the most common, distressing, and disabling medical consequences of
combat or other extremely stressful life events is posttraumatic stress
disorder (PTSD). Exposure therapy is the first line treatment for PTSD
and it is a type of behavioral therapy where patients confront their
fears in a safe environment. Although it is an effective treatment, many
patients still experience symptoms after treatment and there is a
relatively high drop-out rate.
In an effort to improve existing treatments, a new study appearing in
this week has tested a novel
hypothesis about the treatment of PTSD derived from prior work in animal
models and other anxiety disorders. They examined whether the impact of
psychotherapy could be enhanced by administering D-cycloserine (DCS), a
drug that does not directly treat the symptoms of PTSD, but rather
promotes neuroplasticity, i.e., makes brain circuits better able to
remodel themselves in the context of experience.
To test this, researchers recruited individuals with PTSD, all of whom
received up to 10 weekly sessions of exposure therapy. They were
randomized to receive doses of either DCS or placebo before each
session, but did not know which they were receiving. The severity of
their symptoms was assessed before and after treatment.
All patients experienced a reduction in symptoms due to the exposure
therapy, regardless of whether they had received DCS augmentation or
placebo. However, DCS did enhance the effects of exposure therapy in a
specific subgroup of patients. Those who had more severe PTSD prior to
treatment and needed longer treatment had a greater reduction in
symptoms when they received DCS, compared to those who received placebo.
"Our study showed that some PTSD patients respond well and fast to
exposure and for them, there seems no need to augment the therapy. In
contrast, those patients with severe PTSD symptoms and who fail to
respond to exposure sessions may benefit from augmentation with DCS,"
explained first author Dr. Rianne de Kleine. "It seems that DCS is
beneficial for exactly those patients we aimed for: the more severe
patients who do not respond to first-line treatment."
"This approach may have important implications for the treatment of
PTSD. Two decades of brain research suggests that severe psychological
stress causes atrophy of some of the fine connections in the brain and
reductions in the volume of brain regions involved in emotion and
memory. Thus, individuals with PTSD may have deficits in neuroplasticity
that get in the way of effective treatment," commented Dr. John
Krystal, Editor of Biological Psychiatry
"D-cycloserine may reduce this deficit in neuroplasticity and increase
the response to psychotherapy, in this case a psychotherapy approach
that involves exposing people to reminders and memories of the trauma."
The authors conclude that additional work is warranted to explore
whether this combination can become an effective intervention to treat
the symptoms of PTSD.