The research was led by Margaret Cutajar and included research by Professor Paul Mullen, Professor James Ogloff, Dr Stuart Thomas, Associate Professor David Wells and Josie Spataro.
The findings of the study were reported in the November issue of Archives of General Psychiatry, one of the JAMA/Archives journals.
Previous studies established that abused children were more likely to develop depression, anxiety, substance abuse, borderline personality disorders, post-traumatic stress disorder and suicidal behavior, according to background information in the article.
The authors found that "the possibility of a link between childhood sexual abuse and later psychotic disorders, however, remains unresolved despite the claims of some that a causal link has been established to schizophrenia."
The research data from police and medical examinations of sexual abuse cases was compared to a statewide register of psychiatric cases. Rates of psychiatric disorders among 2,759 individuals who had been sexually abused when younger than age 16 were compared with those among 4,938 individuals in a comparison group drawn from electoral records.
Over a 30-year period, individuals who had experienced childhood sexual abuse had double the rate of those in the comparison group of psychosis overall (2.8 percent vs. 1.4 percent) and schizophrenia disorders (1.9 percent vs. 0.7 percent).
The authors concluded that "the risks of subsequently developing a schizophrenic syndrome were greatest in victims subjected to penetrative abuse in the peripubertal and postpubertal years from 12 to 16 years and among those abused by more than one perpetrator."
The results establish childhood sexual abuse as a risk factor for psychotic illness, but do not necessarily translate into abuse causing or increasing the risk of developing such a disease. Many cases of childhood sexual abuse never come to light and the overall population of abused children maybe significantly different from those whose abuse is detected by officials.
"Children who come to attention following childhood sexual abuse should receive ongoing clinical and social support in the knowledge that they are at greater risk of developing a psychotic illness."
The authors recommend that "such treatment, in our opinion, should focus on improving the current functioning and adaptation to the demands of the transition from adolescent to adult roles rather than primarily on the abuse experience itself. Such an approach should benefit all victims, irrespective of whether they have the potential to develop a psychotic illness."
Source: Monash University