Traumatic brain injury (TBI) is highly prevalent in prison populations, with an estimated prevalence of 51%-82% according to a 2018 review. TBI has been linked to higher rates of interpersonal violence, recidivism, suicide, higher drop-out rates in rehabilitation programmes, and lower age of first conviction. Attention deficit hyperactivity disorder (ADHD) has been shown to be associated with an increased risk of interpersonal violence, and previous TBI. Little is known about prevalence of TBI or ADHD amongst inpatients in secure psychiatric settings in the UK. We aimed to estimate the prevalence of TBI and ADHD in inpatients admitted to a psychiatric intensive care unit (PICU) and to low and medium secure units across three London mental health NHS trusts.

60 male participants were identified through prospective purposive sampling. Three questionnaires were administered: the Brain Injury screening Index (BISI); Adult ADHD Self-Report Scale v1.1 (ASRS); and the Brief-Barkley Adult ADHD Rating scale (B-BAARS). We also reviewed medical records of participants, age, psychiatric diagnoses, level of education, and convictions for violent and/or non-violent offences, number of admissions, and length of current admission. Ethical approval was granted by the local research ethics committee

67.8% of participants screened positive for a history of head injury, and 68.3% and 32.2% screened positive on the ASRS and B-BAARS respectively. 38.33% recorded greater than one head injury on the BISI. The most commonly recorded psychiatric diagnoses were schizophrenia (43.33%), schizoaffective disorder (23.33%), Bipolar Affective Disorder (11.67%), and Unspecified Non-Organic Psychosis (10.00%). Screening positive on ASRS was associated with screening positive for previous head injuries BISI (p = 0.01, ꭕ2). No other statistical associations were identified.

A relatively high proportion of participants screened positive for head injury and ADHD in this population. A history of head injury was associated with positive screening on the ASRS, which is consistent with previously reported associations between these conditions in other populations. A similar relationship was not seen with the B-BAARS however, and it is notable that fewer participants in the sample screened positive on the B-BAARS than using the ASRS. Few (n = 5) patients were able to provide detailed descriptions of head injuries using the BISI, suggesting that the BISI may not be suitable in this specific population as a screening tool.