Dr. Alexander Neumeister, Department of Psychiatry, Mount Sinai School of Medicine, tracks the response of stress on the serotonin system in the brain and discovers that people who experience trauma early in life have a lower number of serotonin 1B receptors than healthy controls.

Dr. Neumeister represents a generation of researchers that brings together biology and psychology to identify underlying causes and improve treatments of brain and behavior disorders. With a NARSAD Independent Investigator grant in addition to a Merit award from the Department of Veterans Affairs (VA), a grant from the VA Center on PTSD and two grants from National Institutes of Health, Dr. Neumeister undertook the largest Positron Emission Tomography (PET) study to date of individuals with PTSD to understand how stress affects their brains.

PET brain imaging technology allowed Dr. Neumeister and his team to take two-hour movies of how the brain works. Of specific interest to Dr. Neumeister and his team are serotonin type-1B receptors. These receptors influence various biological and neurological processes, such as aggression, anxiety, cognition, memory and mood. Dr. Neumeister’s study included 96 participants – 49 individuals with PTSD, 20 individuals exposed to early trauma without PTSD and 27 healthy “controls” (participants not traumatized). Of the patients experiencing trauma, each lived through their first trauma at 15.

A main finding of Dr. Neumeister’s study was that the serotonin system is involved in stress response and people who experience trauma earlier in life have a lower number of 1B receptors than healthy controls. Additionally, the earlier someone is traumatized, their PTSD symptoms are more severe and there is a greater occurrence of PTSD being accompanied by another disorder like major depression. This is the first time a neurobiological correlation in brain function and behavioral alterations in PTSD has been made, proof that the brains of people with PTSD work differently.

“Some people think, ‘What does PTSD have to do with the brain?’” Dr. Neumeister said. “This study shows that the trauma people experience affects the brain.” His team shows that the trauma itself and not the symptoms are related to neurobiological messages.

Dr. Neumeister’s goal is ultimately to identify pathological processes and find targets for treatments. The efficacy of the only class of drugs – SSRIs (selective serotonin reuptake inhibitors) – approved for treating PTSD is limited, Dr. Neumeister explained.