Conversely, overactivity of the prefrontal cortex could lead to a "freeze" response and emotional detachment.
Even minor stresses may then trigger the "fight or flight" response, which leads to activation of the brain's adrenergic circuitry as well as increased heart rate, sweating, rapid breathing, tremors, and other symptoms of hyperarousal in patients with PTSD.
The HPA system and other components of the human stress response are also mobilized in response to threat or other stressful stimuli (13).
It is vital for the clinician to question the level of evidence supporting the medications being prescribed for PTSD, because there are a variety of influences on prescribing, including marketing, patient preferences, and clinical custom, all of which can be inconsistent with the current evidence base.
The current evidence base for PTSD psychopharmacology is strongest for the selective serotonin reuptake inhibitors (SSRIs), and currently only sertraline (Zoloft) and paroxetine (Paxil) are approved by the Food and Drug Administration (FDA) for PTSD (1, 2).
A deficiency in amygdala serotonin transport has been identified in some individuals with PTSD (15).