Few clinical decisions are more difficult than whether or not to withhold treatment from patients who are unable to make this choice for themselves. This is because they bring into conflict a number of principles central to clinical practice, such as the duty to save life, the duty to relieve suffering, and the duty to heed patients' wishes. In North America, advance directives (‘living wills’) from patients, made when they are fully competent, have achieved considerable popularity in recent years as a possible way out of these dilemmas (La Puma et al, 1991; Molloy et al, 1991); unfortunately, it is by no means clear whether these can in fact provide a workable solution to the problem of treating incompetent patients (Hope, 1992). For the time being, decisions about withholding treatment will continue to be made by the health professionals immediately involved at the time, often junior staff with little experience or training, and there is a need for a professional consensus as to the factors that should be properly taken into consideration. This study investigates the current attitudes and approaches of psychiatrists and psychiatric nurses in one health district to this problem. It examines the criteria used, and the conditions under which decisions about administering or withholding treatments are being made.