X substance misuse and/or withdrawal leading to psychiatric symptoms or illness (emergence of depression post‑detoxifcation, with insomnia and low mood), X a psychiatric problem that is worsened by substance misuse (a person with high anxiety of danger from others who uses cannabis to relax, but fnds that the cannabis can increase their paranoia, leading to increased alienation), X substance‑misuse and mental health problems that do not appear to be related to one another (someone who has an ongoing anxiety problem that is neither lessened nor worsened by drug or alcohol use). While in prison, where there is less ready access to illicit drugs, a patient’s mental state may appear stable. On the other hand, a relatively low‑stimulus environment such as prison can further mask existing mental health problems. Even low or moderate drug use (relatively small and infrequent consumption of drugs such as cannabis or amphetamine) that is not problematic for the great majority of substance users can have detrimental efects on persons with serious mental health problems. Diferent interventions are needed to manage withdrawal from alcohol and all drugs of dependence, and to manage opioid maintenance and prevent a relapse into problems of drinking or drug use after release.33 X Opiate‑dependent patients arriving in prison custody with serious mental health problems should be stabilised – rather than detoxifed – for a minimum period of two weeks. Quick detoxifcation should be avoided. X Benzodiazepine withdrawal may cause the emergence of symptoms of psychosis; patients with a previous history of thought disorder may be more vulnerable to this efect. A period of stabilisation may be required before any further reduction in diazepam is considered. Anxiety and self‑harm can emerge as a result of withdrawal of benzodiazepines; stabilisation followed by a slower reduction may again be indicated. X Withdrawal from stimulants can cause a brief but sometimes profound depression. It may take from one week to several months to resolve this, as the central nervous system adapts physiologically to the changed chemical environment. During this time a prisoner may be at enhanced risk of suicide or self‑harm. Additionally, stimulant use can cause a 33. A guide for the management of dual diagnosis for prisons. Department of Health, London (2009). Psychiatric care and treatment plans Page 47