excessive reliance on patient selfreports” (p. 185). Our findings suggest not only the important role of interpersonal trust in treatment, but also the potential value of the Trust Game in future treatment research as a novel measure of interpersonal trust. This pilot study is limited by its small sample size, the fact that the first author served as the primary group therapist, the use of PCL-M instead of CAPS scores as a primary outcome measure, and longer Time 2 measures in the LTP. Nevertheless, these results offer suggestions for future research. First, we need larger sample sizes to distinguish between the impact of shortterm cognitive and longer-term process groups for the noted interactions in changes in trust and PTSD symptoms. Second, we need much more work into the mechanisms that result in changes in trust and improvements in PTSD symptoms in group Vol. 78, No. 4 (Fall 2014)
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psychotherapy. Was it the longer-term treatment, the type of treatment, the longer Time 2 time interval, or the tenacity of the LTP group members that led to increased trust? Which aspects of group treatment caused the PTSD symptom reductions in CPT participants? Finally, we remain curious about the role of changes in trust and PTSD symptom reduction in community reintegration and recovery. In conclusion, this pilot study’s results suggest that short-term PTSD-focused therapy may be better than long-term process therapy for improving PTSD symptoms in Vietnam veterans, but long-term process therapy may be better than short-term cognitive therapy at improving interpersonal trust in veterans with PTSD. References Arrow, K. (1972). Gifts and exchanges. Philosophy and Public Affairs, I, 343–362. Bahrey, F., McCallum, M., & Piper, W. E. (1991). Emergent themes and roles in short-term loss groups. International Journal of Group Psychotherapy, 41(3), 329–345. Bliese, P. D., Wright, K. M., Adler, A. B., Cabrera, O., Castro, C. A., & Hoge, C. W. (2008). Validating The Primary Care Posttraumatic Stress Disorder Screen and the Posttraumatic Stress Disorder Checklist with soldiers returning from combat. Journal of Consulting and Clinical Psychology, 76(2), 272–281. Brende, J. O., & Parson, E. R. (1985). Vietnam veterans: The road to recovery. New York, NY: Plenum Press. Chard, K. M., Resick, P. A., Monson, C. M., & Kattar, K. A. (2009). Cognitive processing therapy therapist group manual: Veteran/military version. Washington, DC: Department of Veterans Affairs. Chard, K. M., Schumm, J. A., Owens, G. P., & Cottingham, S. M. (2010). A comparison of OEF and OIF veterans and Vietnam veterans receiving cognitive processing therapy. Journal of Traumatic Stress, 23(1), 25–32. Chemtob, C. M., Novaco, R. W., Hamada, R. S., & Gross, D. M. (1997). Cognitive-behavioral treatment for severe anger in posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 65, 184–189. Chiu, P. H., Kayali, M. A., Kishida, K. T., Tomlin, D., Klinger, L. G., Klinger, M., & Montague, P. R. (2008). Active interpersonal exchange evokes quantitative neural phenotype in high-functioning autism. Neuron, 57, 463–473.
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Group psychotherapy’s impact on trust in veterans with PTSD: A pilot study Wright Williams, PhD David P. Graham, MD Katherine McCurry, BA April Sanders, PhD Jessica Eiseman, MA Pearl H. Chiu, PhD Brooks King-Casas, PhD
Wright Williams and David P. Graham are at the Mental Health Care Line, Michael E. DeBakey Department of Veterans Affairs Medical Center, Houston, Texas; and at South Central Mental Illness, Research, Education and Clinical Center, Houston, Texas. Wright Williams, David P. Graham, and Jessica Eiseman are at the Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, Texas. David P. Graham is also at Neurorehabilitation: Neurons to Networks Traumatic Brain Injury Center of Excellence, Michael E. DeBakey Department of Veterans Affairs Medical Center, Houston, Texas. Katherine McCurry, Pearl H. Chiu, and Brooks King-Casas are at the Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia; and the Department of Psychology, Virginia Tech, Blacksburg, Virginia. Pearl H. Chiu and Brooks King-Casas are also at the Salem Veterans Affairs Medical Center, Salem, Virginia; and at the Department of Psychiatry, Virginia Tech Carilion School of Medicine, Roanoke, Virginia. April Sanders is at the Harris County Mental Health and Mental Retardation Authority (MHMRA), Houston, Texas. Both Brooks King-Casas, PhD, and Pearl Chiu, PhD, served as senior authors of this article. They were both project conceptualizers, oversaw data collection of the trust game, and edited the article, and the study was derived from their laboratory. The views expressed in this article are those of the authors and do not necessarily reflect the views, position, or policy of the Department of Veterans Affairs, the Neurorehabilitation: Neurons to Networks TBI Center of Excellence, the South Central Mental Illness, Research, Education and Clinical Center, the United States government, the Virginia Tech Carilion Research Institute, or Baylor College of Medicine. We are grateful for the following research support: Williams, Grant B7760-P, from VA Rehabilitation Research and Development; King-Casas, Grant D7030R, from VA Rehabilitation Research and Development; and Chiu, MH087692, from the National Institutes of Mental Health. Portions of this article were previously presented as a poster session at the International Society for Traumatic Stress Studies, Baltimore, Maryland, November 2011. Correspondence may be sent to Wright Williams, PhD, PTSD Clinical Team, Michael E. DeBakey VAMC, 2002 Holcombe Blvd., Houston, TX 77030; e-mail: [email protected] (Copyright © 2014 The Menninger Foundation)
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Interpersonal trust is fundamental for the recovery of trauma survivors and the effectiveness of group psychotherapy. Yet there is limited research on the relationship between interpersonal trust and group psychotherapy. Twenty-one male Vietnam combat veterans with posttraumatic stress disorder (PTSD) (6 in a longterm process group [LTP], 10 in a short-term cognitive processing therapy group [CPT], and 5 treatment-as-usual controls) were evaluated before and after group psychotherapy using the Posttraumatic Stress Disorder Checklist–Military Version (PCL-M) and an in-vivo measure of interpersonal trust, the Iterated Trust Game. Three (14.3%) of the veterans were African American, 9 were Caucasian (42.9%), and 9 were Hispanic (42.9%); they averaged 61.9 years of age (SD = 1.8 years). Change in PCL-M scores differed by group (controls: –1.0 ± 3.7; CPT: –15.5 ± 6.8; LTP: –1.3 ± 12.2; p = .003). CPT group subjects improved more than controls (p < .001) and trended toward more improvement than the LTP group (p = .081). Members of the LTP group, compared to nonprocess group participants, showed greater initial (p = .042), and posttherapy trust (p = .003). Posttreatment, interpersonal trust was significantly higher in the LTP than the CPT group (p < .001). These results suggest that CPT treatment may be better than LTP treatment for improving PTSD symptoms, but LTP therapy may be better than CPT therapy for improving interpersonal trust in veterans with PTSD. They suggest important roles for both group treatments and point to the value of interpersonal trust in successful recovery from PTSD. (Bulletin of the Menninger Clinic, 78[4], 335–348)
Interpersonal trust is fundamental for the recovery of trauma survivors (Herman, 1992). Numerous authors document how exposure to trauma shakes a survivor’s sense of self, his or her basic needs for trust and safety, self-worth, intimacy, and closeness with other people, and the ability to function independently and control his or her emotions (Bahrey, McCallum, & Piper, 1991; Brende & Parson, 1985; Herman, 1992; McCann & Pearlman, 1990; Saunders & Edelson, 1999). Many of these authors (e.g., Bahery et al., 1991; Brende & Parson, 1985; Herman, 1992; McCann & Pearlman, 1990; Saunders & Edelson, 1999) also discuss the important role of interpersonal trust in successful group treatment for people with posttraumatic stress 336
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disorder (PTSD). Interpersonal trust underlies the effectiveness of group psychotherapy (Yalom & Leszcz, 2005) and should be a marker of therapeutic improvement and a successful group treatment. Surprisingly, the group psychotherapy research literature rarely discusses the importance of basic trust among group members. There are voluminous discussions of other important aspects of group psychotherapy, including group cohesiveness, therapeutic alliance, transference, insight, feedback, the corrective emotional experience, interpersonal learning, and therapist self-disclosure (Rutan, Stone, & Shay, 2007; Yalom & Leszcz, 2005), but there is little about interpersonal trust. Yet basic trust is fundamental to all of these aspects of therapy (Erickson, 1950). The absence of literature on the measurement and understanding of interpersonal trust is a notable gap in the research. Economists have used measures of trust in predicting economic and political phenomena and in studying “social capital” (Arrow, 1972; Fukuyama, 1995). They have also talked about the difficulty of measuring trust (Glaeser, Laibson, Scheinkman, & Soutter, 2000). Consequently, even though most group therapy experts agree that basic trust between patient and therapist, and between group members, is an essential part of psychotherapy, one possible reason for the dearth of research literature on interpersonal trust is that it is not easy to accurately measure interpersonal trust. Economists have also argued that for a construct that is so significant and ubiquitous, the survey research instruments designed to measure trust have poor validity (Putnam, 1995) and typically consist of self-report questions that Glaeser and colleagues (2000) described as being “vague, abstract and hard to interpret” (p. 812). However, it is not clear how well the economic literature on trust applies to group psychotherapy. People with PTSD frequently suffer from interpersonal difficulties that group psychotherapy is particularly well suited to treating. Novaco and Chemtob (2002) found that anger and aggression are strongly associated with PTSD, particularly combat-related PTSD. Veterans with PTSD display difficulties coping with stress, depression, and anxiety, as well as impairments in social functioning that present considerable barriers to psychosocial reintegration and recovery (Forbes, Creamer, HawVol. 78, No. 4 (Fall 2014)
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thorne, Allen, & McHugh, 2003; Forbes et al., 2005; Forbes et al., 2008). The difficulty that people with PTSD have trusting others and regulating their negative feelings is a significant aspect of treatment interventions that increasingly focus on difficulties in interpersonal functioning (Chemtob, Novaco, Hamada, & Gross, 1997; Erbes, Polusny, Macdermid, & Compton, 2008; Monson et al., 2008). The purpose of this pilot study was to improve our understanding of interpersonal trust in group psychotherapy by using a measure of interpersonal trust known as the investment ratio (IR), which is well known in the behavioral economics but not in the group psychotherapy literature. We assessed interpersonal trust by asking subjects to play a multiround iterated trust game before and after a period of group psychotherapy treatment (King-Casas et al., 2005). We hypothesized: (Ho1) Veterans in group therapy will show more pre-post therapy improvement in trust and PTSD symptoms than controls, (Ho2) veterans in long-term group therapy (who had known each other longer) will have higher initial levels of trust than those veterans beginning treatment or controls, but will require longer time periods to demonstrate changes in trust and PTSD symptoms, and (Ho3) pre-post therapy changes in PTSD symptoms and trust will vary by therapy modality. Methods Subjects We recruited male combat veterans at the Michael E. DeBakey VA Medical Center (MEDVAMC). Long-term group therapy (LTP) subjects included veterans who had more than 5 years of group psychotherapy treatment and were participating in an ongoing process group, while short-term therapy subjects included veterans participating in a 12-week cognitive processing group (CPT). We also recruited a group of age- and combatmatched controls receiving medication but not receiving psychotherapy. We excluded subjects who had (1) dementia or an active neurological disorder, (2) active drug or alcohol abuse, (3) claustrophobia, (4) history of head injuries resulting in loss
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of consciousness for more than 10 minutes, and (5) a concurrent diagnosis of schizophrenia, schizoaffective disorder, delusional disorder, or organic psychosis. All the subjects included in the study were between 59 and 65 years of age (M = 61.9 years, SD = 1.8) and had a diagnosis of PTSD as assessed by their MEDVAMC provider. All were referred for PTSD treatment by a MEDVAMC provider. The first author was the primary therapist for all the therapy groups. Long-term process group (LTP) The members of the long-term process group consisted of six veterans participating in weekly 90-minute sessions of psychodynamic psychotherapy emphasizing improving their relationships with other people and members of their family, learning how to cope and deal with their PTSD symptoms, and learning to regulate and contain their emotions. Short-term cognitive processing therapy group (CPT) This group consisted of 10 veterans participating in cognitive processing therapy (CPT). CPT is a 12-session empirically supported, manualized cognitive-behavioral therapy with elements of exposure treatment that helps participants learn to identify and restructure distorted beliefs that maintain PTSD. The targeted beliefs focus on those about safety, trust, emotional power and control, self-esteem, and intimacy. CPT has been shown to be effective in the treatment of male and female military veterans with PTSD and improves concomitant difficulties with depression, affect regulation, and social adjustment (Chard, Resick, Monson, & Kattar, 2009; Chard, Schumm, Owens, & Cottingham, 2010; Monson et al., 2006). Control subjects This group consisted of five veterans who were receiving medication, but were not currently participating in any psychotherapy treatment. Control subjects were matched to experimental subjects on age (within 5 years) (one-way ANOVA, F = 1.1, p > .05), exposure to combat, and combat era.
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Iterated Trust Game We measured interpersonal trust with the Iterated Trust Game, a multiround social exchange game in which two people may mutually benefit through the expression and repayment of trust (for complete details, see King-Casas et al., 2005). In each of 10 rounds, one player (“investor”) was endowed with 20 points. The investor could choose whether or not to send any portion of the 20 points to a second player (“trustee”). Any amount the investor chose to send was tripled by the experimenter before being received by the trustee. The trustee could then repay any portion of the tripled investment. Veterans were instructed that they would (1) be re-endowed with 20 points at the start of each of the 10 rounds, (2) remain in the investor role throughout the 10-round exchange, and (3) be paid based upon the number of points accumulated across the 10-round exchange. Veterans were also instructed that they would be playing either an anonymous human partner or a computer partner designed to play like a human. In fact, all veterans played a computer partner, thus standardizing trustee behavior across the veteran cohort. To the extent that the trust-repay cycle is successful, individuals cooperate with each other and achieve mutually higher point totals, and the trust-repay cycle continues. To the extent that trust is not repaid, cooperation breaks down and individuals cease to interact. Trust can be quantified as the monetary units sent and received. The value of the trust-repay cycle is that it evokes patterns of social interactions similar to those of many human interactions. The Trust Game has been utilized as a sensitive measure of cooperative exchange with both healthy populations (Delgado, Frank, & Phelps, 2005; King-Casas et al., 2005; McCabe, Houser, Ryan, Smith, & Trouard, 2001; Tomlin et al., 2006) and groups with social difficulties, including people with autism and borderline personality disorder (Chiu et al., 2008; King-Casas et al., 2008). In the present study, the average investment ratio (IR), or the fraction of points invested across the 10 rounds, was used to quantify a veteran’s behavioral level of trust. CPT and control group subjects completed the Iterated Trust Game before and after 12 weeks of treatment as usual or group CPT. Process group members completed these measures before and after a 25-week group segment. 340
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Posttraumatic Stress Disorder Checklist (PCL) The PTSD Checklist–Military version (PCL-M; Weathers, Litz, Herman, Huska, & Keane, 1993) is a 17-item self-report measure of the 17 DSM-IV PTSD symptoms. Subjects rated their PTSD symptoms on a 5-point Likert-type scale, based on how much they had been bothered by a particular symptom in the past week. The items are summed to create a total PCL score. The PCL has demonstrated good reliability and validity (Bliese et al., 2008; Lang, Laffaye, Satz, Dresselhaus, & Stein, 2003; Walker, Newman, Dobie, Ciechanowski, & Katon, 2002). CPT and control group subjects completed the PCL-M before and after 12 weeks of treatment as usual or group CPT. Process group members completed the PCL-M before and after a 25week group segment. Power analysis Our a priori power analysis was done with the expectation that this pilot study would enroll 6 control, 12 CPT, and 6 LTP group participants. PCL-M power was based on predeployment PCLM scores (Gewitz, Polusny, DeGarmo, Khaylis, & Erbes, 2010), with an 80% power, an alpha = .05, two-tailed; with at least six persons per group, we had the power to detect a total PCLM score difference of 16.1 points. We had no reference in the literature to base our IR predictions upon. Therefore, we calculated that with an 80% power, an alpha = .05, two-tailed, we would have the power to detect an average IR between group difference of 34.5%. Due to the low samples sizes available in this pilot study, we chose to not apply the Bonferroni correction and have retained our alpha = .05. We used DSS Research to calculate power and sample size requirements (http://www.dssresearch.com/KnowledgeCenter/ ToolkitCalculators.aspx). Statistical procedures We evaluated the demographic variables using an ANOVA for continuous variables and a nonparametric test as appropriate (chi-square, Wilcoxin rank sum) for categorical variables. We conducted three ANOVAs to evaluate pretherapy, posttherapy, Vol. 78, No. 4 (Fall 2014)
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and pre-post therapy change differences in trust (IR Score) and in PTSD (PCL-M scores) by group. The first ANOVA compared veterans in treatment (CPT and LTP) with the control group. The second ANOVA compared the LTP group with those groups who did not know each other well (CPT and controls). The third ANOVA evaluated the influence of treatment type by performing a three-way group comparison. We assessed the multiple comparisons using the Games-Howell procedure to account for differences in treatment group sample sizes and variances. Results Demographics The sample consisted of Vietnam combat veterans who averaged 61.9 years of age (SD = 1.8 years). It included: three (14.3%) African American, nine Caucasian (42.9%), and nine Hispanic (42.9%) men. Half (11, 52.4%) were married, two (9.5%) were single, six (28.6%) were remarried, and two (9.5%) were divorced. There were no differences in age, race, or marital status between the treatment and the control subjects, or subjects in LTP, CPT, and controls (all p > .05). Comparison of IR and PCL-M scores for controls versus treatment (Ho1) To evaluate Ho1 that veterans in group therapy treatment will show more improvement in trust compared to controls, we compared the mean pretherapy, posttherapy, and pre-post therapy change in PCL-M and IR scores for controls versus participants in treatment. Combining CPT and the process group subjects versus the controls resulted in no significant differences in PCLM or IR scores before or after treatment or in pre-post therapy changes, despite large posttreatment improvement in the process group IR scores. Comparison of IR and PCL-M scores for process versus nonprocess groups (Ho2) To evaluate Ho2 that veterans in the long-term process group therapy, who have known each other longer, would have higher 342
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Trust and group psychotherapy with veterans Table 1. Pretherapy, posttherapy, and pre-post therapy mean and standard deviation (± SD) PTSD Checklist–Military (PCL-M) and investment ratio (IR) scores by treatment group CPT & Control Group
Process Group
p value
Pretherapy PCL
60.67 (13.46)
58.17 (10.98)
.692
Posttherapy PCL
50.03 (13.89)
56.83 (13.38)
.319
Pre-Post PCL Change
10.63 (9.12)
−1.33 (12.21)
.070
Pretherapy IR
34.1% (21.2%)
59.1% (29.6%)
.042*
Posttherapy IR
39.9% (31.4%)
86.8% (16.8%)
.003**
Pre-Post IR Change
5.8% (23.7%)
27.8% (38.5%)
.126
Note. PCL: Posttraumatic Stress Symptom Checklist–Military. IR: Average Investment Ratio score from the Iterated Trust Game. *p ≤ .05, **p ≤ .01.
initial levels of trust than those veterans who did not know each other, we compared participants in the LTP group to participants in the control and CPT groups (Table 1). The process group did, compared to the nonprocess group participants, show greater initial (p = .042) and posttherapy (p = .003) trust. We found no differences in pre-post therapy changes in trust, pretherapy PCL-M scores, posttherapy PCL-M scores, or pre-post changes in PCL-M scores (all p > .05). Comparison of pre-post therapy changes by group (Ho3) To evaluate the influence of therapy on changes in trust and PTSD symptoms (Ho3), we compared the change in PCL-M scores between controls, CPT, and LTP group participants (Table 2). There was differential improvement in PCL-M scores by group (controls: –1.0 ± 3.7; CPT: –15.5 ± 6.8; Process: –1.3 ± 12.2; p = .003), with the CPT group showing more improvement than the controls (p < .001) and trending toward more improvement compared to the LTP group (p = .081). IR scores, however, went the other way. At posttherapy, IR scores were significantly higher in the LTP group than in the CPT group (p < .001). Discussion This study was designed to explore the impact of group psychotherapy on changes in interpersonal trust. We found that Vol. 78, No. 4 (Fall 2014)
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short-term group CPT therapy was superior to the control notherapy modality and tended to be superior to the LTP group in reducing PTSD symptoms. The fact that after many years of therapy the members of an LTP group did not have lower initial PTSD symptoms, as measured by PCL scores, could raise questions about the effectiveness of process group therapy in treating Vietnam veterans with PTSD. However, we also found that participation in the LTP group was associated with greater interpersonal trust—a valuable finding for veterans with PTSD, possibly linked to improvement in interpersonal and community functioning. Future work should address whether self-report measures of PTSD symptoms or behavioral measures of trust are more predictive of recovery from PTSD, or whether both are important aspects. Economic research (Arrow, 1972; Fukuyama, 1995; La Porta, Lopez-de-Silanes, Shleifer, & Vishny, 1997; Putnam, 1993) suggests that a society’s level of trust predicts its economic success, and notes that an increase in a country’s trust predicts an increase in its economic growth (Knack & Keefer, 1997). In this study, there is an analogy between a society’s level of trust at the economic level and the level of trust a group therapy participant was willing to invest in another person. These preliminary findings suggest that effective treatment for PTSD may improve both PTSD symptoms and interpersonal trust, and they provide support for the effectiveness of group psychotherapy in a heterogeneous veteran sample. The results generally suggest that CPT group therapy has the potential to reduce PTSD symptoms versus a treatment-as-usual control, and the long-term process group therapy has the potential to improve interpersonal trust. The results from the LTP group affirm the commonsense notion that trust develops in relationships over a long period of time. They also suggest that improvements in trust and in PTSD symptoms may not necessarily be directly related, and raise the possibility that long-term process groups may continue to offer treatment benefits by helping combat veterans with PTSD improve their interpersonal functioning. The current study also illustrates a potential methodological advancement in this area through the use of a behavioral 344
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Trust and group psychotherapy with veterans Table 2. Pretherapy, posttherapy, and pre-post therapy average (± SD) scores for PTSD symptom severity and trust by treatment: Control, CPT, or Process Comparisonsa
Control
CPT Group
Process Group
Pretherapy PCL
58.80 (12.38)
61.60 (14.52)
58.17 (10.98)
.859
ns
Posttherapy PCL
57.80 (13.59)
46.15 (12.95)
56.83 (13.38)
.184
ns
Pre-Post PCL Change
−1.00 (3.67)
−15.45 (6.78)
−1.33 (12.21)
.003
CPT > Controlb
Pretherapy IR
39.7% (31.6%)
31.3% (15.0%)
59.1% (29.6%)
.109
n.s.
Posttherapy IR
52.1% (42.7%)
33.9% (24.6%)
86.8% (16.8%)
.007
Process > CPT c
Pre-Post IR Change
12.4% (21.6%)
2.6% (25.0%)
27.8% (38.5%)
.264
ns
p value
Note. PCL: Posttraumatic Stress Symptom Checklist–Military, IR: Average Investment Ratio score from the Iterated Trust Game, ns = non-significant. aMultiple comparisons were performed using the Games-Howell procedure to account for differences in group sample sizes and group variances. b Pre-Post PCL change comparisons: Control versus CPT, p < .001; Control versus Process, p = .998; CPT versus Process, p = .081. cPost IR comparisons: Control versus CPT, p = .670; Control versus Process, p = .289; CPT versus Process, p < .001.
economic task to operationalize a construct typically assessed through self-report questionnaires. Tschuschke and Dies (1994) surveyed group psychotherapist investigators from 29 countries who reported that “our understanding of group process has been hampered … by the excessive reliance on patient selfreports” (p. 185). Our findings suggest not only the important role of interpersonal trust in treatment, but also the potential value of the Trust Game in future treatment research as a novel measure of interpersonal trust. This pilot study is limited by its small sample size, the fact that the first author served as the primary group therapist, the use of PCL-M instead of CAPS scores as a primary outcome measure, and longer Time 2 measures in the LTP. Nevertheless, these results offer suggestions for future research. First, we need larger sample sizes to distinguish between the impact of shortterm cognitive and longer-term process groups for the noted interactions in changes in trust and PTSD symptoms. Second, we need much more work into the mechanisms that result in changes in trust and improvements in PTSD symptoms in group Vol. 78, No. 4 (Fall 2014)
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psychotherapy. Was it the longer-term treatment, the type of treatment, the longer Time 2 time interval, or the tenacity of the LTP group members that led to increased trust? Which aspects of group treatment caused the PTSD symptom reductions in CPT participants? Finally, we remain curious about the role of changes in trust and PTSD symptom reduction in community reintegration and recovery. In conclusion, this pilot study’s results suggest that short-term PTSD-focused therapy may be better than long-term process therapy for improving PTSD symptoms in Vietnam veterans, but long-term process therapy may be better than short-term cognitive therapy at improving interpersonal trust in veterans with PTSD. References Arrow, K. (1972). Gifts and exchanges. Philosophy and Public Affairs, I, 343–362. Bahrey, F., McCallum, M., & Piper, W. E. (1991). Emergent themes and roles in short-term loss groups. International Journal of Group Psychotherapy, 41(3), 329–345. Bliese, P. D., Wright, K. M., Adler, A. B., Cabrera, O., Castro, C. A., & Hoge, C. W. (2008). Validating The Primary Care Posttraumatic Stress Disorder Screen and the Posttraumatic Stress Disorder Checklist with soldiers returning from combat. Journal of Consulting and Clinical Psychology, 76(2), 272–281. Brende, J. O., & Parson, E. R. (1985). Vietnam veterans: The road to recovery. New York, NY: Plenum Press. Chard, K. M., Resick, P. A., Monson, C. M., & Kattar, K. A. (2009). Cognitive processing therapy therapist group manual: Veteran/military version. Washington, DC: Department of Veterans Affairs. Chard, K. M., Schumm, J. A., Owens, G. P., & Cottingham, S. M. (2010). A comparison of OEF and OIF veterans and Vietnam veterans receiving cognitive processing therapy. Journal of Traumatic Stress, 23(1), 25–32. Chemtob, C. M., Novaco, R. W., Hamada, R. S., & Gross, D. M. (1997). Cognitive-behavioral treatment for severe anger in posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 65, 184–189. Chiu, P. H., Kayali, M. A., Kishida, K. T., Tomlin, D., Klinger, L. G., Klinger, M., & Montague, P. R. (2008). Active interpersonal exchange evokes quantitative neural phenotype in high-functioning autism. Neuron, 57, 463–473.
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Copyright of Bulletin of the Menninger Clinic is the property of Guilford Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
