Post-traumatic stress disorder

In a nutshell

PTSD arises when an overwhelming trauma impairs hippocampal contextualisation, leaving the memory stored as a raw, decontextualised amygdala-driven trace that can be triggered as a present-tense threat. Intrusive re-experiencing, hyperarousal and avoidance follow directly from this, and trauma-focused therapy works by allowing the memory to finally be recontextualised as past.

Classic presentation

Following a traumatic event, a patient develops vivid intrusive flashbacks and nightmares, avoids reminders of the trauma, and is hypervigilant and easily startled, with symptoms persisting beyond a month and impairing daily function.

Key points

• 1Flashbacks are involuntary re-experiencing, not ordinary remembering: they arise because the trauma memory bypassed normal hippocampal contextualisation.