Associations between significant head injury and persisting disability and violent crime in women in prison in Scotland, UK: a cross-sectional study

Background: The prevalence of head injury is estimated to be as high as 55% in women in prison and might be a risk factor for violent offending, but evidence is equivocal. The extent of persisting disability is unknown, making decisions about service needs difficult. The UN recognises vulnerabilities in women in prison, but does not include head injury. This study aimed to investigate relationships among head injury, comorbidities, disability, and offending in women in prison. Methods: In this cross-sectional study, women were recruited between Feb 2, 2018, and Sept 30, 2019, from four prisons across Scotland, UK: Her Majesty's Prison (HMP) Cornton Vale, Her Majesty's Young Offenders Institute Polmont, HMP Edinburgh, and HMP Greenock (detaining approximately 355 individuals at the time of recruitment). Women were included if they were aged older than 16 years, fluent in English, able to participate in face-to-face assessment and provide informed consent, and did not have a severe acute disorder of cognition or communication. Head injury, cognition, disability, mental health, and history of abuse and problematic substance use were assessed by interview. History of head injury was assessed with the Ohio State University Traumatic Brain Injury Identification method and disability was assessed with the Glasgow Outcome at Discharge Scale. Comparisons were made between women with and without a history of significant head injury. Findings: We recruited 109 (31%) of the 355 women in these prisons. The sample was demographically representative of the approximately 400 individuals in women's prisons in Scotland. Significant head injury (SHI) was found in 85 (78%) of 109 women, of whom 34 (40%) had associated disability. Repeat head injury was reported in 71 (84%) of the 85 women with SHI and, in most cases, this resulted from domestic abuse that had occurred over many years. Women with a history of SHI were significantly more likely to have a history of violent offences than those without a history of SHI (66 [79%] of 85 women in the SHI group vs 13 [54%] of 24 women in the no-SHI group had committed a violent offence; odds ratio [OR] 3·1, 95% CI 1·2–8·1). This effect remained significant after adjusting for current factors (3·1, 1·1–9·0), including comorbidities associated with post-traumatic stress disorder, and was no longer statistically significant after adjusting for historical factors (3·3, 1·0–10·9), such as abuse as a child or adult. Women with SHI had spent longer in prison than women without SHI after adjustment for current (rate ratio 3·4, 1·3–8·4) or historical (3·5, 1·3–9·2) risk factors. Interpretation: It is recognised that women in prison are vulnerable because of histories of abuse and problematic substance use; however, history of SHI needs to be included when developing criminal justice policy, interventions to reduce mental health morbidity, and assessment and management of risk of violent offending. Funding: The Scottish Government.