Tryptophan and metabolites (serotonin and kynurenines) in posttraumatic stress disorder

It has become increasingly clear that trauma responses are defined less so by stressor-related factors and more so by individual-level factors, such as alterations in immune and inflammatory functioning. In this chapter, we begin with a summary and review of the prevalence, diagnostic characterization, and neurobiological etiology of Posttraumatic Stress Disorder (PTSD), presenting theory and research that describe the neuro-endocrinological, neurochemical, and neuroanatomical basis for PTSD. We then present evidence detailing the modulating and mediating roles of tryptophan derivatives (kynurenic acid, quinolinic acid, serotonin and melatonin) on the pathophysiology of disordered neurobiological and neuroinflammatory responses to fear/anxiety. Finally, we discuss both pharmacologic and non-pharmacologic therapeutic approaches that may be used in the treatment of PTSD.