[Treatment of posttraumatic stress disorder and extinction learning of traumatic memory].

Posttraumatic stress disorder (PTSD) is a debilitating psychological condition that develops following exposure to a traumatic event. The characteristic symptoms of PTSD are re-experience, avoidance, psychic numbing and hyper-arousal. The biological PTSD literature has been dramatically growing over the past three decades. PTSD symptoms related to re-experiencing the traumatic event may be conceptualized within a fear conditioning framework. Recent findings suggest that PTSD is associated with a failure of extinction learning of an acquired fear response. A fear-circuit model of PTSD posits that vmPFC fails to inhibit the amygdala, which has a crucial role in fear learning. Exposure therapy currently has the largest number of randomized clinical trials demonstrating its efficacy, and is recommended with substantial clinical confidence in treatment guidelines for PTSD. The efficacy of Prolonged Exposure (PE) was also shown for Japanese PTSD patients in a randomized controlled trial (Asukai et al., 2010). The emotional processing theory that accounts for the treatment mechanism of PE may be consistent with the hypothesis of a neurobiological mechanism in PTSD. D-cycloserine (DCS), an NMDA partial agonist, has been shown to facilitate extinction learning in animals and humans. Clinically, DCS has been shown to be a promising augmentation to PE, particularly for those who need longer treatment.