Treatment of PTSD:
Stress Inoculation Training with Prolonged Exposure compared to EMDR

This is a preprint of: Lee, C., Gavriel, H., Drummond, P., Richards, J., & Greenwald, R. (2002). Treatment of PTSD: Stress Inoculation Training with Prolonged Exposure compared to EMDR. Journal of Clinical Psychology, 58, 1071-1089.

Address for correspondence is

Christopher Lee

88 Palmerston St

Mosman Park, WA

Australia 6012

Phone number: 61-893849617

Fax number: 61-892846010

Email address: chlee@central.murdoch.edu.au

Abstract

The effectiveness of Stress Inoculation Training with Prolonged Exposure (SITPE) was compared to Eye Movement Desensitisation and Reprocessing (EMDR). Twenty four participants who had a diagnosis of Post Traumatic Stress Disorder (PTSD) were randomly assigned to one of the treatment conditions. Participants were also their own wait list control. Outcome measures included self-report and observer-rated measures of PTSD, and self-report measures of depression. On global PTSD measures, there were no significant differences between the treatments at the end of therapy. However on the subscale measures of the degree of intrusion symptoms, EMDR did significantly better than SITPE. At follow-up EMDR was found to lead to greater gains on all measures.

The recent review commissioned by the APA task force on empirically validated psychological procedures stated that there are no well-established treatments for PTSD (Chambless et al., 1998). Nevertheless, this review found that three methods were "probably efficacious" for civilian populations, these being Exposure, Stress-inoculation, and EMDR.

Similarly in a recent meta-analysis of PTSD, Van Etten and Taylor (1998) concluded that EMDR and traditional behavior therapy (including exposure and cognitive interventions) were superior to all other psychological therapies immediately after treatment. They found that EMDR and traditional behavior therapy were equivalent in effect size to the most potent of the drug treatments which was found to be serotonin specific reuptake inhibitors (SSRI's). However the SSRI's had significantly higher drop-out rates than the psychological treatments. Unlike all other treatments, adequate follow up data was only available on the effectiveness of EMDR and traditional behaviour therapy. Both these therapies demonstrated maintenance of treatment effects at follow-up. Although generally equally effective, there were trends for some differences between Behavior Therapy and EMDR. Behavior Therapy was found to be more effective than EMDR on observer-rated total PTSD symptomatology at posttreatment but not on self-report measures. The apparent superiority of behavior therapy disappeared at follow-up with no differences between any of the total PTSD measures. Van Etten and Taylor (1998) also suggested that EMDR was more effective in reducing intrusion symptoms. Although Behavior Therapy and EMDR had comparable effect sizes for observer-rated intrusive symptoms, only EMDR was significantly more effective than all controls. A final observation was that although the effect sizes for EMDR and Behavior Therapy were equivalent, this treatment effect was achieved after an average of 4.6 sessions for EMDR compared to 14.8 sessions for Behavior Therapy.

The findings from this meta-analysis were congruent with the first study to directly compare EMDR with a behavioral procedure (Vaughan et al., 1994). Four sessions of EMDR were compared with imaginal exposure treatment and Applied Muscle Relaxation. There were significant improvements in all three treatment conditions compared with a waitlist control on both observer-rated symptomatology and self-report measures. There were few significant differences between the three treatments. An exception was the assessments by a blind independent observer which indicated that only participants treated with EMDR had more improvement in intrusive symptoms. However the small sample size in this study limited power in detecting significant differences between groups. Notably, equivalent treatment effects were reported even though EMDR involved less treatment time due to reduced homework requirements.

To assess the strengths and weaknesses of the Vaughan et al. (1994) study, we compared it against the standards proposed by Foa and Meadows (1997) for a methodologically sound outcome study in PTSD. These standards involve: clearly defined target symptoms, reliable and valid measures, use of blind evaluators, adequate assessor training, replicable/manualized treatments, unbiased assignment to treatment (which includes multiple therapists for each condition), and ratings of treatment adherence.

The Vaughan et al. (1994) study satisfied many of the criteria suggested by Foa and Meadows (1997). For example improvement was assessed using standardized measures of PTSD and other symptoms. A structured clinical interview was used to determine PTSD diagnostic status and the symptom severity of the population was clearly defined. The assessor was blind to treatment assignment. There was random assignment to all conditions and multiple therapists were used to deliver each of the treatments. The major problem with the study is that treatment integrity was unknown. There was no reference to detailed treatment manuals and there was no independent rater to assess the degree to which the treatments were conducted in the manner with which they were devised.

In a contrast to Vaughan et al. (1994), Devilly and Spence (1999) found EMDR to be less effective than an exposure based treatment both at the end of treatment and at three-month follow-up. The exposure based procedure (called TTP by the authors) combined Stress Inoculation Training and Prolonged Exposure. It was based on the work of Edna Foa and colleagues (Foa, Rothbaum, Riggs, and Murdock, 1991) but included additional cognitive components. Devilly and Spence stated that the subjects in the exposure based condition improved further during a three-month follow-up period while those in the EMDR condition returned to baseline. This result runs counter to the trend reported in the meta-analysis by Van Etten & Taylor (1998) of EMDR recipients improving further during follow-up.

The methodological rigour of the Devilly and Spence study was variable.

Assessing it against the Foa and Meadows standards, it is clear that Devilly and Spence defined the target symptoms in the population being treated, utilised valid and reliable measures, and used blind symptom evaluators at post treatment (but not at follow-up).

However the procedure of assigning participants to treatment has been criticised (Chemtob, Tolin, van der Kolk, & Pitman, 2000; Maxfield & Hyer, in press).

In addition the EMDR treatment delivered departed from the standard protocol in a number of ways (Maxfield & Hyer, in press ). These included rating the negative cognition, repeating the negative cognition during treatment, and omitting to target future and anticipated distressing material. The study also failed to meet the Foa et al. standard because multiple therapists were not used in both conditions making it difficult to separate treatment effects from therapist effects.

The primary purpose of the present study was to further investigate the relative effectiveness of the leading treatments for PTSD by comparing SITPE with EMDR. Particular attention was paid to treatment fidelity because comparative outcome studies to date have had weaknesses in this area. Furthermore, to more directly compare the efficiency of these two approaches, each participant was given the same number of treatment sessions and homework compliance was monitored. The effects of these treatments on global PTSD symptoms and intrusion symptoms were evaluated at post treatment and follow-up.

Method

All participants were referred for treatment of PTSD. Following initial assessment each participant was entered onto a wait list. After six weeks, participants whose diagnosis of PTSD was confirmed by structured interview were then randomly assigned to either SITPE or EMDR. Therapeutic outcome was assessed via self-report measures of PTSD that are free from experimenter bias, observer-rated measures of PTSD, and self-report measures of depression. These were collected immediately after treatment and at a three-month follow up.

Davidson’s Structured Interview for PTSD (SI-PTSD; Davidson, Smith, & Kudler, 1989). This required the clinician to assess the severity and frequency of particular symptoms associated with the diagnostic criteria for PTSD using DSM-III-R. Davidson et al. (1989) reported excellent diagnostic sensitivity and good specificity in comparison to other diagnostic interviews. Further construct validity was demonstrated by correlation analysis with the PTSD self-rating scale (Keane, Wolfe, & Taylor, 1987), the Hamilton Depression Scale (Hamilton, 1967), and the Hamilton Anxiety Scale (Hamilton, 1959). Although independent raters were initially used to score participant's responses this was not always possible and so most of these data were collected by the treating practitioner. Regular reviews every two weeks of these assessments of client symptoms were held to ensure consensus. These subjective measures were supplemented by a set of standardised objective measures.

Keane's Post-Traumatic Stress Disorder Scale from the Minnesota Multiphasic Personality Inventory (MMPI-K; Keane, Malloy, & Fairbank, 1984). This contains 49 MMPI items that have been shown to empirically differentiate between PTSD and non-PTSD veteran patients. According to Newman, Kaloupek, and Keane (1996), sensitivity and specificity varies from study to study but it appears to have moderate or strong psychometric qualities in most studies.

Impact of Event Scale (IES; Horowitz, Wilner, & Alvarez, 1979). This is one of the most widely used self-report measures of post-trauma symptomatology. The IES assesses the extent of avoidance, numbing and intrusion symptoms. Its advantages are that it has been widely used across a number of different trauma samples and that it is very easy to administer (Newman et al., 1996). However the measure does not assess hyper-arousal symptoms.

Beck Depression Inventory (BDI; Beck, Rush, Shaw, & Emery, 1979). This was included both as a measure of subjective distress to supplement scores on the IES and also because depression is thought to often accompany PTSD symptoms (Davidson & Foa, 1991).

All prospective participants were recruited either from the Clinical Psychology section of a large general hospital, the Psychology Department of a Government Defence service or a sexual assault referral centre. Practitioners were asked to refer people who appeared to have been traumatised by a recent event. All participants were interviewed about the nature of the trauma to ensure that it satisfied category "A" for PTSD using DSM-IV criteria. They were then given the IES and the BDI. Forty participants were referred with a range of traumas including sexual and physical assault, severe motor vehicle accidents, combat experience, and witnessing a murder.

At initial interview four people who met the criteria for Alcohol and Drug Dependency, Psychosis or a cluster B Personality Disorder as defined by DSM-IV (as assessed by the interviewing clinician) were excluded from the study. Another four people were excluded because of insufficient symptom severity (defined by a score of less than 32 on the IES) and one was excluded because of prior treatment with one of the procedures currently under investigation. Two failed to attend for reassessment.

The remaining 29 participants were re-interviewed after a 6 week wait list period. At this time all participants received the SI-PTSD and the MMPI-K. Two participants were excluded at this point because they failed to meet all of the diagnostic criteria for PTSD according to the SI-PTSD. The BDI and IES were then repeated.

Three participants dropped out of treatment: one from the SITPE condition, one from EMDR, and one went to prison. Thus 24 completed treatment, 12 were given EMDR, and 12 given SITPE.

The mean age of the 24 participants who completed the study was 35.3 years. There were 13 males and 11 females. Seventy five percent of the sample had less than 12 years of education, 62.5% had blue-collar occupations, but 62.5% were not currently employed. Roughly half of the participants (54.2%) were involved in litigation proceedings at the time of treatment. Most had significant trauma in the past, 70.8% had experienced a trauma prior to the current episode and 29.2% had experienced multiple previous traumas. In addition 58.3% rated their childhood origin as containing either physical abuse, emotional neglect, or sexual abuse. Many of the participants had a history of psychopathology. For example, 41.7% had received some form of psychological or psychiatric treatment in the past, 50% had family members who had received treatment from a mental health professional, and 20.8% had been hospitalized before with a psychiatric condition.

The same instruments administered at session 1 (SI-PTSD, MMPI-K, IES, BDI) were also administered posttreatment and at 3 month follow-up. The IES and BDI were also administered at the beginning of each session to assess intrusion, avoidance, and depression levels.

Participants were informed of the study at the pretreatment assessment and signed a consent form by the start of the first treatment session. Once each participant had been selected for the study he/she was assigned to one of the treatment conditions in alternate order, thus resulting in 12 participants for each treatment. Assignment of the first participant was via a coin toss. Each treatment program involved seven 90-minute sessions delivered on a weekly basis.

Three therapists were involved in treatment and each administered both treatments. Of the participants who completed treatment, 21 (11 SITPE, 10 EMDR) were treated by the first two authors who each had received Level I and Level II EMDR training by the EMDR Institute. Prior to EMDR training both therapists had considerable experience with exposure based strategies, had attended training workshops based on the Foa model and had given training workshops in this method. At about ¾ of the way through the study, one of the therapists also began offering training in EMDR. The third therapist was undergoing post-graduate psychology training. She treated three participants (1 SITPE, 2 EMDR) and received regular supervision from one of the primary therapists.

Independent treatment integrity checks were obtained from either video or audiotapes of the treatment sessions. A person not involved with this study randomly selected five tapes from each condition. Seven of these were videotapes.

The rater of the EMDR tapes was a clinical psychologist and an approved EMDR trainer by this Institute. The tapes were evaluated based on a checklist provided by the EMDR Institute. The checklist contained 27 items referring to aspects of the procedure. Each item was rated on a 1 to 7 scale according to its fidelity, where 1 = Poor and 7 = Excellent.

Rating the fidelity of the SITPE treatment was more difficult because there was no formal fidelity checklist to accompany the Foa manual. In addition there is no accreditation body for SITPE training. To improve the reliability of the assessment of SITPE fidelity, two raters assessed these sessions. They were asked to rate each tape on how well the procedures were employed, and the degree to which the therapist matched the instructions provided in the treatment manual. Fidelity was assessed on the same 1-7 scale used in the EMDR condition. Both raters were Clinical Psychologists with more than 10 years experience. Each had been trained at Universities that specialised in behavioral treatments. Both worked in accredited War Veteran programs and had attended workshops on SITPE methods. One rater trained staff in his unit and at universities in behavioral treatments for PTSD. Neither rater had EMDR training.

SITPE This treatment was based on a 22 page manual developed and supplied by Edna Foa. Foa et al (1991) stated that this combination of treatments was likely to be the most efficacious in treating PTSD. Each therapist maintained adherence to the treatment manual apart from adapting the client handouts and interventions from rape/sexual assault content to more general PTSD issues. Secondly the procedure was reduced from 9 sessions to 7 by excluding the session containing thought stopping and condensing the content of the first 3 sessions into 2 by providing the participants with more extensive homework exercises that included relaxation tapes and notes. Foa has also excluded the session containing thought stopping from a briefer version of her 9-session treatment (Foa et al., 1995).

The first session was devoted to assessment as well as briefly introducing the client to controlled breathing. This was an attempt to counter-condition any anxiety that may have evolved from discussion of the trauma. Session 2 began with an educational phase in which the treatment and rationale were described. A handout was introduced into this section to help explain how fear and anxiety become conditioned during traumatic events and how avoidance is often used as a coping mechanism. Trauma-related information was gathered in order to generate imaginal and in vivo exposures for treatment and homework. Brief training in progressive muscular relaxation was given and participants were then provided with the full version on a tape that they were required to use for daily practise in the next week.

Session 3 involved a prolonged exposure in which the participant was invited to recall a trauma memory. Participants were instructed to close their eyes and give a detailed present-tense account of this memory for more than an hour. If the narrative ended, the participant was asked to start at the beginning again. The therapist reinforced continued recall of the trauma material and discouraged avoidance behaviours. Anxiety levels were monitored every five minutes. The session was audiotaped and following exposure the client's reaction was discussed. The homework assignment was to listen daily for the next week to the taped scenario from the session.

Instruction on coping skills began in the fourth session. The format for teaching coping skills for sessions 4,5,6 and 7 was: definition of the coping skills; rationale and mechanism; demonstration; application 1 (practise with problem unrelated to trauma); review; and application 2 (practise on trauma-related problem). The skills training occupied the first 45 minutes of the session. The next 45 minutes consisted of imaginal exposure using the same format as that described in session 3. The homework assignment was to carry out an in-vivo exposure from the hierarchy constructed in session two and to remain in that session at least 45 minutes or until the anxiety decreased. They were also required to complete a monitoring form of this homework activity. Additional coping skills practise was also set for homework.

Coping skills were taught in the order described in Foa's manual. These were based on other treatment approaches and included cognitive restructuring (Ellis and Harper, 1975; Beck, Rush, Shaw, and Emery, 1979), guided self dialogue (Meichenbaum, 1977), and the use of covert modelling and role play (Vernon and Kilpatrick, 1983).

EMDR The full standard 8-phase EMDR procedure was used as described by Shapiro (1995). Following assessment each client was given relaxation-breathing strategies which he/she was encouraged to practise. In the second session the Preparation Phase was administered including the establishment of appropriate expectations. The second session also included the establishment of the target memory and Desensitization was begun. This involved having the client focus on the most distressing portion of the selected trauma memory while simultaneously moving his/her eyes from side to side by following the therapist’s fingers across the line of his or her visual field. The speed and number of movements depended on the client’s responses.

In general the therapist asked the client to voice any associations to the trauma material at the end of each set of eye movements and for the next set of eye movements the person was then encouraged to stay focussed on whatever had emerged. However, if there seemed to be a failure in the progression of material, as defined by two consecutive eye movement sets occurring without any change, then one of the unblocking procedures was used (as described in Shapiro, 1995). When distress dissipated following this procedure, the participant was asked to refocus on the memory and the procedure was repeated until the participant was unable to identify any portion of the memory that was still associated with distress.

At this point, the therapist checked the participant's degree of arousal to the trauma selected for treatment. This was done using an 11-point (0 = no discomfort; 10 = highest possible discomfort) Subjective Units of Distress Scale (SUDS; Wolpe, 1982). When the SUDS score reached 0 or 1, the Installation Phase began which involved having the client pair a positive cognition with the original trauma information while doing eye movements. At the end of each set the participant was asked to hold the current memory of the trauma and rate the believability of the positive cognition on a 7-point scale (1 = completely untrue; 7 = completely true). Once this rating had reached a stable 6 or 7 the Body Scan Phase was implemented. The participant was asked to focus on any residual physical distress and eye movements were continued, usually until the distress was eliminated. The session concluded with a debriefing. If any distress remained, an imagery technique was used to facilitate relaxation.

Subsequent sessions began with the Re-evaluation Phase of the EMDR protocol. Past trauma material was assessed for the most disturbing aspects, and if disturbing material remained then this was further targeted with EMDR. Once this had been processed towards resolution, any present stimuli that either elicited a trauma response or any potential future situation that the therapist or client identified as likely to elicit disturbing trauma-related emotions or problematic behaviors was then targeted.

Results

A Chi-Square test for independence indicated no significant differences between the two treatment groups in amount of prior therapy, current involvement in litigation, drug use, education level, employment status, family psychiatric history, prior traumas, or past incidents of abuse in the person's family background (see Table 1). An independent t-test analysis also found no significant differences between the groups on age or time between the trauma and participation in the study (see Table 2). Although 5 males participated in the EMDR treatment and 8 males in the SITPE, this difference was not significant (Pearson Chi-Square = 1.51, p=.22). Independent t-tests were used to investigate differences between the treatment groups on pretreatment measures. No differences were found for the IES (t (22) = .11, p = .91), BDI (t (22) = 1.05, p = .31), SI-PTSD (t (22) = 1.63, p = .12), or MMPI-K (t (22) = 1.31, p = .21). Therefore the groups appeared to be equivalent on major variables.

Insert Table I here

The length of time between the trauma and initial assessment for the study ranged from 2 to 71 months with a mean of 14.92 and a standard deviation of 15.71. One participant at the lowest end of the range was allowed onto the waiting list at one month post-trauma, thus potentially satisfying criteria for PTSD, and treatment was begun at 10 weeks post-trauma, 2 weeks before the 3-month mark which, by convention, defines PTSD as chronic.

Insert Table 2 here

At pretreatment the mean score for all participants on the IES was in the severe range (55.3) and in the moderately severe range on the BDI (21.4). Scores were also high on the SI-PTSD (39.7). On the MMPI-K scale, 70.8% of the sample scored above the T score cut-off point of 65. The mean MMPI-K T-score was 76.83. Therefore this group was significantly traumatised.

Decreases in mean scores during the 6-week waitlist period and during treatment on two self-report measures were investigated using a paired t-test (see Table 3). Scores on the BDI decreased more over the treatment phase than over the pretreatment phase, t (23) = 2.60, p < .05, as did scores on the IES, t (23) = 5.63, p < .001. Thus improvements during the treatment period were not due to spontaneous remission.

Insert Table 3 here

Means and standard deviations for all the dependent variables on each assessment occasion are presented in Table 4. A decrease in symptom severity is signified by a decrease in outcome scores for all measures. There appeared to be a greater improvement in outcome scores across all measures for participants receiving EMDR (see Figure 1). A multivariate analysis of co-variance (MANCOVA) was used to test whether or not following treatment the scores on SI-PTSD, IES, BDI and MMPI-K differed significantly between the two treatments. Pretreatment scores were used as covariates. The assumption of homogeneity of regression was tested by assessing the degree of interaction between the independent variable and the covariates. The results showed that there was sufficient homogeneity to use MANCOVA Wilks Λ(8,20)= .33 ( F=1.87, η² =.43, p=.122). MANCOVA is also based on the assumption that the dependent variables are intercorrelated. An examination of these correlations shows that this is true for the measures used in this study (Table 5).

A MANCOVA was conducted using scores at posttreatment as the dependent variable. There was no significant difference between conditions immediately after treatment Wilks Λ(4,15)= .73 ( F=1.37, η² =.27, p=.29).

Differences between the two treatments at follow-up on the outcome variables of SI-PTSD, IES, BDI and MMPI were then tested for significance using a MANCOVA. The scores at follow-up were used as the dependent variable and the scores prior to treatment were used as covariates. There was a significant main effect for condition favoring EMDR Wilks Λ(4,15)= .55 ( F=3.08, η² =.45, p <.05). Univariate tests of between-subjects effects showed significant differences on the IES, F (1,18)=8.04, η² =.31, p<. 05; BDI, F (1,18)=12.15, η² =.40, p<. 001; SI-PTSD, F (1,18)=6.74, η² =.27, p<. 05; MMPI-K, F (1,18)=6.32, η² =.26, p<. 05.

Given the finding of significant differences in treatment effects over the pretreatment to follow-up period but not during the pretreatment to posttreatment period, the significance of changes that occurred between posttreatment and follow-up was investigated. A MANCOVA was conducted using scores at follow-up as the dependent variable and posttreatment scores as covariates. There was no significant difference between conditions Wilks Λ(4,15)= .73 ( F=1.42, η² =.28, p=.28). Thus the finding of differences at follow-up probably reflects a cumulative differential treatment effect rather than any particular dramatic change during the follow-up period (see Figure 1)

Differences in improvement on the two intrusion measures between the two treatments were tested with MANCOVA (see Table 6). Scores on the variables at posttreatment were used as dependent variables and the pretreatment scores on these measures as covariates. There was a significant main effect for condition favouring EMDR, Wilks Λ(2,19)= .66 ( F=4.91, η² =.34, p <.05). Univariate tests showed that only intrusion scores on the IES differed significantly between the conditions at posttreatment, F (1,20)= 9.74, η² =.33, p<. 005.

Differences between the two treatments on the intrusion measures were also tested at follow-up with MANCOVA. Scores on both the structured interview and self-report measures at follow-up were used as dependent variables and the initial scores on these measures were used as covariates. There was a significant main effect for condition in the expected direction, Wilks Λ(2,19)= .58 ( F=6.99, η² =.42, p<. 005). Univariate tests of between subjects effects showed significant differences on both the IES scores, F (1,20)=11.80, η² =.37, p<. 005, and the SI-PTSD, F (1,20) = 11.71, η² =.37, p < .005. There were no significant differences between the treatments on avoidance measures either at posttreatment Wilks Λ(2,19)= .99 ( F=.09, η² =.01, p=.92) or at follow-up Wilks Λ(2,19)= .80 ( F=2.41, η² =.20, p=.12).

To compare the effect sizes in the current study with those obtained in earlier studies, a Cohen's d statistic was calculated by determining the difference between the two means and dividing by the pooled variance. These within groups effect sizes are presented in Table 7.

Both treatments proved to be highly effective with negligible outcome differences on diagnostic status. At posttreatment, 83% of the participants in the EMDR condition and 75% of those in SITPE no longer met the criteria for PTSD as measured by the SI-PTSD. At follow-up 83% from each condition no longer met these criteria.

Another means of considering clinically significant change is by using a cut-off score of the pretreatment mean less two standard deviations, as recommended by Jacobson and Truax (1991). In the present study those participants scoring below 37 on the IES would be regarded as having clinically significant improvement. Using this criterion, each of the treatments produced clinically significant improvement in 66.7% (8) of the participants at posttreatment. Using the same criterion, at follow-up 91.7% (11) of EMDR participants compared to 50% (6) of the SITPE participants had achieved clinically significant improvement. This difference was statistically significant (Pearson Chi-Square = 5.04, p<. 05).

Fidelity ratings were satisfactory. Using the EMDR checklist, the rater's mean fidelity score was 5.2 and the median was 6.0 on the 1-7 scale.

Similar high scores were obtained in the integrity ratings of the SITPE treatment. Agreement between the two SITPE raters was substantial (r=.87). The median rating was 6.0 and the mean rating was 6.33.

A t-test for independent samples indicated that the difference between the mean ratings obtained for the 10 EMDR and SITPE tapes was not significant t(8)= 2.130, p=.07.

Discussion

Both the EMDR and SITPE procedures produced significant improvement on self-report measures of depression and trauma in comparison to a waiting period. The effects of treatment were large to very large according to criteria suggested by Cohen (1977) and both treatments required only a small number of sessions. Although all participants met the criteria for PTSD at the start of treatment, 83% no longer met these criteria at follow-up.

The study excluded participants on the basis of possible psychosis, personality disorder, or active substance abuse; however, most participants had a significant history of trauma in addition to the index event, as well as a significant history of prior mental health problems. About half of the participants were involved in litigation at the time of treatment, and well over half were unemployed. This was a relatively complex and challenging population such as is found in actual clinical practice; thus, the findings are directly relevant to clinical practice with this type of client.

There were no significant differences between groups on any of the global measures immediately after treatment. However, small but statistically significant differences were found at treatment follow-up on measures of trauma symptomatology and distress. The comparatively greater improvement over the follow-up period after EMDR treatment is consistent with the results of Van Etten and Taylor (1998). In one of the few earlier studies to directly compare traditional behavioral procedures to EMDR, there were also larger reductions in trauma measures in the EMDR group, although those improvements did not reach statistical significance (Vaughan et al., 1994).

There was no significant difference between the two treatments according to the number of people meeting PTSD diagnosis at posttreatment or follow-up. Using the criterion of clinically significant improvement defined as symptom reduction of at least two standard deviations below the pretreatment score, there was no difference between the treatments at posttreatment but at follow-up almost twice as many EMDR participants had reached this criterion than participants in SITPE.

These findings appear at odds with the follow-up data reported in another study comparing similar behavioral procedures used in the current study to EMDR (Devilly & Spence, 1999). In that study, participants in the behavioral treatment improved further during the follow-up period while those in the EMDR condition appeared to return to baseline.

The conflicting findings lead to questions about the nature of the treatment delivered in each study. In the present study, extensive procedures were followed to ensure treatment fidelity. Therapy administered by the first two authors was reviewed by a fidelity rater in a pilot project to ensure fidelity with the treatment under investigation. Subsequently, separate raters who had training in, and were identified with each treatment were used to assess the fidelity of the therapy in each condition. All raters were experienced clinicians in treating PTSD. Two raters also had more than 5 years experience as a trainer in their respective models. Not only were high fidelity ratings obtained for each treatment by raters with impeccable credentials; the minimal dropout and improved outcomes were at levels consistent with those achieved in previous research.
In contrast, Devilly and Spence (1999) used the same fidelity rater for both treatments, with no indication that the rater had any special qualifications beyond being a certified mental health practitioner with some training in each of the methods. The standard training in EMDR has not always been sufficient to ensure treatment fidelity (see Greenwald, 1996), and according to the EMDR International Association (1999), an additional period of supervised practice is required for a basic level of competence. Much more supervised experience is required to qualify as a supervisor (trainers have additional requirements), presumably the level one would want for a fidelity rater. Although equivalent credentialing may not exist for behavior therapists, a fidelity rater should have advanced qualifications as may be available. Since the credibility of the Devilly and Spence rater is questionable, it is unclear how his or her view of fidelity correlates with actual practice.

The quality of the EMDR treatment delivered in the Devilly and Spence study may be called into question on other grounds. In the present study, the EMDR group showed an effect size of 1.97 for self-report measures and 2.48 for observer-rated measures which although larger than the mean reported in the Van Etten and Taylor meta-analysis were within the 90% confidence intervals for EMDR. One possible reason for our slightly larger than average effect size could be that there were seven treatment sessions compared to an average of 4.6 in the studies that were reviewed in the meta-analysis. In contrast the effect size of .32 reported by Devilly and Spence for EMDR at follow-up is well outside of those intervals, suggesting that the treatment was less potent than usual. In particular, Devilly and Spence do not mention the use of Re-evaluation phase of the EMDR procedure. One of the crucial aspects of this phase is to have the person focus on possible difficult situations in the future and to process associated anticipated distress with accompanying eye movements. The exclusion of this phase may account for the relatively low effect size at follow-up given that aversive events that may have occurred in the follow-up period were not targeted during treatment. In contrast, it is reasonable to surmise that the cognitive-behavioral treatment in the Devilly and Spence study was delivered properly, in that the principal investigators were presumably well versed in the CBT protocol they devised and named.

Whereas the EMDR treatment conducted by Devilly and Spence may not have adequately replicated the standard protocol, the same does not appear applicable to the SITPE treatment in our study. We obtained a mean effect size for this treatment procedure on self-report measures of 1.01 (7 sessions) which is similar to the 1.10 (9 sessions) reported by Devilly and Spence – although both are lower than the 1.63 (14.8 sessions) reported by Van Etten and Taylor. Similarly, our attrition rates (14%) were equivalent for each treatment and to other EMDR and traditional Behavior Therapy studies (Van Etten and Taylor, 1998). This contrasts with the unusually high attrition rate of 35% for EMDR reported by Devilly and Spence, much of which occurred prior to the first session involving eye movement.

EMDR resulted in greater reduction in intrusive symptoms than SITPE. At follow-up there were large and significant differences on both observer-rated and self-reported intrusion measures. However, immediately after treatment only the self-report intrusion measure showed significantly greater changes for the EMDR treatment. This finding is similar to Vaughan et al. (1994) who reported greater reduction in symptoms of intrusion for the EMDR condition.

The superiority of EMDR over SITPE for intrusion symptoms may be due to the unique aspects of the EMDR intervention that focuses more on treating intrusions. In EMDR sessions, participants are frequently asked in the session "What do you get now?" - a question which would elicit any intrusive phenomena. When such material is reported, it is targeted for desensitization. In contrast, SITPE appears to more directly target avoidance behavior. The SITPE condition included a substantial homework component where, from the third session, participants were given tasks that encouraged them to face stimuli that they had previously avoided. These tasks occupied seven hours of the participant’s week and thus represent a very intensive aspect of the intervention. However, there were no significant differences between the two treatments on any of the avoidance measures at posttreatment or follow-up.

EMDR appears to be a more efficient treatment than SITPE. In the current SITPE protocol each person was set approximately 7 hours of homework between each treatment session (totalling 42 hours). Although compliance was less than optimal, therapists administering SITPE estimated from the participants’ homework diaries that the average person completed 28 hours of homework. This was a similar compliance rate to that reported in other studies that formally assessed the degree to which homework tasks were completed with this type of intervention (Marks et al., 1998; Scott and Stradling, 1997). This compares to an estimated 3 hours homework for EMDR.

A possible further advantage for EMDR is that participants may prefer it to SITPE. In EMDR the person does not have to recount details of their trauma experiences to the therapist whereas this is a necessary aspect of SITPE. Other investigators examining participants’ perceptions of the treatment have all reported that EMDR is preferred to other modalities. For example, Vaughan et al. (1994) found that participants rated their EMDR therapist as more warm and supportive than their behavioral therapist despite the same therapist being used in both treatment conditions. In one study (Ironson, Freund, Strauss, & Williams, in press), the level of distress post-session was lower for EMDR than for the traditional exposure treatment. Other authors have also suggested that EMDR is preferred by participants over other treatment methods (Boudewyns & Hyer, 1996; Pitman et al., 1996), and one study reported a lower dropout rate for EMDR (0/10) compared to prolonged exposure (3/10) (Ironson et al, in press). However, participant preference was not assessed in the current study and any differences were not substantial enough to affect the retention rates.

A possible limitation of the present study was the rather small size of the sample. However, the number of participants at follow-up compares favorably with other studies in this area. For example, Foa et al. (1991) maintained only 9 subjects per condition and Vaughan et al. (1994) averaged 12. As well, the effect sizes for the differences in intrusion measures were substantial. However, the present study clearly requires replication with more participants.

Another limitation of the present study was that the assessor administering the structured interview posttreatment and at follow-up was not blind to treatment assignment or in all cases independent to the therapist. However, because the standardized self-report trauma measures were generally consistent with the interview data, this probably did not influence the results. Indeed, in nearly all the analysis, the mean effect sizes for the observer-rated measures were less than the self-report measures.

It is unclear to what extent conclusions based on the SITPE treatment used in this study may be generalized to other exposure and cognitive treatment packages. A recent study found that combining stress inoculation training and prolonged exposure was less effective than prolonged exposure on its own, although not significantly different from stress inoculation training on its own (Foa et al., 1999). It was argued that perhaps the inclusion of exposure and the stress inoculation training into the one condition might lead to information overload for participants, thus making it less effective than prolonged exposure. However, in that particular study the PE had a lower dropout rate. This may have confounded the interpretation as the difference between the treatments was only found when treatment non-completers were included in the analysis. In contrast, another study that compared exposure only with cognitive therapy only and with the combination found no significant differences between the 3 treatments (Marks et al., 1998). Consideration of these findings is complicated by the fact that Foa and colleagues were treating only female assault victims, whereas Marks and colleagues were treating a general adult PTSD sample. Thus the optimal combination of skills training, cognitive therapy and exposure in a traditional behavioral treatment programme of PTSD remains uncertain.

Finally, it is possible that designating a treatment duration of seven sessions may have put the SITPE condition at a disadvantage in that a larger number of sessions may have increased its effectiveness. Indeed, Foa et al (1999) speculated that, in a combined approach, even more sessions might be needed for each treatment component to be optimally effective. On the other hand, the effect size obtained in the current study for SITPE compares quite favorably with those obtained in other studies of traditional Behavior Therapy approaches, so it is unlikely that SITPE was unfairly represented here. Still, it is possible that SITPE might be improved with additional sessions. The decision to use seven sessions across treatment conditions was meant to give each treatment a fair chance while allowing a comparison of treatments over the same number of sessions.

It is encouraging that both treatments were highly effective with a challenging PTSD population in relatively few sessions and with low dropout rates. Although there was considerable clinically significant improvement in symptomatology, after the 7-session course of treatment participants were still indicating some distress. In clinical practice the option of continuing treatment might rectify this.

Considering the controversy and confusion that has surrounded EMDR, a particular strength of this study was the emphasis on ensuring adherence to the treatment protocols as specified by the respective treatment manuals. A number of reviewers who analyzed the contradictory findings regarding EMDR have concluded that it is highly effective for trauma treatment, but only when done properly (Greenwald, 1996; Lee et al, 1996; Shapiro, 1999). This view is supported by a recent meta-analysis that found that good fidelity in EMDR studies was the best predictor of positive outcome (Maxfield & Hyer, in press). The present findings are consistent with that understanding. Furthermore, EMDR may be particularly difficult to master (Shapiro, 1991), resulting in potentially inadequate practice even by those with some formal training in the method (Greenwald, 1996). Further study of EMDR should emphasize treatment fidelity to ensure that results are meaningful and can be interpreted.

This study compared the two major treatments for PTSD by the same clinicians who were competent in both methods, and featured nearly all of the components of optimal controlled research called for by Foa and Meadows (1997). The sample consisted of a PTSD population which can be considered to be representative, within the limits imposed by the selection criteria, of those presenting with PTSD in clinical practice. These findings extend the previous research support for both SITPE and EMDR, and indicate that these approaches should be considered as first line treatments for PTSD.

In this study EMDR was somewhat more effective in terms of treatment outcome, particularly in regard to intrusive symptoms at least in the intermediate term. It was also more efficient, in that it required much less homework. This result awaits replication.

References

Beck, A.T., Rush, A.J., Shaw, B.F. & Emery, G. (1979). Cognitive therapy of depression. New York: Guildford Press.

Boudewyns, P.A., & Hyer, L. (1996). Eye movement desensitisation and reprocessing (EMDR) as a treatment for post-traumatic stress disorder (PTSD). Clinical Psychology and Psychotherapy, 3(3), 185-195.

Chambless, D, L., Baker, M.J., Baucom, D.H., Beutler, L.E., Calhoun, K.S., Crits-Christoph, P., Daiuto, A., DeRubeis, R., Detweiler, J., Haaga, D.A.F., Johnson, S.B., McCurry, S., Mueser, K.T., Pope, K.S., Sanderson, W.C., Shoham, V., Stickle, T., Williams, D.A., and Woody, S.R. (1998). Update on empirically validated therapies II. The Clinical Psychologist, 51(1), 3-16.

Chemtob, C. M., Tolin, D. F., van der Kolk, B. A., & Pitman, R. K. (2000). Eye movement desensitization and reprocessing. In E. B. Foa, T. M. Keane, & M. J. Friedman (Eds.), Effective treatments for PTSD: Practice guidelines from the International Society for Traumatic Stress Studies. New York: Guilford Press.
Cohen, J. (1977). Statistical power analysis for the behavioral sciences. New York: Academic Press.

Davidson, J.R.T., Smith, R., & Kudler, H. (1989). Validity and reliability of the DSM-III-R criteria for post traumatic stress disorder. The Journal of Nervous and

Mental Disease, 177(6), 336-341.

Davidson, J.R.T. & Foa, E.B. (1993). Posttraumatic stress disorder: DSM-IV and beyond. Washington, D.C: American Psychiatric Press Inc.

Devilly, G.J. and Spence, S.H. (1999). The relative efficacy and treatment distress of EMDR and a cognitive Behavior trauma treatment protocol in the amelioration of Post Traumatic Stress Disorder. Journal of Anxiety Disorders, 13 (1-2), 131-157.

Ellis, A. & Harper, R. A. (1975). A new guide to rational living. North Hollywood, CA: Wilshire Books.

EMDR International Association. (1999). Certification in EMDR. Austin, TX: Author. Available on the Internet at: http://www.emdria.org.

Foa, E.B., Rothbaum, B.O., Riggs, D.S., & Murdock, T.S. (1991). Treatment of posttraumatic stress disorder in rape victims: A comparison between cognitive-behavioral procedures and counselling. Journal of Consulting and Clinical Psychology, 59(5), 715-723.

Foa, E. V., Dancu, C. V., Hembree, E. A. Jaycox, L H., Meadows, E.A., and Street, G. P. (1999). Comparison of exposure therapy, stress Inoculation training and their combination in reducing post traumatic stress disorder in female assault victims. Journal of Consulting and Clinical Psychology Volume, 67(2), 194-200.

Foa, E.B., Hearts-Ikeda, D., & Perry, K.J. (1995). Evaluation of a brief cognitive-behavioral program for the prevention of chronic PTSD in recent assault victims. Journal of Consulting and Clinical Psychology, 63(6), 948-955

Foa, E.B., and Meadows, E.A. (1997). Psychological treatments for PTSD: A critical review. Annual Review of Psychology, 48, 449-480.

Greenwald, R. (1996). The information gap in the EMDR controversy. Professional Psychology: Research and Practice, 27, 67-72.

Hamilton, M. (1959). The assessment of anxiety states by rating. Journal of Medical Psychology, 32, 50-55.

Hamilton, M. (1967). Development of a rating scale for primary depressive

illness. British Journal of Social Clinical Psychology, 6, 278-296.

Horowitz, M.J., Wilner, N. & Alvarez, W. (1979). The Impact of Event Scale: a measure of subjective stress. Psychosomatic Medicine, 41, 209-218.

Ironson, G. I., Freund, B., Strauss, J. L., & Williams, J. (in press). A comparison of two treatments for traumatic stress: A pilot study of EMDR and prolonged exposure. Journal of Clinical Psychology.

Jacobson, N.S., Truax, P. (1991). Clinical significance: A statistical approach to defining meaningful change in psychotherapy research. Journal of Consulting and Clinical Psychology, 59(1), 12-19.

Keane, T.M., Malloy, P.F., & Fairbank, J.A. (1984). Empirical development of an MMPI subscale for the assessment of combat-related posttraumatic stress disorder. Journal of Consulting and Clinical Psychology, 52, 888-891.

Keane, T.M., Wolfe, J., & Taylor, K.L. (1987). Post-traumatic stress disorder:

Evidence for diagnostic validity and methods of psychological assessment. Journal of

Clinical Psychology, 43, 32-43.

Lee, C.W., Gavriel, H., & Richards, J. (1996). Eye movement desensitisation: Past research, complexities, and future directions. Australian Psychologist, 31(3), 168-173.

Marks, I., Lovell, K., Noshirvani, H., Livanou, M., & Thrasher, S. (1998). Treatment of posttraumatic stress disorder by exposure and/or cognitive restructuring: A controlled study. Archives of General Psychiatry, 55, 317-325.

Maxfield, L., & Hyer, L. A. (in press). The relationship between efficacy and methodology in studies investigating EMDR treatment of PTSD. Journal of Clinical Psychology.

Meichenbaum, D. (1977). Cognitive-Behaviour Modification: an intergrative approach. New York: Plenum Press.

Newman, E., Kaloupek, D.G., & Keane, T.M. (1996). Assessment of posttraumatic stress disorder in clinical and research settings. In van der Kolk, B.A., McFarlane, A.C., & Weisaeth, L. (Eds), Traumatic stress: The effects of overwhelming experience on mind, body and society, New York: Guildford Press.

Pitman, R.K., Orr, S.P., Altman, B., Longpre, R.E., Poire, R.E., & Macklin,

M.L. (1996). Emotional processing during eye movement desensitization and

reprocessing therapy of Vietnam Veterans with chronic posttraumatic stress disorder.

Comprehensive Psychiatry, 37, (6), 419-429.

Rothbaum, B.O., & Foa, E. B. (1996). Cognitive behavioral therapy for posttraumatic stress disorder. In van der Kolk, B.A., McFarlane, A.C., & Weisaeth, L. (Eds.), Traumatic stress: The effects of overwhelming experience on mind, body and society, New York: Guildford Press.

Scott, M. J. and Stradling, S.G. (1997). Client compliance with exposure treatments for Post Traumatic Stress Disorder. Journal of Traumatic Stress, 10 (3), 523-526.

Shapiro, F. (1991). Eye movement desensitization & reprocessing procedure:

From EMD to EMDR - A new model for anxiety & related traumata. Behavior

Therapist, 14, 133-135.

Shapiro, F. (1995). Eye movement desensitization and reprocessing: Basic principles, protocols, and procedures. Guildford Press: New York.

Shapiro, F. (1999). Eye movement desensitization and reprocessing (EMDR) and the anxiety disorders: clinical and research implications of an integrated psychotherapy treatment. Journal of Anxiety Disorders, 13(1-2), 35-67.

Van Etten, M.L., & Taylor, S. (1998). Comparative efficacy of treatments for posttraumatic stress disorder: a meta-analysis. Clinical Psychology and Psychotherapy, 5, 126-144.

Vaughan, K., Armstrong, M.F., Gold, R., O’Connor, N., Jenneke, W., & Tarrier, N. (1994). A trial of eye movement desensitisation compared to image habituation training and applied muscle relaxation. Journal of Behavior Therapy and Experimental Psychiatry, 25, 283-291.

Veronon, L.J. & Kilpatrick, D. G. (1983). Stress management for rape victims. In D. Meichenbaum & M.E. Jaremko (Eds.), Stress Reduction and Prevention. New York: Plenum Press.

Wolpe, J. (1982). The practice of behavior therapy. Pergamon Press, New York.

Appendixes

Table 1. Comparison of Background Variables in each Treatment Condition.

(a) None of the differences were statistically significant p > .05

Table 2. Mean Age and Time Between Trauma and Entering Treatment for each Treatment Condition.

Standard deviations in brackets.

Table 3. Comparison of Changes in Scores During Waitlist and Treatment.

Standard deviations in brackets.

Table 4. Means and Standard Deviations for the Outcome Measures by Treatment Group.

(a) Adjusted means based on MANCOVA

Table 5. Pearson correlations between measures.

*significant at p<.05

Table 6. Means and Standard Deviations for the Intrusion and Avoidance Measures of PTSD by Treatment Group.

Table 7. Mean within group effect sizes (Cohen's d) of treatment for the pretreatment to follow-up period across different studies.

Figure Captions

Figure 1. Effects of treatment condition on the outcome variables

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Figure 1.

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Figure 1 (con't).