Why long-term cocaine abuse can lead to brain abnormalities

Washington: A new study has revealed that long-term cocaine abuse may be associated with deficits in parts of the brain involved in monitoring and overseeing one's own behaviour.

The findings by researchers at the Icahn School of Medicine at Mount Sinai call into question the long-held clinical assumption that addicted individuals continue their compulsive drug use because of oppositional denial or lying, or because of careless minimization of their problems.

Using functional and structural MR imaging procedures, investigators were able to visualize abnormalities in error responding and gray matter integrity in the part of the brain known as the anterior cingulate cortex, which controls many cognitive functions, including recognizing and responding to mistakes.

Researchers sorted the addicted individuals by self-awareness, based on whether they were able to provide accurate reports of their own choice behaviour and through a written questionnaire that assessed emotional functioning. Results were compared against healthy controls and cocaine-addicted individuals who did not have these self-awareness deficits.

"Quantifiable functional and structural abnormalities in the brain were easy to see in the MRIs of cocaine-addicted individuals with impaired self-awareness," Rita Z. Goldstein, PhD, the study's senior author, said.

"These deficits were prominent even when we compared this subgroup of individuals with other cocaine-addicted individuals whose self-awareness was intact." Goldstein said.

More precisely, the anterior cingulate cortex was morphologically smaller and responded abnormally to errors in the cocaine-addicted individuals with impaired self-awareness.

The study was published in the journal JAMA Psychiatry.