Post-traumatic stress disorder (PTSD) is associated with lowered levels of a neurotransmitter in a brain region that plays a role in panic and stress, researchers reported.  In a cohort study, positron emission tomography also linked the availability of the molecule, norepinephrine transporter or NET, to one of the five facets of the syndrome, according to Alexander Neumeister, MD, of NYU School of Medicine in New York City, and colleagues.  {read more here}