If you’re an ordinary medical or surgical patient – or any patient other than a psychiatric patient – you can refuse any treatment that is being offered to you if you don’t want it – even if the outcome might be grave. However, there is one situation where despite your refusing, you can be forced to have the treatment. If you are incapable of making a treatment decision due to an impairment or disturbance in the functioning of your mind, and the proposed treatment is in your ‘best interests’, then you can be treated involuntarily, against your will. ‘Best interests’ gives regard what you would choose according to your deep values and commitments and personal life goals. A disturbance in the functioning of your mind might be due, for example, to a stroke, a head injury, a serious infection or the confusion commonly experienced after an operation. Restraining people like this is common in medical practice.

Now, if you’re a psychiatric patient, you can be treated against your will for entirely different reasons – reasons that have nothing to do with your ability to make a treatment decision for yourself or what is in your ‘best interests’. You can be detained and treated involuntarily if you are: first, diagnosed with a ‘mental disorder’ – usually vaguely defined; and second, you are judged to present a risk to your health or safety, or to the safety of other people. What constitutes a ‘mental disorder’ can be difficult to define, while the assessment of risk is subject to troubling inaccuracies, especially so for rare events like a suicide or serious violence.

The rules, then, governing involuntary treatment are entirely different in psychiatry to all the other specialities. They haven’t changed for the last 200 years or so, while those in the rest of medicine have evolved in the last 50 years as we have come to value patient autonomy more and ‘doctor knows best’ paternalism less.

Comparing the different rules in psychiatry versus the rest of medicine points up a stark discrimination against people with a mental illness. First, the psychiatric patient’s autonomy, self-determination or right to refuse treatment is not respected in the same way as that of the ordinary patient. Second, the reference to risk to other people in the risk criterion, means that people with a mental illness can be detained and treated on the basis of a supposed risk alone; the rest of us have to have committed an offence before we can be deprived of our liberty (or be strongly suspected of having done so). People with a mental illness are unique in being liable to this from of ‘preventive detention’.

How is it that we have accepted such discrimination for so long? The reason is that stigmatising stereotypes of people with mental illness are deeply embedded in our culture – that having ‘diseased minds’ they are incapable of ordinary thinking or judgement and thus their treatment choices are not to be taken seriously; and, that dangerousness is part and parcel of mental illness. Mental health law reinforces these prejudices. Research emphatically fails to support them

Well then, is there a legal framework that does not discriminate against people with a mental illness? Yes, there is. It is a ‘Fusion Law’. A key point is that it is ‘generic’; that is, it is the same law for everyone who may develop a problem with decision-making, whatever the diagnosis – ‘physical’ or ‘mental’ – and in any setting – medical, surgical, psychiatric or in the community. There is no need for a specific ‘mental health’ law. The framework is based on ‘decision-making ability and a form of ‘best interests’ which gives paramount regard to the person’s deep beliefs and values (or ‘will and preferences’, but tweaked with a few additions to make it applicable across all of medicine, from psychiatry to orthopaedics.

Being a generic law and thus applicable to all patients, the criteria for involuntary treatment must be workable in all settings. Practice will need to change in some respects – but for the better. The patient’s voice will be better heard. The need for coercive interventions – at present increasing alarmingly year on year – will likely be significantly reduced.

Finally, the Fusion Law is as close as one can realistically get to meeting the challenges of the UN Convention on the Rights of Persons with Disabilities (2006), which has been ratified by the UK. Some authorities claim this Convention effectively rules out ‘substitute decision making’, that is, decisions made in the place of someone who is deemed not able to make a decision. Such a position is, at least at present, not credible. The ‘fusion law’ aims to eliminate discrimination, as does the Convention, but leaves a morally defensible place – as a last resort, when all attempts at support have failed – for involuntary treatment.