Will an antibiotic help treat PTSD?

Researchers are exploring the possibility of potentially treating post-traumatic stress disorder (PTSD) with an antibiotic after a specially designed trial returned promising results. The study, led by British and Swiss scientists, involved 76 healthy volunteers and a common antibiotic called doxycycline.

During the trial, volunteers were given either the antibiotic or a placebo pill, with those who received doxycycline reporting a 60 percent lower fear response than those who were not. Researchers said the pill works to disrupt the formation of negative thoughts and fears in the brain by blocking certain proteins outside of nerve cells which are needed to form memories.


“We have demonstrated a proof-of-principle for an entirely new treatment strategy for PTSD,” Dominik Bach, a professor at University College London and the University of Zurich, and co-leader of the research team, told Reuters.

To reach these conclusions, volunteers were given either the antibiotic or placebo and placed in front of a computer that would flash either blue or red. One of the colors was associated with a 50 percent chance of receiving a painful electric shock. After 160 flashes with color in random order, participants were aware of which color was associated with the shock, Reuters reported. A week later, the experiment was repeated with no medication, and the shocks were replaced by loud sounds.


Researchers measured fear responses by tracking eye blinks and calculated fear memory by subtracting the baseline startle response from the response to the sound when the ‘bad’ color appeared, Reuters reported. The fear response was calculated to be 60 percent lower in patients that received doxycycline, but other cognitive measures, like sensory memory and attention, were not affected, according to the report.

“When we talk about reducing fear memory, we’re not talking about deleting the memory of what actually happened,” Bach told Reuters. “The participants may not forget that they received a shock when the screen was red, but they ‘forget’ to be instinctively scared when they next see a red screen. Learning to fear threats is an important ability … helping us to avoid dangers. (But) over-prediction of threat can cause tremendous suffering and distress in anxiety disorders such as PTSD.”

The researchers plan to explore doxycycline’s potential effects further to develop additional ways to treat PTSD.

Reuters contributed to this report.