Post- traumatic stress disorder (PTSD) is a mental health condition that develops in response to experiencing or witnessing a distressing event involving the threat of death or extreme bodily harm. Examples of traumatic events that can trigger PTSD include sexual assault , physical violence, and military combat. PTSD can also occur in the wake of a motor vehicle accident, a natural disaster (e.g., fire, earthquake, flood), a medical emergency (e.g., having an anaphylactic reaction), or any sudde
PTSD and the Human Brain
Researchers are intensely investigating what trauma does to the brain, in the hope of developing effective treatments for PTSD. Scientists know that in PTSD, the stress circuitry in the brain goes awry, disrupting communication between several brain centers. These include the amygdala, which normally monitors incoming perceptions and red-flags threats, putting systems on high alert and setting off the stress response; the prefrontal cortex, or executive control center of the brain, which normally senses when a threat is over and dampens amygdala activity; and the hippocampus, where memories are stored and retrieved.
Scientists find that in PTSD, the prefrontal cortex is underactivated, and the amygdala is overactivated. There is evidence that a core problem lies in the connections between individual nerve cells, or synapses; there is a deficit in connectivity, limiting communication between nerve cells. As a result, individuals with PTSD lose psychological flexibility: They stay stuck in an over-the-top response pattern, and their memories resist the modification that normally occurs over time.
PTSD is a whole-brain disorder that involves the brain circuits of fear, stress, and anxiety . The amygdala (which sets off the fight-or-flight response) becomes hyperactive . Meanwhile, the prefrontal cortex (the CEO, or executive functioning center of the brain) grows sluggish or lacks sufficient neural connections with the amygdala to calm down the fear response. In people with PTSD, the hippocampus (the verbal memory center) tends to be smaller than normal and yet more active in response to perceived threats.
In response to an overactive amygdala and underactive prefrontal cortex, the brain releases large amounts of norepinephrine in the presence of perceived danger. This can affect brain functioning in several ways, leading to hyperarousal, hypervigilance, and increased wakefulness and disrupted sleep. PTSD sufferers may also find that when they are emotionally aroused, they have little control over their reactive anger and impulsive behaviors. The weight of negative emotions such as fear and anger can diminish positive feelings and create problems at work and in personal relationships.
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