Study shows drug abuse reduces grey matter in women

Stimulant drug abuse may have long-term effects on brain volume in women, a new study has warned. Brain structures involved in reward, learning and executive control showed vast changes even after a prolonged period of abstinence from drug use, researchers said.

"We found that after an average of 13.5 months of abstinence, women who were previously dependent on stimulants had significantly less grey matter volume in several brain areas compared to healthy women," said senior author Jody Tanabe, Neuroradiology Section Chief at the University of Colorado Denver School of Medicine. "These brain areas are important for decision making, emotion, reward processing and habit formation," Tanabe said.

For the study, the researchers sought to determine how the brains of people previously dependent on stimulants differed from the brains of healthy people. "We specifically wanted to determine how these brain effects differed by gender," Tanabe said. The researchers analysed structural brain magnetic resonance imaging (MRI) exams in 127 men and women, including 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 healthy people (28 women and 40 men) who were similar in age and gender.

The MRI results showed that after an average of 13.5 months of abstinence, women who were previously dependent on stimulants had significantly less grey matter volume in frontal, limbic and temporal regions of the brain.
"While the women previously dependent on stimulants demonstrated widespread brain differences when compared to their healthy control counterparts, the men demonstrated no significant brain differences," Tanabe said.
The researchers also looked at how these brain volume differences were related to behaviours. They found that lower regional grey matter volumes correlated with behavioural tendencies to seek reward and novelty. "Lower grey matter volumes in women who had been stimulant dependent were associated with more impulsivity, greater behavioural approach to reward, and also more severe drug use," Tanabe said. "In contrast, all men and healthy women did not show such correlations," Tanabe said.

According to Tanabe, the results may provide a clue to the biological processes underlying the clinical course of stimulant abuse in men and women. "Compared to 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," she said. "We hope that our findings will lead to further investigation into gender differences in substance dependence and, thus, more effective treatments," Tanabe said The study was published in the journal Radiology.
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