Researchers find that married couples living in a war zone are more likely to experience domestic violence.

The team—led by Cari Clark, a former doctoral student at the Harvard School of Public Health now at the University of Minnesota Medical School—found that husbands exposed to political violence are nearly twice as likely to be physically violent and more than twice as likely to be sexually violent toward their wives.

The researchers analyzed domestic violence statistics from 4,000 couples surveyed in the Gaza Strip between Dec. 2005 and Jan. 2006.

According to the study, the widespread poverty, political instability in the region at the time led to feelings of humiliation and frustration among Palestinian men.

Clark and her researchers speculate that the effects of political violence—which include injury, post-traumatic syndrome, constraints on mobility, and economic strain—prompt men to violently reassert their position of power in the only situation that remains under their control: the domestic sphere.

While gender inequality and traditional gender roles often lead to domestic violence, “exposure to political violence exacerbates [those] factors,” Clark said. “Political violence adds an additional stressor on the household.”