Another Weapon for Fighting Fear

PTSD exposure therapy treatment enhanced by D-cycloserine drug

(RxWiki News) While exposure therapy remains the first line of defense for post-traumatic stress disorder, it remains an imperfect treatment. But an inexpensive drug may enhance its effectiveness.

A recent study has found some evidence that patients experiencing especially severe PTSD may respond better to psychotherapy if they supplement it with the drug D-cycloserine (DCS).

"Ask your therapist about using D-cycloserine during exposure therapy."

Dr. Rianne de Kleine, of the Radboud University Nijmegen Behavioral Science Institute and Center for Anxiety Disorders Overwaal in the Netherlands, led the study to see if it was possible to improve exposure therapy outcomes for patients suffering from PTSD.

Exposure therapy involves repeatedly exposing a person to thinking about, discussing or even experiencing the traumatic events that caused their PTSD while they're in a safe place.

The goal is for people to begin associating those traumatic experiences with a safer environment as they get used to living with their memories and for the memories to lose their power over the person.

The treatment works, but it doesn't work for everyone. Many people drop out of psychotherapy, and others' symptoms persist.

Enter D-cycloserine, an antibiotic that has been used for many years to treat tuberculosis but has also been shown in the past several years to enhance "neuroplasticity." Neuroplasticity is the brain's ability to adapt to new experiences and rewire its circuits based on those experiences.

While a drug to enhance neuroplasticity does not treat PTSD symptoms directly, having a more "flexible" brain may help therapy stick better. So Dr. Kleine's team decided to test this theory.

With 67 patients suffering from PTSD due to a variety of traumatic experiences, Dr. Kleine's team gave 50mg of D-cycloserine or a placebo to patients an hour before an exposure therapy session.

All the patients went through 10 weekly sessions of exposure therapy. Neither the patients nor the doctor providing the medication knew whether they were getting D-cycloserine or a placebo.

The exposure therapy improved symptoms for all the patients, and the D-cycloserine appeared to help a subgroup of the patients, but not all of them.

Those patients with the most severe PTSD before treatment began and who required the longest amount of treatment were also those most likely to receive a benefit from taking D-cycloserine.

"Our study showed that some PTSD patients respond well and fast to exposure and for them, there seems no need to augment the therapy," said Dr. Kleine. "In contrast, those patients with severe PTSD symptoms and who fail to respond to exposure sessions may benefit from augmentation with D-cycloserine."

Though the number of participants was small in this trial, the results offer good news for people who are suffering especially severe PTSD and may be somewhat treatment resistant to exposure therapy.

"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," Dr. Kleine said.

In an accompanying commentary, Dr. John Krystal, the editor of Biological Psychiatry, noted that past brain research has provided evidence that people with PTSD may have limited neuroplasticity.

"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," he wrote.

D-cycloserine costs about $30 for 50mg or $120 for 250mg. It appears to have no common negative side effects for most people. A small risk of more serious side effects is possible, including various behavioral effects.

The study appeared online June 1 in the journal Biological Psychiatry. The research was funded by Stichting Achmea Slachtoffer en Samenleving and Vereniging tot Christelijke Verzorging van Geestes-en Zenuwzleken. The authors reported no conflicts of interest.

Review Date: 
June 8, 2012