2.  Health problems with which people enter custody in prison have a higher prevalence of mental health conditions than adult males (Borril et al, 2003; Chitsabesan & Hughes, 2016). Despite the high level of need, these mental health conditions are frequently underdiagnosed and poorly treated in custody. Recent international studies have evidenced the higher prevalence of prior traumatic brain injury (‘TBI’) among criminally involved populations compared with general populations (Williams et al, 2018). TBI symptoms range from mild and temporary to severe. The condition compromises neurological functions that are important for self-regulation and social behaviour and can increase the risks of behavioural and substance use disorders, psychiatric morbidity, self-harm and suicide. TBI has been identified as a potential cause or contributing factor in a range of cognitive and personality disorders and other conditions that have been shown to increase risk of crime, notably violent crime. People come in with a lot of trauma. Living in the middle of it is really extreme. It’s difficult. I saw so many people with the hatched scars on their arms, no hairs even grow on their forearms any more… The radiating trauma of people in jail is just hard to describe. Male ex-prisoner, England People with intellectual disabilities are also over-represented in prison populations, although studies differ as to prevalence (Fazel et al, 2008). These individuals experience significant limitations both in intellectual functioning (reasoning, learning, problem solving) and in adaptive behaviour, which covers a range of everyday social and practical skills.6 These characteristics can increase risk of conflict with the law. Drug and alcohol use disorders are highly prevalent among people entering custody. American research has found that half of the country’s prison population met criteria for drug abuse and dependence at the time of their arrest (National Center on Addiction and Substance Abuse at Columbia University, 2010) and that 24 – 36 per cent of the country’s heroin addicts pass through prisons each year (Boutwell et al, 2007). It has been estimated that 18 – 30 per cent of men and 10 – 24 per cent of women entering prisons in the United States of America, the United Kingdom and New Zealand meet criteria for alcohol misuse or dependence (Fazel et al, 2006). People entering custody also have high rates of comorbidity for substance misuse and mental illness (for example, Butler et al, 2011). Research in England has shown that the majority of people entering prison with mental health problems had also experienced one or more of the following (Durcan, 2008): • trauma and abuse • limited education • addiction or problematic substance misuse • poor general health • a history of unemployment • poverty and debt • homelessness Challenges like these can easily propel people with underlying mental health problems into (often frequent) contact with the criminal justice system. This may happen because the police are often the first agency called on to intervene when a person experiences severe distress or a mental health crisis, whether or not a crime has been reported. This can escalate rapidly into being charged with an offence and perhaps spending time in custody. In some countries the police may be under a duty to take action (which can include forcibly removing a person to a place of safety) if they assess someone as having a mental health problem and needing immediate care. This is the case in England and Wales, where police custody can be used as a place of safety if no other 6 From the website of American Association on Intellectual and Developmental Disabilities: https://aaidd.org/intellectual-disability 5