title: Posttraumatic stress disorder.
abstract: OBJECTIVE
  The objectives of this article are to update the reader on the current definition and diagnostic assessment of posttraumatic stress disorder (PTSD) and to describe its clinical characteristics, discuss its epidemiology and pathophysiologic aspects, as well as to summarize the current therapeutic options for PTSD.
  
  
  RESULTS
  The new nomenclature of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) includes 20 PTSD symptoms clustered into four symptomatic domains: intrusive symptoms, active avoidance, disturbed emotional states, and alterations of arousal and reactivity. Diagnostic structured interviews and severity scales have been updated in order to address this recent revision. It is also recognized that the neural circuits whose disruption might explain the genesis of PTSD symptoms, although overlapping, may be different between these four domains, a fact that may inform new biologically based phenotypes with prognostic and therapeutic implications.During the past years, there has been active research into the different factors influencing vulnerability and resilience to stress, including the effect of genetic and epigenetic variations. The neural circuits involved in the processing of threatening stimuli have been studied in patients with PTSD through paradigms inspired in animal research. These studies suggest that patients with PTSD have difficulty discriminating danger from safety cues and have problems suppressing fear in the presence of safety cues. Functional MRI (fMRI) studies suggest that the increased amygdala activation observed in these patients results from abnormal modulatory input from the ventromedial prefrontal cortex. Structural brain abnormalities, on the other hand, have been more consistently identified in the hippocampus.Prolonged exposure therapy and cognitive reprocessing are the interventions that have the more extensive validation of their psychotherapeutic efficacy. Medications are modestly more effective than placebo to treat PTSD symptoms, and selective serotonin reuptake inhibitors (SSRIs) are considered a safe initial choice. Use of combined strategies including pharmacologic modulation of fear processing is an area of active research.
  
  
  CONCLUSIONS
  PTSD is a frequent psychopathologic condition with a lifetime prevalence that is close to 10%. In the past few years, there have been significant advances in the definition of the disorder, in elucidating the neurobiology of vulnerability and resilience, and in developing new treatment alternatives.
authors.forename: Ricardo E
authors.initials: RE
authors.lastname: Jorge
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D005239:Fear; D005820:Genetic Testing; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D008297:Male; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D012307:Risk Factors; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology* / Q000628:therapy*