Chronic Adversity Impairs the Body’s Ability to Produce Dopamine: Study (dataset)
Wed, April 14, 2021

Chronic Adversity Impairs the Body’s Ability to Produce Dopamine: Study (dataset)

Chronic stress is the response to emotional pressure suffered for a prolonged period of time / Photo Credit: puhhha via 123rf

 

Long-term exposure to psychosocial adversity may impair the body’s ability to produce dopamine needed to cope with acute life stressors, a new study found.

 

Risk of long-term psychological abuse and trauma

The findings, which appeared in the journal eLife, explained that individuals who are exposed to long-term psychological abuse and trauma may have an increased risk of mental addiction and illness. To come up with such a conclusion, the team used positron emission tomography (PET), which is an imaging technique, to the dopamine production of 34 subjects, who were exposed to acute stress. Half of these participants had a lifetime exposure to psychosocial stress and the others had low exposure.

 

Using the Montreal Imaging Stress Task (MIST)

The participants also undertook the Montreal Imaging Stress Task (MIST). It consisted of various computerized mental arithmetic challenges including the social evaluation of threat components presented by the study investigator. The purpose of the test was to determine the effects of processing and perceiving psychosocial stress in the human brain. The subjects received criticism while they were trying to complete the mental arithmetic.

Small portions of radioactive tracer were then injected into the 34 subjects two hours after the MIST. A radioactive tracer is a chemical compound in which one or more atoms were replaced by a radioisotope to enable the scientists to peek into the brain’s dopamine production using PET as well. Results showed that participants with low exposure to chronic adversity had dopamine production that corresponded to the “degree of threat” perceived.

 

Individuals who are exposed to long-term psychological problems may have an increased risk of mental addiction and illness, study says / Photo Credit: Kurhan via 123rf

 

Perception of threat

 On the other hand, participants with high exposure to chronic adversity had an exaggerated perception of threat. This led the researchers to conclude that those participants already had impaired dopamine production. Dopamine is also known as the feel-good neurotransmitter or chemical that the body makes and the nervous system uses to send messages between the nerve cells. It plays an important role in how a person feels pleasure and is involved in the human ability to plan and think.

The sample characteristics and scan parameters they used to determine exposure to childhood adversity were parental loss, parental separation, going into foster care, and childhood sexual abuse. The parameters they used for adult adversity were the number of adverse life events over the last six months, their clinical scores, tobacco cigarette smokers in the last three months, and alcohol use in the last six months.

Dr. Michael AP Bloomfield from the Psychiatric Imaging Group and Imperial College of London’s Translational Psychiatry Research Group said that prior to their research, it has already been recognized in the medical field that chronic psychosocial adversity can make a person vulnerable to mental illnesses, including depression and schizophrenia. Yet, what is missing in the puzzle is the accurate mechanistic understanding as to how much risk is increased.

Bloomfield and colleagues also found that there are other physiological responses to stress that were impaired because of long-term exposure to chronic adversity. For instance, there was no increase in the cortisol levels and blood pressure of the high-adversity group compared to the low-adversity participants.

 

 

Dopaminergic dysfunction

Bloomfield cautioned though that their study alone cannot prove that chronic psychosocial stress can lead to substance abuse or mental illness by having lower dopamine levels. What their study pointed out is a plausible mechanism as to how chronic stress can increase a person’s risk of developing mental illness since the dopamine system of their brain is altered. They moreover emphasized that further work is needed so they can better understand how dopamine system changes caused by chronic adversity can cause vulnerability toward addiction and mental illness.

Even the US Department of Health and Human Services’ Office of the Administration for Children and Families has recognized that early adversity can lead to short- and long-term negative health effects. For example, it can disrupt the early brain development and compromise the functioning of the immune and nervous systems.

 

Chronic stress, anxiety disorder prevalence

Medical information platform Everyday Health conducted a survey in 2018 about chronic stress. It involved 6,700 Americans. It stated that 57 percent of their respondents said they were paralyzed by stress, 47 percent admitted they were invigorated by stress. Almost one-third of them said they visited a doctor about something stress-related. Over half of the women or 51 percent of them felt bad about their appearance weekly, 28 percent said their appearance was regularly causing them stress, and 34 percent of men also said that they felt bad about their appearance weekly.

Scientific online publication Our World in Data also highlighted the global prevalence of anxiety disorders among males and females in 2017. Among the countries it mentioned were: Vietnam with 1.45 percent share of male and 2.64 percent share of female suffering from anxiety disorders, Israel with 2.24 percent male and 3.86 female, Iran with 5.41 percent male and 8.39 percent female, Central Latin America with 2.15 percent male and 3.71 percent female, South Korea with 2.55 percent male and 5.02 percent female), UK with 3.48 percent male and 5.79 percent female, and the US with 4.76 percent male and 8.42 percent female.

 

 

There is no denying the extent of harm caused by chronic stress. It is best that everyone, not just in the healthcare industry, pay attention to it and find ways to address the problem.