Some child abuse victims' brains protect them from addictions - study

A mechanism in the brain tries to protect itself from addiction if the person was exposed to childhood abuse, a new study has found.

The peer-reviewed study, published in Molecular Psychiatry, has found that the brain can provide high levels of a cannabinoid substance to protect individuals from developing addiction.

Previous research has shown that individuals who experienced childhood maltreatment are three times as likely to develop drug or alcohol addiction. However, this data shows only a fragment of the issue.

“There’s been a lot of focus on addiction as a disease driven by a search for pleasure effects and euphoria, but for many it has more to do with the drugs’ ability to suppress negative feelings, stress sensitivity, anxiety and low mood,” explains Markus Heilig, professor and director of the Center for Social and Affective Neuroscience, CSAN, at Linköping University and consultant at the Psychiatric Clinic of the University Hospital in Linköping. “Based on this, we and other researchers have had a theory that if affected in childhood, the function of the brain’s distress systems is altered, and that this may contribute to addiction risk in adulthood.”

The role of Endocannabinoids

Endocannabinoids is a cannabis-like substance which is naturally produced by the body. Research suggests that humans have developed this substance to act a buffer to stress.

Researchers divided 100 participants into four groups: Individuals that had been exposed to childhood maltreatment and had developed an addiction (group 1), individuals that had been exposed but had not developed an addiction (group 2), individuals that had not been exposed to childhood maltreatment but had developed an addiction (group 3), and individuals who had neither been exposed nor developed an addiction (group 4).

Participants from groups 1 and 2 were identified as having experienced maltreatment based on exposure to physical and/or sexual abuse and/or severe neglect referred by the child protective services.

The researchers carried out blood tests on the participants, to measure their endocannabinoid levels, an MRI exam and several stress tests.

Researchers found that members of group 2 had increased function of the endocannabinoid system and different brain activity. The researchers were also surprised to find that this group differed the most from control group 4.

Group 2 had high levels of brain activity in three parts of the brain. The activity increased in the brain network that focuses attention and cognitive abilities on what is important at the moment and modifies individuals’ behavior according to the situation at hand and the frontal lobe which is associated with emotional regulation.

­“Increased activity in certain areas of the brain in the resilient group, which had not developed an addiction despite childhood maltreatment, may be linked to a more adaptive way of reacting to emotional social information. We can see that also in a resting state, they show increased communication between the frontal lobes and other parts of the brain, which could indicate that this group has better emotional regulation,” says Irene Perini, staff scientist at CSAN at Linköping University.

The researchers shared that future studies were needed to discover whether group 2 had a high endocannabinoid system function from the outset or if the system was activated in response to stress.