Background: There is limited data available regarding the most common forms of psychiatric illness, the occurrence of childhood adversity, and the link between childhood adversity and criminal and psychiatric outcomes amongst forensic inpatients. Aims: Using census data for all Scottish forensic inpatients, we investigated the most common primary psychiatric diagnoses in forensic settings, the occurrence of childhood adversity amongst forensic inpatients, and whether childhood adversity experiences significantly predict a range of criminal and psychiatric outcomes. Method: Data for the current study were drawn from 'The Scottish Forensic Network Inpatient Census' (N = 422). The Responsible Medical Officers and other members of the clinical team collected all data from official patient records. All forensic inpatients across high, medium, and low security sites were surveyed. Results: The majority of patients had a psychotic disorder as their primary diagnosis (86.4%), with schizophrenia being the most common (70.0%). Childhood adversity was highly prevalent (79.2%), with physical abuse being the most common adverse experience (40.1%). Increased levels of childhood adversity were significantly associated with an increased risk of criminal convictions, self-reported abuse of animals, suicidal and self-injurious behaviour, and problematic use of drugs or alcohol. Conclusions: Considering the association between adversity and psychosis, trauma informed care is essential for the mental health and forensic needs of this population.