Young women who have experienced traumatic events are more likely to become alcohol dependent than those who have not, according to researchers at Washington University School of Medicine in St. Louis and the Midwest Alcoholism Research Center (MARC), which is housed in the Department of Psychiatry at the School of Medicine.
The MARC involves collaborations among Washington University alcoholism researchers and scientists at the University of Iowa, the University of Missouri-Columbia, the Veterans Administration Palo Alto Health Care System, Arizona State University and Queensland Institute of Medical Research in Australia.
The center is preparing to host the 11th Annual Guze Symposium on Alcoholism, which this year will focus on Trauma and Alcoholism, Findings from studies published in the journals Psychological Medicine and the Journal of Studies on Alcohol and Drugs suggest that trauma is an important risk factor for alcohol problems in women.
The research team, led by Carolyn E. Sartor, PhD, research instructor in psychiatry at the School of Medicine, studied 3,768 female twins ages 18 to 29 to measure the influence of genes and environment in post-traumatic stress disorder (PTSD) and alcohol dependence.
They asked participants about exposure to a range of traumatic events, including assaultive traumas such as childhood physical and sexual abuse and rape as well as non-assaultive events such fire, flood, natural disasters, accidents and witnessing someone else being seriously injured or killed.
The results showed elevated rates of alcohol dependence in women with PTSD. One in three of the women suffering from PTSD developed alcohol dependence, but it was not just women who developed PTSD after experiencing a traumatic event who were at higher risk for becoming alcohol dependent. Although these women had the highest rates of alcohol dependence, women who experienced trauma but did not develop PTSD had double the rates of alcohol dependence of women with no history of trauma: 14.8 percent to 7.3 percent.
“After we accounted for risk factors common to PTSD and alcohol dependence, such as depression, we did not find a significant difference in alcoholism risk between the women who developed PTSD and those who did not develop PTSD after experiencing a traumatic event,” Sartor says. “Our evidence suggests that the increased risk is attributable to trauma, not specifically to PTSD.”
Previous research has demonstrated that between 10 percent and 13 percent of women suffer from PTSD at some time in their lives. That’s about twice the rate of PTSD in men. Women with the greatest risk are those who have been sexually assaulted. Between 30 percent and 50 percent of sexual assault victims develop the disorder.
In a separate study, Sartor and her colleagues examined the role of genetic and environmental influences on trauma, PTSD and alcohol dependence.
“We found evidence that some of the genetic factors that contribute to PTSD also contribute to alcohol dependence,” she explains. “That means women with a family history of either PTSD or alcohol-related problems are more susceptible to both disorders.”
By studying twins, the researchers were able to get ideas about genetic contributions to how the women responded to environmental influences, such as trauma. Identical twins share 100 percent of their genetic material, and fraternal twins share about half. So when identical twin pairs are found to be more similar in a particular type of behavior than fraternal twin pairs, it suggests genes are playing a role in that behavior.
The researchers found that genetic influences accounted for 72 percent of the risk for developing PTSD following a traumatic event. For alcohol dependence, genes accounted for 71 percent of the risk.
Experts in the fields of genetics, alcoholism and trauma will be presenting many of the latest findings in the field at the daylong Guze Symposium on Alcoholism on Thursday, Feb. 17 at the Eric P. Newman Education Center at 320 South Euclid, St. Louis, MO 63110. For more information, visit the MARC’s website at www.alcoholdependence.org.
Sartor CE, McCutcheon VV, Pommer NE, Nelson EC, Duncan AE, Waldron M, Bucholz KK, Madden PAF, Heath AC. Posttraumatic stress disorder and alcohol dependence in young women, Journal of Studies on Alcohol and Drugs, vol. 71(6), Nov., 2010. pp. 810-818.
Sartor CE, McCutcheon VV, Pommer NE, Nelson EC, Grant JD, Duncan AE, Waldron M, Bucholz KK, Madden PAF, Heath AC. Common genetic and environmental contributions to post-traumatic stress disorder and alcohol dependence in young women, Psychological Medicine, published online in Nov., 2010. DOI:10.1017/S0033291710002072
This work was supported by grants from the National Institute on Alcohol Abuse and Alcoholism, the National Institute on Child Health and Human Development and the National Institute on Drug Abuse of the National Institutes of Health.
Washington University School of Medicine’s 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.