Stimulant Abuse Appears to Alter Brain Volume In Women

A study published last month in the journal Radiology has found that long-term stimulant abuse is negatively correlated with gray matter volume in the brains of women, but not in men—even after a prolonged period of abstinence.

University of Colorado Denver School of Medicine

“Gray matter, which consists of the cell bodies of neurons, is important because it is where signals are generated that give us the ability to think, move, and behave,” said the study’s senior author, Jody Tanabe, M.D., a professor of psychiatry and radiology at the University of Colorado Denver School of Medicine. Previous studies have showed that some brain structures in men and women differ, which may contribute to behavioral pattern differences between the two groups, including those related to substance use disorders, she explained.

“Compared with men, women tend to begin cocaine or amphetamine use at an earlier age, show accelerated escalation of drug use, report more difficulty quitting, and, upon seeking treatment, report using larger quantities of these drugs,” Tanabe told Psychiatric News. Comparing the impact of long-term stimulant use in men versus women may offer insight into the biological mechanisms underpinning these differences.

For the study, the researchers analyzed structural brain magnetic resonance imaging exams of 127 men and women; they included 59 people (28 women and 31 men) who were previously dependent on cocaine, amphetamines, and/or methamphetamine for an average of 15.7 years, and 68 people (28 women and 40 men) with no history of stimulant drug dependence. Participants with past stimulant addictions had been abstinent an average of 14 months at the time of the study.

The data showed that women who were previously dependent on stimulants had significantly less gray matter volume in widespread brain regions (including the frontal and temporal lobes, and limbic regions) than nondependent women; no differences in gray matter volume were observed between male control subjects and men with stimulant dependence. Lower gray matter volumes in the nucleus accumbens of women with a history of stimulant dependency were associated with the severity of past drug abuse, measured by the Composite International Diagnostic Interview Substance Abuse Module. Lower volumes in the frontal and temporal lobes were associated with elevated impulsivity and behavioral tendencies to seek reward—as measured by the Barratt Impulsiveness Scale and Behavioral Activation System questionnaire. Similar differences were not seen in men or women without a history of stimulant dependence.

“These differences between the sexes could reflect a greater neuroanatomic endophenotype in women that predisposes them to stimulant dependence or a vulnerability to morphologic changes that result from stimulant dependence,” the researchers noted.

“We do not know the exact reason but there can be several possibilities for the study’s outcome,” said Tanabe, who explained to Psychiatric News that she and her colleagues next plan to examine whether there are differences between subcortical structures in the brains of men and women with a history of stimulant drug use.

Tanabe concluded that she hopes the results from the current study will lead to more investigation into sex differences in substance dependence and, thus, more effective clinical treatment and recovery plans.

The study was funded by the National Institutes of Health. ■