Is posttraumatic stress disorder a stress‐induced fear circuitry disorder?

Abstract

Neuroimaging studies of posttraumatic stress disorder (PTSD) have reported functional abnormalities in brain regions involved in fear conditioning, extinction, and emotion regulation. These findings have prompted researchers to consider whether PTSD can be characterized as a stress-induced fear circuitry disorder. In this review, the authors summarize the results of functional neuroimaging studies and conclude that there is a strong argument for characterizing PTSD as a stress-induced fear circuitry disorder. They also acknowledge that (a) fear is not the only emotion associated with PTSD, (b) a state of fear is not required to observe fear-circuitry abnormalities in this disorder, and (c) not all functional abnormalities in PTSD are related to fear circuitry. Implications for future diagnostic classifications are discussed.

The neurobiology of posttraumatic stress disorder: Dysfunction in the prefrontal-amygdala circuit?

“…This approach is based on the idea that PTSD may be generally linked to changes in the processing of emotional stimuli and not specifically to trauma-related stimuli. This view widens the possibility that PTSD involves not only fear conditioning, which has indeed been debated in the literature (Koenigs & Grafman, 2009;Shin & Handwerger, 2009).…”

“…To determine the risk factors for developing PTSD, Shin and Handwerger (2009) recently studied monozygotic twins who differed in their exposure to the Vietnam War. Veterans with PTSD and their twin brothers who were not exposed to war exhibited higher rates of cerebral glucose metabolism in the dorsal anterior/ midcingulate cortices compared with those without PTSD and their respective twins.…”

Pharmacotherapy for posttraumatic stress disorder: Review with clinical applications

“…A number of physiological differences are reported in persons with PTSD, including disturbances in neurological integration of the fear circuitry [34], reduced serotoninergic modulation of the fear response in key areas such as the amygdala [35], and dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Abnormal HPA axis function is often expressed by lower baseline cortisol levels and excessive suppression of the HPA axis by exogenous steroids [36][37][38].…”

Emotional Memory and Posttraumatic Stress Disorder: A Preliminary Neuropsychological Study in Female Victims of Domestic Violence

“…PTSD is considered a disorder of emotional memory that involves brain function abnormalities related to fear conditioning, fear memory extinction, involuntary retrieval (flashbacks and intrusions) and context-independent fear [6][7][8][9][10]. Numerous neuroimaging studies have reported diminished activation in the hippocampus in PTSD [11][12][13] or significant hippocampal volume reduction in PTSD patients [14][15].…”

“…Numerous neuroimaging studies have reported diminished activation in the hippocampus in PTSD [11][12][13] or significant hippocampal volume reduction in PTSD patients [14][15]. Similarly, the neurocircuitry models of PTSD posit that both hippocampal dysfunction and amygdala hyperactivity are related to the performance of emotional memory in PTSD [8,16]. If the hippocampus is not fully functional and does not form conscious emotional memories during a traumatic situation, it will form unconscious emotional memories that are supported by the amygdala [17].…”