ELife: long term frustration can inhibit the production of dopamine

January 6, 2019 / biourn / - a recent study shows that people who suffer from social adversity for a long time in their life may not be able to produce enough dopamine to cope with acute stress The results, published in the latest issue of eLife, may help explain why long-term exposure to trauma and abuse increases the risk of mental illness and addiction The lead author, Dr Michael Bloomfield, head of the research group on translational psychiatry at University College London, UK, explained: "we already know that long-term social adversity can increase the risk of schizophrenia, depression and other mental diseases And we lack a precise understanding of how this risk increases " To solve this problem, Dr Bloomfield and his colleagues used an imaging technique called positron emission tomography (PET) to compare dopamine production in 34 volunteers exposed to acute stress Half of the participants had higher social and psychological stress in their lifetime, while the other half had lower stress All of them were given a task called "Montreal imaging pressure," which included criticism when they tried to do mental arithmetic Two hours after completing the stress task, the researchers injected participants with a small amount of radioactive tracer, allowing scientists to use pet to observe dopamine production in the brain Scans showed that in people who had been chronically stressed for a long time, dopamine production was directly proportional to the perceived threat However, people who have been in chronic adversity for a long time have not enough dopamine production, but also "exaggerated" the perception of threat "This study does not show that chronic psychological stress necessarily reduces dopamine levels," Dr Bloomfield said But we offer a reasonable mechanism for how chronic stress increases the risk of mental illness by altering the dopamine system in the brain " Information source: Michael AP Bloomfield, Robert A McCutcheon, Matthew Kempton, Tom P Freeman, Oliver Howes The effects of psychosocial stress on dopaminergic function and the acute stress response ELife, 2019; 8 doi: 10.7554/elife.46797