A recent study found that repeated sexual assault victims report more psychological problems than previously thought.

About one in five women and one in 100 men have reported being raped. The prevalence increases to two in five among women and one in five among men who report experiencing other forms of sexual violence, such as repeated, unwanted sexual contact and sexual coercion, according to recent studies.

Researchers from the University of Missouri-Columbia found that those who are repeatedly assaulted but not necessarily raped show greater levels of psycho-behavioral consequences than earlier thought. They suggest that understanding patterns of sexual victimization and related consequences will help develop strategies to combat sexual assault frequency among adolescents.

"Our findings are important because we are able to identify some of the weaknesses and potential fallacies in classifying survivors based on the violence encountered during the assault," Bryana French, researcher and assistant professor of counseling psychology in the Department of Educational, School and Counseling Psychology, said in a statement. "Indirect, repeated or subtle manipulation tactics can lead to a lifetime of psychological consequences."

She added that researchers who study sexual assault typically assess victimization based on severity and rarely examine individual patterns of victimization.

For the study, French and her colleagues investigated the sexual victimization of those studied using a scale of sexual coercion including verbal coercion, substance-facilitated assault and forcible rape -- making this one of the few studies that examined all three types of sexual victimization.

Based on their findings, victims who are repeatedly assaulted through physical force as well as verbal coercion, or who are given unwanted substances like drugs or alcohol to pressure them into intercourse, showed the greatest levels of psycho-behavioral consequences including lower self-esteem, higher psychological distress and greater sexual risk-taking later in life.

"Most sexual victimization research tends to focus on forcible, violent rape while the subtler forms of sexual assault, like manipulation and coercion, are less studied," French said. "Unfortunately, we know that people who are victimized often experience re-victimization by the same or different individual. Our research focuses on those individuals who receive multiple forms of unwanted sexual advances and the psychological toll those experiences take on the victims."

The findings were recently published in the Journal of Interpersonal Violence.