GIRLS WHO WERE sexually abused as children are far more prone to risky sexual behavior and early pregnancy as adolescents, according to preliminary results of a decade-long tracking study conducted by researchers at USC and the National Institute of Mental Health (NIMH).

While previous studies of teen pregnancy and risky sexual behavior have documented high rates of prior sexual abuse, the USC-NIMH study is the first to document this connection by looking at the psychological and behavioral development of sexually abused girls as they were moving from adolescence to adulthood.

The NIMH-funded study – “Sexual Activities and Attitudes of Sexually Abused and Nonabused Adolescent Girls” – is the longest-running research project to track the psychobiological effects of sexual abuse on female development, said Penelope K. Trickett, an associate professor of social work and psychology. Trickett and NIMH researcher Frank Putnam are principal co-investigators in the study.

Trickett presented the findings in February at the Seventh Biennial Conference of the Society for Research on Adolescence in San Diego.

“Our preliminary analysis indicates that sexually abused girls are more likely to have babies and more likely to have them at a younger age,” Trickett said. “Furthermore, the abused girls in our sample were sexually active at a younger age and bore greater numbers of children than a comparison group of girls of similar age and socio-economic status who were not victims of childhood sexual abuse.”

The sample consisted of 160 girls living in the Washington, D.C., area. They were between 6 and 16 years old when the study began. About half of the subjects had been sexually abused by a family member and the other half had not. The sexual abuse started when the girls averaged 8 years of age and lasted for an average of two years.

The USC-NIMH research data were derived through a statistical analysis of results from a computer-given questionnaire on the girls’ sexual behavior and attitudes, together with the results of in-person interviews. The girls’ average age was 18 when the assessments came to an end this year.

STATISTICALLY SIGNIFICANT FINDINGS of the study include:

• Fifteen (24 percent) of the sexually abused group had borne at least one child, while eight (9 percent) of the comparison group had given birth.
• The average age of the sexually abused group was 18 when the girls gave birth to their first child, while the average age of the comparison group was nearly 20.
• Of the subjects who bore children, the sexually abused group had a greater number of children than the comparison group – a statistical mean of 1.9 children compared to 1.3 children for the comparison group.
• On average, the sexually abused girls reported having voluntary intercourse a year earlier (at 14.6 years of age) than the comparison-group girls (at 15.6 years of age).
• A significantly higher percentage of sexually abused girls said they were currently trying to get pregnant – 19 percent compared to 4 percent.
• In their answers to the questionnaire, the sexually abused group consistently scored higher on all factors dealing with sexual behavior and attitudes, including being preoccupied with sex, being promiscuous, having negative feelings about sex, and feeling pressure to have sex. However, preoccupation with sex was the only factor on which the groups’ scores were significantly different.

“This shows that while the sexually abused girls are having more sex and thinking about it more, they’re also having more negative thoughts about the experience and feeling more pressure,” Trickett said. “We’re trying to figure out what affects the wide variability in responses – why some do so poorly and others do so well as they become adults.”

In a separate analysis following an earlier assessment of the sample, the researchers looked primarily at behavioral and psychological problems associated with sexual abuse. “Girls who were abused by their biological fathers had the highest scores of acting out, disruptive behaviors and even bizarre thinking,” Trickett said.

The USC-NIMH researchers next will analyze how different kinds of abuse may relate to the degree of trauma and psychological stress experienced by each victim. They also will assess how this trauma and stress might be mediated by support from family, peers and psychotherapists, as well as by the physiological and psychological changes each girl experiences as she goes through puberty. In addition to the NIMH, the National Center of Child Abuse and Neglect and private foundations provided funding for the study. USC researcher Jennie Noll, based at the NIMH in Washington, D.C., is project director and (with Trickett and Putnam) a co-author of the study.