Common antibiotic may help to prevent or treat PTSD

The common antibiotic doxycycline can disrupt the formation of negative associations in the brain, according to new research from UCL and the University of Zurich. The study, published in Molecular Psychiatry, was a pre-registered, placebo-controlled, double-blind randomised controlled trial in 76 healthy volunteers. In the first session, participants were given either doxycycline or a placebo and learnt to associate a certain colour with an electric shock. A week later they were shown the colours again, accompanied by a loud sound but no shocks, and their fear responses were measured. The fear response was 60% lower in participants who had doxycycline in the first session compared to those who had the placebo, suggesting that the fear memory was significantly suppressed by the drug. Other cognitive measures including sensory memory and attention were not affected. "When we talk about reducing fear memory, we are not talking about deleting the memory of what actually happened," explains lead author Professor Dominik Bach (UCL Wellcome Centre for Neuroimaging, Max Planck UCL Centre for Computational Psychiatry and Ageing Research and University of Zurich Division of Clinical Psychiatry Research).