Liaison psychiatrists are frequently asked to advise when patients refuse consent to medical intervention. This chapter aims to give practising clinicians a framework for understanding legal issues surrounding refusal of treatment in the general hospital context. Non-psychiatrists in general hospitals are unaware of the limitations of the mental health act (MHA) with respect to issues of non-consent, and may erroneously expect that it normally has a role where there is refusal of treatment for physical health in persons with mental disorder. Every adult who has reached the age of majority (18 years) has, a priori, the right and capacity to decide whether or not he/she will accept medical treatment, even if a refusal may risk permanent damage to his/her physical or mental health, or even lead to premature death. The chapter provides a series of case vignettes and commentaries with regard to law applied to clinical situations.

Every referral to liaison psychiatry presents its own clinical dilemmas. Some cases are straightforward and can be assessed and managed easily. Others are complex and require a whole host of liaison skills and a large investment of time. This chapter is composed of a number of 'problem cases'. They are intended to replicate the process of referral, assessment and management by liaison psychiatry. The cases have provided a different perspective and way of thinking about liaison psychiatry which is more familiar to the clinician. It is important to remember that liaison psychiatrists cannot possibly be familiar with the latest developments across the whole of the field of medicine, but they may well be expected to provide advice about patients with a wide range of physical and psychological problems. Mentoring is also useful for newly appointed consultant liaison psychiatrists, where a more experienced liaison psychiatrist can provide support and guidance.

Liaison psychiatrists may have misgivings when surgeons and physicians refer patients with alcohol problems. Epidemiological overviews including meta-analyses have quantified the relationship of alcohol consumption to morbidity and mortality. Psychiatrists should be aware that alcohol dependence can obscure psychiatric diagnosis. In clinical practice, where a behaviour change is implicated, the diagnostic process is a first step in therapy. Liaison psychiatrists see many patients whose present physical symptoms have been attributed to depression or anxiety. Wernicke's syndrome is believed to be due to critical deprivation of thiamine in neurons in the mid-brain or thalamus. It often has a rapid onset following weeks of heavy drinking which have interfered with the absorption of thiamine from the intestine. It is possible that acamprosate or calcium homotaurinate acts to stabilize glutamate receptors left oversensitive in the newly abstinent alcohol-dependent patient.