PTSD: Treatment Efficacy and Future Directions
By Shawn P. Cahill, PhD, and Edna B. Foa, PhD |
March 1, 2007
Dr Cahill is assistant professor of clinical psychology
in psychiatry and Dr Foa is professor of
clinical psychology in psychiatry and director of
the Center for the Treatment and Study of Anxiety
at the University of Pennsylvania.
Although most people in treatment studies benefit from CBT, many patients receive only partial benefit and some patients do not benefit at all. In addition, access to the treatments described above is currently quite limited: nationwide, few therapists are trained to use CBT for PTSD.24 Research on improving treatment outcome and disseminating CBT has begun but is less advanced than research demonstrating the basic efficacy of this approach.
Combining CBT interventions
One method that may improve outcome is to combine separately efficacious treatments. Five studies have investigated whether combining CBT interventions results in greater improvement. Foa and colleagues10 investigated whether the combination of exposure therapy plus SIT resulted in better outcome than either treatment alone. Marks and coauthors25 investigated whether the combination of exposure therapy plus cognitive restructuring resulted in better outcome than either treatment alone. Unfortunately, neither study found evidence for the superiority of combined treatment over the constituent treatments. Consistent with the study by Marks and coauthors,25 Paunovic and Ost26 and Foa and coinvestigators27 found comparable outcomes between exposure therapy alone and exposure therapy combined with cognitive restructuring.
In contrast, Bryant and colleagues28 found that adding cognitive restructuring enhanced the efficacy of exposure therapy. However, the exposure therapy program in their study included only imaginal exposure, whereas the studies that did not find augmentation of exposure therapy with the addition of either SIT10 or cognitive restructuring25-27 used both imaginal and in vivo exposure. Thus, it may be that imaginal exposure alone can be enhanced by the addition of either in vivo exposure or cognitive restructuring, but the combination of imaginal plus in vivo exposure is not further enhanced by the addition of cognitive restructuring or SIT.
Medication and CBT intervention
At present, 2 medications have received FDA approval for PTSD, sertraline(Drug information on sertraline)29,30 and paroxetine(Drug information on paroxetine).31,32 In a variation of the strategy of combining treatments, Rothbaum and colleagues33 investigated whether adding exposure therapy to medication for PTSD resulted in enhanced outcome. Patients received 10 weeks of open-label treatment with sertraline and were then randomly assigned to continue receiving sertraline alone for an additional 5 weeks or to continue taking sertraline and receive 10 sessions of exposure therapy administered twice weekly.
Overall, there was a significant reduction in PTSD severity during the course of the initial 10 weeks of treatment with sertraline, followed by a modest effect during the period of augmenting sertraline with CBT. However, an exploratory analysis in which patients were separated based on their response to sertraline at week 10 as either excellent responders or partial responders revealed a substantial augmentation effect for medication partial responders. Among medication partial responders who received only sertraline, there was a 35% reduction in PTSD severity from pretreatment to week 10, and at week 15 the overall reduction was 30%, indicating a small and statistically nonsignificant increase in PTSD severity from week 10 to week 15. Partial responders to medication who received CBT augmentation showed a reduction of 37% from pretreatment to week 10 and overall reduction of 62% from pretreatment to week 15, indicating a clinically and statistically significant (P < .001) improvement from week 10 to week 15. The between-group effect size at week 15 for augmenting sertraline with CBT among medication partial responders was 0.90.
Another strategy for improving outcomes is to provide the same treatment for a longer duration, a strategy that is commonly used in clinical practice: where there is improvement in symptoms but not complete response, continuation with the same treatment is recommended. Efficacy studies, however, typically implement the treatments of interest for a set period without regard to the patient's symptom status. In an exception to the rule, Foa and associates27 used flexible dosing: patients with PTSD symptoms that decreased by at least 70% at session 8 terminated treatment at session 9. The remaining patients were offered additional sessions, to a maximum of 12. Fifty-eight percent of patients who completed at least 8 sessions received extension sessions. Results for this group indicated that further improvement was achieved during the extension period.
On average, these patients showed a 31% reduction in PTSD severity at session 8. After the extension sessions, the average reduction in PTSD severity compared to pretreatment was 60%. Thus, research is beginning to address the need to develop and evaluate strategies for enhancing treatment outcome for those who show partial response to existing treatment programs; however, further research is needed.
Disseminating the use of CBT for PTSD
A second area in which research is just beginning is the development and evaluation of methods to disseminate the use of CBT for PTSD.34,35 Foa and coauthors27h sites for the duration of the study.
Results indicated that, before treatment, patients were comparable across sites on PTSD severity and depression. More important, the effects of treatment were comparable across sites. This study demonstrated that CBT could be transported from academic-based clinics to community-based clinics under conditions of close collaboration with an academic center. Additional research is needed to determine whether community-based institutions can sustain their use of CBT when the level of contact with the academic center is substantially reduced, along with research to identify the most efficient methods to disseminate CBT to large numbers of therapists.
Dr Cahill reports that he has received research
support on studies of treatment for PTSD from
NIMH and National Institute of Alcohol Abuse and
Addiction (NIAAA); and honoraria from invited
lectures and workshops on the nature and treatment
of PTSD. Dr Foa reports that she has received
research support on studies of treatment
for PTSD from NIMH and NIAAA; honoraria from
invited lectures and workshops on the nature
and treatment of PTSD; and royalties from books
on the treatment of PTSD, Treating the Trauma of
Rape and Reclaiming Your Life After Rape.
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