One-hundred-ninety-nine adult mental health service users were interviewed with a protocol that included the Childhood Trauma Questionnaire, the Structured Clinical Interviews for Axis I and II DSM-IV disorders, the Global Assessment of Functioning scale, the SCORE family assessment measure, the Camberwell Assessment of Need Short Appraisal Schedule, and the Readiness for Psychotherapy Index. Compared to a U.S. normative sample, Irish clinical cases had higher levels of maltreatment. Cases with comorbid axis I and II disorders reported more child maltreatment than those with axis I disorders only. There was no association between types of CM and types of psychopathology. Current family adjustment and service needs (but not global functioning and motivation for psychotherapy) were correlated with a CM history. It was concluded that child maltreatment may contribute to the development of adult psychopathology, and higher levels of trauma are associated with co-morbid personality disorder, greater service needs and poorer family adjustment. A history of child maltreatment should routinely be determined when assessing adult mental health service users, especially those with personality disorders and where appropriate evidence-based psychotherapy which addresses childhood trauma should be offered.