Anxiety and fear in PTSD

Abstract Hallmark symptoms of PTSD include the expression of fear or anxiety as evidenced by reexperiencing of the traumatic event, distress upon reminders of the trauma, avoidance of trauma reminders, persistent negative cognitions about oneself and ongoing threat, and hyperarousal. These symptoms occur despite the absence of or disproportionate to the actual danger posed by the environment. Associative learning models of PTSD posit that classical conditioning and impaired fear extinction principles are at the core of the development, maintenance, and amelioration of PTSD symptoms. In this chapter, basic neurobiological understandings of fear are reviewed, highlighting brain regions associated with fear conditioning and extinction processes in PTSD. The role of sensitivity to threat, specifically anxiety sensitivity and attentional biases toward threat, in fear responding and PTSD symptomatology is then reviewed. Overgeneralization of conditioned fear responses and excessive avoidance of fear-related stimuli also contribute to the development and maintenance of PTSD symptoms. Finally, impaired fear inhibition learning in PTSD is reviewed, examining impairments in safety signal learning and fear extinction as core processes impeding resilience and recovery after trauma exposure.