Chronic adversity may impair ability to cope with stress

People exposed to a lifetime of psychosocial adversity may have an impaired ability to produce the dopamine levels needed for coping with acutely stressful situations, according to a new UCL-led study. The findings, published in the journal eLife , may help explain why long-term exposure to psychological trauma and abuse increases the risk of mental illness and addiction. Lead author Dr Michael Bloomfield (UCL Psychiatry), an Excellence Fellow and leader of the Translational Psychiatry Research Group at UCL, said: "We already know that chronic psychosocial adversity can induce vulnerability to mental illnesses such as schizophrenia and depression. "What we're missing is a precise mechanistic understanding of how this risk is increased." To address this question, Dr Bloomfield and his colleagues used an imaging technique called positron emission tomography (PET) to compare the production of dopamine in 34 volunteers exposed to an acute stress. Half of the participants had a high lifetime exposure to psychosocial stress, while the other half had low exposure. All of them undertook the Montréal Imaging Stress Task, which involved receiving criticism as they tried to complete mental arithmetic. Two hours after this stress task, the participants were injected with small amounts of a radioactive tracer that allowed the scientists to view dopamine production in their brains using PET.