OBJECTIVES: To examine the associations between experiences of child maltreatment and mental disorders in the Australian population. DESIGN: Population-representative survey conducted by computer-assisted telephone interviewing. SETTING, PARTICIPANTS: Australian residents aged 16 years and older. MAIN OUTCOME MEASURES: Mental disorder diagnoses of lifetime major depressive disorder, current alcohol use disorder (mild, moderate and severe), current generalised anxiety disorder and current post-traumatic stress disorder. RESULTS: More than one in three Australians (3606/8503 surveyed participants; 38.0%; 95% CI, 36.7-39.3%) met the diagnostic criteria for a mental disorder. The prevalence of mental disorders in non-maltreated participants was 21.6% (95% CI, 19.9-23.3%; n = 851). This increased to 36.2% (95% CI, 33.5-38.9%; n = 764) for those who experienced a single type of maltreatment and 54.8% (95% CI, 52.6-56.9%; n = 1991) for participants who experienced multi-type maltreatment. Compared with non-maltreated Australians, maltreated participants had about three times the odds of any mental disorder (odds ratio [OR], 2.82; 95% CI, 2.47-3.22), generalised anxiety disorder (OR, 3.14; 95% CI, 2.48-3.97), major depressive disorder (OR, 3.19; 95% CI, 2.68-3.80) and severe alcohol use disorder (OR, 2.62; 95% CI, 1.83-3.76), and almost five times the odds of post-traumatic stress disorder (OR, 4.60; 95% CI, 3.00-7.07). Associations between experiences of child maltreatment and mental disorders were strongest for sexual abuse, emotional abuse and multi-type maltreatment. The strength of the associations did not differ by gender. Adjustment for childhood and current financial hardship and for current socio-economic status did not significantly attenuate the associations. CONCLUSIONS: Mental disorders are significantly more likely to occur in individuals who experience child maltreatment, particularly multi-type maltreatment. Prevention of child maltreatment provides an opportunity to substantially reduce the prevalence of mental illness and improve the health of the Australian population.
