are challenging. For a relatively small number, in its most severe forms, it is linked to a serious risk of harm to themselves and to others. These ofenders have highly complex psychological needs that create challenges in terms of management, treatment and maintaining a safe working environment. Specialised units have demonstrated the ability to manage the most difcult ofenders safely and constructively, and deliver high‑quality therapeutic approaches; evidence is beginning to show a signifcant decrease in adjudi‑ cations and violent incidents. Guidelines have been developed for the treat‑ ment and management of personality disorders35 that are helpful in planning services for these categories of prisoner. The focus should be on the reduction of ofending behaviours, violence, aggression and substance abuse. Persons with psychopathy and those who meet the criteria for dangerous and severe personality disorder represent a small proportion of people with antisocial personality disorders. However, they present a very high risk of harm to others and consume a signifcant proportion of welfare services. Cognitive and behavioural interventions, for example, can focus on reducing ofending and other antisocial behaviour. Such interventions should be adapted to this group by combining concurrent individual and group sessions and should be longer in duration and supported by continued follow‑up and close monitoring. Pharmacological interventions should not be routinely used to treat person‑ ality disorders or associated behaviours of aggression, anger and impulsivity. However, pharmacological interventions for co‑morbid mental disorders, in particular depression and anxiety, could be necessary. When starting and reviewing medication for co‑morbid mental disorders, particular attention should be paid to issues of adherence and the risks of misuse and overdose. Treatment for any co‑morbid disorder is of the utmost importance and should happen regardless of whether the person is receiving treatment for a personality disorder, because efective treatment of co‑morbid disorders may reduce the risk associated with psychopathy or dangerous and severe personality disorder. American Journal on Addictions 8/4 (1999), 279‑92; Nace E., Davis C. and Gaspari J., “Axis II co‑morbidity in substance abusers”. American Journal of Psychiatry 148 (1991), 118‑20; Singleton N., Meltzer H. et al., Study of psychiatric morbidity among prisoners in England and Wales. Ofce for National Statistics, London (1998). 35. NICE Clinical Guidelines: Antisocial personality disorder: treatment, management and prevention. NHS (2009); NICE Clinical Guidelines: Borderline personality disorder: the NICE guideline on treat‑ ment and management. British Psychological Society/Royal College of Psychiatrists (2009). Psychiatric care and treatment plans Page 49