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Substance abuse is associated with lower brain volume in women but not in men

University of Colorado Denver

AURORA, Colo. (July 14, 2015) - A new study by a team of researchers at the University of Colorado School of Medicine on the Anschutz Medical Campus found that long-term stimulant abuse had more significant effects on brain volume in women compared with men.

For the study, Jody Tanabe, MD, professor of radiology, and her colleagues sought to determine how the brains of people previously dependent on stimulants were different from the brains of healthy people. The results were published online in the journal Radiology.

"We specifically wanted to determine how these brain effects differed by gender," said Tanabe, who is also vice chair of research in the Department of Radiology.

The researchers analyzed structural brain magnetic resonance imaging 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 people (28 women and 40 men) who were similar in age and were not previously dependent on those drugs.

"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 women who were former stimulant abusers showed significant loss of gray matter volume in their brains, while men who were former stimulant abusers demonstrated no significant brain differences compared to their healthy counterparts.

The researchers looked at how these brain volume differences were related to behaviors. In women who were previously dependent on stimulants, there were vast changes in brain structures that are important for decision making, emotion, reward-processing and habit formation.

"The gray matter volumes in women who had been stimulant dependent correlated with more impulsivity, greater behavioral tendencies to approach to reward, and also more severe drug use," Tanabe said. "In contrast, all men and healthy women did not show such correlations."

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

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This study was supported by grants from the National Institute on Drug Abuse. Other authors from the University of Colorado Anschutz Medical Campus were Michael Regner, MD, Manish Dalwani, MS, Dorothy Yamamoto, PhD, Robert Perry, MD, Joseph Sakai, MD, and Justin Honce, MD.

About the University of Colorado School of Medicine

Faculty at the University of Colorado School of Medicine work to advance science and improve care. These faculty members include physicians, educators and scientists at University of Colorado Health, Children's Hospital Colorado, Denver Health, National Jewish Health, and the Denver Veterans Affairs Medical Center. The school is located on the Anschutz Medical Campus, one of four campuses in the University of Colorado system. To learn more about the medical school's care, education, research and community engagement, visit its web site.

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