There
are a wide range of basic, clinical, and genetic studies of
PTSD. In addition, NIMH has a special funding mechanism, called
RAPID Grants, that allows researchers to immediately visit the
scenes of disasters, such as plane crashes or floods and hurricanes,
to study the acute effects of the event and the effectiveness
of early intervention. Studies in animals and humans have focused
on pinpointing the specific brain areas and circuits involved
in anxiety and fear, which are important for understanding anxiety
disorders such as PTSD. Fear, an emotion that evolved to deal
with danger, causes an automatic, rapid protective response
in many systems of the body. It has been found that the body's
fear response is coordinated by a small structure deep inside
the brain, called the amygdala. Though the amygdale is relatively
small, it is a very complicated structure, and recent research
suggests that different anxiety disorders may be associated
with abnormal activation of the amygdala.
The following are also recent research findings:
In brain imaging studies, researchers have found that the hippocampus-a
part of the brain critical to memory and emotion-appears to
be different in cases of PTSD. Scientists are investigating
whether this is related to short-term memory problems. Changes
in the hippocampus are thought to be responsible for intrusive
memories and flashbacks that occur in people with this disorder.
People with PTSD tend to have abnormal levels of key hormones
involved in response to stress. Some studies have shown that
cortisol levels are lower than normal and epinephrine and norepinephrine
are higher than normal.
When people are in danger, they produce high levels of natural
opiates, which can temporarily mask pain. Scientists have found
that people with PTSD continue to produce those higher levels
even after the danger has passed; this may lead to the blunted
emotions associated with the condition. Research to understand
the neurotransmitter systems involved in memories of emotionally
charged events may lead to discovery of medications or psychosocial
interventions that, if given early, could block the development
of PTSD symptoms.
|
