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
News just in — eLife, has now published the results of some interesting research on mental health, which could help explain why people who suffer chronic exposure to psychological abuse and trauma, have a heightened risk of suffering from addiction and mental health issues.
Taking a Closer Look
The findings show that: “exposure to chronic adversity in childhood and adulthood can lead to a dampened physiological response to acute stress, and an exaggerated threat perception. Indeed, The University College of London Translational Psychiatry Research Group’s leader, Dr Michael Bloomfield, noted: “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”.
Taking a Step Toward Gaining an Understanding
In order to achieve this, 34 people volunteered to take part in the study. Bloomfield and his team then used a PET imaging machine, so they could make a comparison in the volunteers’ dopamine production levels when they were confronted by 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”.
Once the stress test was completed, two hours later, the subjects were injected with tiny quantities of a radioactive tracer. This enabled the researchers to ascertain the dopamine production in the participants’ brains via PET scans. The latter indicated that: “in those with low exposure to chronic adversity, dopamine production was proportional to the degree of threat that the person perceived”.
Individuals Who Had Suffered Chronic Adversity Did Not Fare Well
The participants who had experienced high exposure to chronic adversity in their lifetimes, had an exaggerated perception of the threat, whilst their dopamine production was impaired. Moreover, the scientists determined that their other physiological reactions to stress were also impaired. For instance, when compared to the low-adversity group, the normal subjects’ cortisol and blood pressure levels did not rise as much.
Remarking cautiously on the results, the senior study author, Professor of Molecular Psychiatry at King’s College London, and the MRC London Institute of Medical Sciences, Oliver Howes, stated: “This study can’t prove that chronic psychosocial stress causes mental illness or substance abuse later in life by lowering dopamine levels”. To which, Bloomfield added: “But we have provided a plausible mechanism for how chronic stress may increase the risk of mental illnesses by altering the brain’s dopamine system”.
Clearly, this was just a small study, and more research is needed in order to better understand how adversity in life can negatively affects the dopamine system, which can potentially result in people’s vulnerability toward addiction and mental illnesses.