4.  Developing a health-informed approach to penal reform The prolonged exposure to [overcrowded, unhealthy conditions] is closely associated with the establishment of complex trauma, or, put differently, toxic stress. Indeed, prolonged exposure to traumatic circumstances can lead to a complex post-traumatic stress disorder as a result of continually having to be alert, vigilant and on the defence. Continued stress of this nature leads to a shift in brain chemistry whereby cortisol is elevated to an unhealthy level. This renders detainees highly susceptible to illness and disease on a physical level as well as post-traumatic stress on a psychological level. Paragraph 25, affidavit of A Smit, expert witness, Sonke Gender Justice v. the Government of South Africa, 2016) manage some forms of mental illness. If a person has intellectual disabilities, practical and tailored support can be put in place to ensure that the associated risks are managed. For some people, prison may be the first time in their lives that a mental health need is identified or support is provided. Recent research suggests that time in prison can produce improvements to mental health (for example Dirkzwager, 2018). The ‘Prisons Project NL’ research team led by Dirkzwager found that individuals who had mental health or substance use problems before imprisonment reported improvements in their symptoms and level of mental health after the first few weeks in custody. Reasons posited included that prisoners had often come from situations of deprivation and disorder into a more stable environment with access to healthcare. The decent and humane prison conditions prevailing in most prisons in the Netherlands may also be a factor. Whether mental health improvement can occur in custody will of course depend on the prison conditions and environment and on the availability of care and treatment. Below, we describe some approaches that can help prisons to respond to mental health risks and needs and provide environments that safeguard mental health. Mental health screening in custody As soon as practicable, qualified staff should carry out detailed assessments on each new prisoner to assess his or her current mental health, inquire about the person’s prior mental health and any treatment history. This should include checking for any substance use issues, intellectual disabilities, age-related cognitive impairments, or other matters that could make the prisoner more vulnerable in custody. It is also important to monitor any conditions identified and ensure staff share information effectively and obtain clinical assistance where needed (World Health Organization, 2014). Custody also provides an opportunity to screen for and treat conditions associated with traumatic brain injury (TBI), which are common in criminally-involved populations but are often left undiagnosed (see section 2.2 above). The options include: • making greater use of screening programmes (such as those discussed in Williams et al, 2018) • providing treatment through neuro-rehabilitation techniques • using forensic interventions to manage the cognitive and behavioural disorders caused by or correlated with TBI • raising awareness among relevant professionals coming into contact with people who may have suffered TBI. Prison staff and mental health awareness Prison policies and the attitudes of prison staff are critical to protecting the mental wellbeing of prisoners, by preventing mental health issues from developing or worsening and by improving the situation of prisoners with mental illness. Conversely, negative and stigmatising attitudes by staff can mean that prisoners feel unable to ask for help when they need it. Prisoners in England (where levels of suicide and self-harm have risen to an 25