LOS ANGELES—Multiple deployments during the long wars in Iraq and Afghanistan are impacting not only the men and women who have served overseas, but are also causing strain on their adolescent family members at home.

A new study from researchers at the University of Southern California School of Social Work finds a connection between increased drug and alcohol use among middle and high school students and deployments of either a military parent or sibling. The patterns of increased substance use were consistent for lifetime use, as well as in the most recent 30-day period.

“The potential for strain and the trauma associated with multiple deployments in the past 10 years of war seem to be driving this. People need to be aware that these experiences have an impact,” says Tamika Gilreath, an assistant professor in the USC School of Social Work and the lead author of “Alcohol, Tobacco, and Other Drug Use among Military and Non-military Connected Youth in the California Healthy Kids Survey,” appearing in the January issue of American Journal of Preventive Medicine.

The co-authors of the study are Julie Cederbaum and Ron Avi Astor, both of the USC School of Social Work; Rami Benbenishty of the Bar Ilan University School of Social Work in Jerusalem, Israel; and Diana Pineda and Hazel Atuel, also in the USC School of Social Work.

The data come from the California Healthy Kids Survey (CHKS), which asks students questions about health-related behaviors, school climate, violence behaviors and the use of tobacco, alcohol and drugs. In early 2011, more than 21,700 students also answered questions on a new supplementary “military module” survey, which allowed researchers for the first time to compare the experiences of military and non-military students in regular public schools.

The analysis, which focuses on a subsample of 14,149 seventh, ninth and eleventh graders in Southern California schools, also provides insight into how school-age children are affected by having a sibling in the military—a topic that has so far received minimal attention.

Gilreath and colleagues found that the prevalence of lifetime and recent drug use was higher among those with a sibling serving in the military than among those with a parent or no one serving.

“Everyone talks about the impact of parents, but no one talks about the impact of other close family members, such as a sibling,” Gilreath says. “If a sibling, as an adult, is using drugs and alcohol, a younger adolescent sibling might model the behavior.”

In addition, the heavy involvement of military reservists and National Guard members during this unprecedented time of war means that even though their families are exposed to the same stressors associated with deployment, they may not have access to the same support services as active duty members, the authors write. As military members transition to veteran status, their families may also lack resources to help them cope with the changes.

Gilreath and colleagues call for additional community- and school-based services designed to support military-connected students and their family members during deployments, as well as during periods of reintegration.

“Schools with a high density of students whose family members are already known to have deployed multiple times,” they write, “may decide to provide universal substance use education curricula and added internal referrals for parents and students.”