such treatment; medical examinations before, during and after treatment; access to outside consultation, including an independent second opinion; and regular evaluation of the treatment by an independent medical authority. The administration of anti‑androgens should be combined with psychotherapy and other forms of counselling in order to further reduce the risk of re‑ofending. Further, anti‑androgen treatment should not be a general condition for the release of sex ofenders, but should be administered to selected individuals based on an individual assessment. Surgical castration is an intervention that has irreversible physical efects, and direct or indirect mental health consequences. Further, there is no guar‑ antee that the result sought (lowering of the testosterone level) will last. The legitimate goal of lowering re‑ofending rates must be counterbalanced by ethical considerations linked to the fundamental rights of an individual.31 Surgical castration is no longer a generally accepted medical intervention in the treatment of sex ofenders. Irreversible medical interventions should never be carried out on prisoners or other detained persons unless there is a clear medical necessity. 2.7 Dual diagnosis in prisons At an estimate, 3‑11% of prison inmates have mental health problems (such as psychotic disorder or mood disorder) co‑occurring with a substance‑ abuse disorder.32 The term “dual diagnosis” covers a wide range of problems that have mental health and substance misuse in common. Dual diagnosis can have diferent meanings to diferent health‑care services, but the four commonest combi‑ nations are: Xa primary mental health problem that provokes the use of substances (such as someone sufering from schizophrenia who fnds that heroin reduces some of the symptoms), 31. Alexander M., Gunn J., Cook D. A. G., Taylor P. J. and Finch J., “Should a sexual ofender be allowed surgical castration?” British Medical Journal 307 (1993), 790‑93. 32. Edens J. F., Peters R. H. and Hills H. A., “Treating prison inmates with co‑occurring disorders: an integrative review of existing programs”. Behavioral Sciences & the Law 15/4 (1997), 439‑57. Prison health care and medical ethics Page 46