"Significant gaps" in the evidence underlying nearly all
treatments for posttraumatic stress disorder make it impossible to judge their
value, according to a study released in October by the Institute of Medicine
Poorly designed and executed studies have failed to include enough veterans
or account for important comorbidities like depression, substance abuse, or
traumatic brain injury, said the IOM committee that conducted the study.
Only exposure therapies had amassed sufficient evidence of efficacy, said
the committee, which grouped prolonged exposure therapy with other approaches
like cognitive-behavioral therapy or cognitive-processing therapy that also
include some element of exposure to reminders of trauma.
"Treatments may or may not be effective, and 'inadequate evidence'
doesn't mean treatments don't work," said committee chair Alfred Berg,
M.D., M.P.H., a professor of family medicine at the University of Washington
School of Medicine in Seattle, in a telephone news conference accompanying the
report's release. "We just don't know because of the [poor] quality of
The report's call for better, more relevant research resonated with many in
"There are not a ton of studies, and we should be funding more
research," said Patricia Resick, Ph.D., director of the National Center
for PTSD's Women's Health Sciences Division at the VA Boston Healthcare System
and a professor of psychiatry and psychology at Boston University. Resick is
starting to train 600 VA therapists in cognitive-processing therapy, which she
developed 20 years ago.
However, the report's high threshold for including and evaluating studies
created another dilemma.
"I think the IOM has set the bar too high," Resick told
Psychiatric News. "This is the harshest set of critiques I've
ever seen, and I would hate to limit our practice based on that."
The IOM committee eliminated many useful studies by applying current
standards to trials that were acceptable when they were designed, she said."
Trials take years to plan, run, and publish, but treatment must go
ahead in the meantime."
Others worried about the effects on patients' and therapists' attitudes
"This study will be valuable if it facilitates research, but not if
it decreases access or willingness to treat patients, especially using
medications," said Darrel Regier, M.D., M.P.H., director of APA's
Division of Research and executive director of the American Psychiatric
Institute for Research and Education, in an interview. "I'd hate to see
therapeutic nihilism come out of this report. There are not enough people
doing exposure-based psychotherapy to cover the need."
The IOM study began with a systematic search of the medical literature,
yielding 2,771 studies. Rigorous inclusion standards eliminated nonrandomized,
uncontrolled, or observational studies, so that only 90 randomized, controlled
trials remained for analysis.
"The committee may have used an overly conservative standard, but
that allowed them to make the most defensible statements," said Stevan
Hobfoll, Ph.D., a distinguished professor and director of the Applied
Psychology Center and the Summa-KSU Center for the Treatment and Study of
Traumatic Stress at Kent State University in Ohio. Hobfoll was not on the
committee but served as a peer reviewer prior to the report's release.
"Clearly, clinicians will use a looser standard, but the study will
inform their judgment," he told Psychiatric News.
A review of 37 clinical trials of pharmacotherapies found"
inadequate" evidence to determine the value of antidepressants,
benzodiazepines, anticonvulsants, alpha blockers, and second-generation
antipsychotics (such as olanzapine or risperidone) for treating PTSD.
The 53 studies of psychotherapies led the committee to conclude that only
exposure therapies had proven efficacy. They found the evidence inadequate to
determine the utility of eye-movement desensitizing and reprocessing,
cognitive restructuring, coping-skills training, and group therapy.
The committee also noted that many drug trials were funded by
pharmaceutical companies and that many trials of psychotherapies were
conducted by those who had developed them. Both of these patterns raised
questions of bias and generalizability, they said.
Taken together, studies of PTSD therapies carried out since the criteria
for PTSD were first included in DSM in 1980 "do not form a
cohesive body of evidence about what works and what does not work,"
wrote the committee in its report. Many studies lacked internal validity
because of high dropout rates and poor handling of missing data.
"The bottom line is the number of studies is small, and the quality
could be improved," said Farris Tuma, Sc.D., chief of the traumatic
stress research program at the National Institute of Mental Health, who was
not involved in preparing the report. "The report does the scientific
community a service and raises the bar for standards of treatment."
The IOM report is the third in a series requested by the Department of
Veterans Affairs asking for guidance in diagnosing, treating, and assessing
disability in veterans with PTSD. Coverage of the reports on diagnosis and
disability standards appeared in the July 21, 2006 and June 1 Psychiatric
News issues, respectively. The reports were originally commissioned
because of complaints that too many veterans were requesting disability
compensation for PTSD.
The current report was not intended to say which therapies did or did not
work or to guide clinical choices, but rather to serve as a guide to those
designing the next generation of clinical trials.
"Concluding that the evidence is inadequate to determine efficacy is
not the same as concluding that a treatment modality is inefficacious,"
said the authors. They added that they had found no evidence that any
treatment was harmful or ineffective.
These conclusions may raise questions for those familiar with existing PTSD
treatment guidelines. For instance, the VA's National Center for Posttraumatic
Stress Disorder recommends "SSRIs as first-line medications for PTSD
pharmacotherapy in men and women with military-related PTSD." APA's
practice guideline on acute stress disorder and posttraumatic stress disorder
says that SSRIs "represent reasonable clinical
However, the IOM committee noted that while there were more clinical trials
of SSRIs than of other drugs, outcomes were split in the seven most useful
studies. The largest study of SSRIs showed no improvement in primary PTSD
outcomes and saw many patients drop out.
APA's Steering Committee on Practice Guidelines is currently reviewing the
One member of the IOM panel dissented from the committee's conclusions on
medications, preferring to separate civilian from veteran populations and the
latter into chronic patients and those with more recent exposure to war.
"The effect of [SSRIs] in civilian and specific veteran
subpopulations must be noted as separate conclusions," wrote Thomas
Mellman, M.D., a professor of psychiatry at Howard University."
[P]redominantly male veteran populations with chronic PTSD are less
responsive to treatments in general."
Mellman also disagreed with the group's emphasis on the limitations caused
by the last observation carried forward method for handling data from subjects
who drop out of studies, an issue that also troubled Resick.
"I think they were overly critical on the dropout question,"
she said. "Saying that a 20 percent dropout rate for PTSD is too high is
too strict, given that avoidance is one of the prime symptoms of the
The report offered several recommendations in the light of its findings. In
the future, researchers should be required to standardize treatment and
outcome measures, define recovery, avoid conflict of interest, and find
acceptable ways to track subjects who drop out of trials or to account for the
dropouts' data. It also called for more research on veterans and suggested
that veterans groups might contribute to clinical trial design and
The VA announced in October that it will convene a consensus conference
with the Department of Defense and the National Institutes of Health to"
improve the designs and methodologies all three agencies will use in
future research studies" for PTSD, according to a press release.
Meantime, clinical practice should be informed by the committee's findings,
but not exclusively, said Hobfoll. Practitioners should judiciously apply the
empirical literature as the evidence warrants, he said.
"The report is not well suited to guide clinical care," added
Tuma. "If we rely solely on randomized, controlled trials, it would be
very difficult to develop clinical treatment guidelines. Guidelines combine
good science and clinical experience."
The IOM's report comes at a crucial time as many U.S. troops return from
war with PTSD and comorbidities.
"We need not just more research," said committee member David
Matchar, M.D., director and a professor of medicine at the Center for Clinical
Health Policy Research at Duke University, at the news conference. "We
need more research that will help clinicians in their practice."
"Treatment of PTSD: An Assessment of the Evidence" is