From Biomarkers to New Treatments for Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) causes debilitating nightmares, flashbacks and anxiety stemming from a catastrophic, often life-threatening traumatic event. Originally described in soldiers exposed to the horrors of battle, PTSD is now recognized in civilian victims of assault, natural disasters and mass casualty events. Most people experiencing trauma do not develop PTSD, so understanding neurobiological mechanisms is crucial to predicting risk and developing targeted treatments. There have been many studies seeking to find biomarkers for PTSD, and their results have converged on several brain regions, molecular pathways and neuropsychological functions. In this review, we focus on selected findings about the glucocorticoid receptor (GR), the chaperone protein FKBP51 (FK506 binding protein 51), BDNF (brain-derived neurotrophic factor), fear memory reconsolidation and epigenetic regulation of gene expression in the hypothalamic-pituitary-adrenal (HPA) axis, amygdala and hippocampus. Together, these disparate aspects of brain function provide an emerging model for understanding the etiology and pathophysiology of PTSD. Avoidance of lethal threats is fundamental for survival, and this stringent evolutionary requirement has conserved many components of fear memory storage and behavioural response to danger. PTSD research can therefore rely on non-human animal model systems with better face and construct validity than most other psychiatric disorders. With this advantage, advances in PTSD biomarker identification are likely closer to clinical translation than in other mental illnesses. We attempt to highlight the most promising biomarkers that could be targeted by novel treatments and propose a map for future research work.