of drug dependence typically have deficits
in self-control. But, did you know
that the brain vulnerabilities had a family origin
that may pave the way for addiction
to develop from occasional use?
A study conducted by Dr. Karen Ersche, Department of Psychiatry, University of Cambridge, England, and published in Science, reveals that one sibling who is addicted to drugs, and the other who is not, have similar brain abnormalities.
These abnormalities come from the fronto-striatal systems, an area of the brain that is vital for aiding people in exhibiting self control. (Ersche K, Jones P, Williams G, Turton A, Robbins T, Bullmore E. "Abnormal Brain Structure Implicated in Stimulant Drug Addiction." Science 3 February 2012:Vol. 335 no. 6068 pp. 601-604.)
Dr. Ersche and her researchers compared 50 healthy participants' brain scans with the brain scans of 50 pairs of siblings. In the pairs of siblings, one was addicted to cocaine, and the other sibling did not use alcohol or drugs at all. The siblings, all with a family history of substance use, grew up in abusive homes.
The brain scans revealed abnormalities among both the addicts and their siblings in the prefrontal cortex, an area of the brain that’s responsible for self-control. Also, the putamen, a structure involved in forming habits, tended to be larger in drug users and their siblings, while structures in the brain that manage responses to cravings tended to be smaller.
This research should help people understand why it is more likely for people who have a history of drug abuse in their families to develop the addiction, than those without any family history of drug addiction or abuse.
The findings determined that the person addicted to the cocaine and their sibling both possessed the same brain abnormalities in an area of the brain called the frontal-striatal system, yet somehow some siblings of addicts were able to resist addiction.
Ersche says, “It has long been known that not everyone
who takes drugs becomes addicted, and that people
at risk of drug dependence typically have deficits in self-control.
"Our findings now shed light on why the risk
of becoming addicted to drugs is increased in people
with a family history of drug or alcohol dependence:
parts of their brains underlying self-control abilities work less efficiently.
The use of addictive drugs such as cocaine
further exacerbates this problem,
paving the way for addiction to develop from occasional use.”
The Huge Question
"Presumably, the siblings must have some other resilience factors
that counteract the familial vulnerability to drug dependence," says Ersche.
Of course, the most important question remains unanswered: "How were the siblings of the addicts able to resist addiction?" Although biologically predisposed to develop dependency, these people do not. Science must engage itself in further study to find answers to this nagging question.
Interventions that focus on improved self-control is one avenue researchers are exploring. Using information about why siblings didn’t succumb to compulsive or addictive behavior is another important key in battling addiction.
A critical next step for substance abuse researchers is understanding what causes a person to spiral out of control. Ersche believes if they are able to identify high-risk people and utilize early intervention that reinforces self-control, addiction could stop attacking a family tree.
"Our findings now shed light
on why the risk of becoming addicted
to drugs such as cocaine further exacerbates this problem,