This guide,which is now located in the Historic Articles section of this website, covers the law in England prior to the 2005 Mental Capacity Act which came into force in 2007. Different rules apply in other countries.

Jane Bernal (UK)

This guide, which is now located in the Historic Articles section of this website, covers the law in England prior to the 2005 Mental Capacity Act which came into force in 2007. Different rules apply in other countries.  A new article was published on this website in 2021.

There are lots of resources about the MCAct available from the National Mental Capacity Forum.

The Department of Health website contains important material on consent with which all health students should become familiar. You should also familiarise yourself with the guidance of your professional body. The BMA has a useful consent tool kit. (BMA 2006, Wong et al. 1999, 2000).

Capacity and competence are used interchangeably in this article to refer to a person's ability, in this instance to consent to a particular treatment or investigation, or an intervention. There are other legal situations in which a person's capacity may be questioned, for example, you might want to know if a person is able to make a will, to participate in research, to consent to have sex, get married or take out a mortgage. (eg (Iacono and Murray 2003) These questions raise different issues and are not covered in this article. Margeret Flynn's article describes the realities of healthcare decision making. If you have not read them already, the articles on communication  will also help you obtain truly informed consent.

Health professionals must respect the personal autonomy of the people who use their services. They must also try to do good (beneficence) and avoid harm (non-malificence). A proper understanding of consent is as central to the ethics of what we do as it is to its legality. (British Medical Association and Law Society 2004)

You are in a strange country where you do not speak the language. You are tired, thirsty, confused and in pain. Suddenly two strangers seize you and stick something sharp into your arm so that you bleed. Later they try to justify their actions, claiming, "We only wanted to help." Was this ethical?

You are involved in a road accident and are unconscious; you need surgery. Can the hospital refuse to treat you because you cannot sign the consent form?

You see the clinic nurse for an injection every three months but you do not know why. After several years, you discover it was a depot contraceptive. Was the nurse acting within English Law?

You fall and hurt your arm. It is very painful. It hurts when anyone touches it. You push the doctor away when she tries to examine it. She concludes that you are refusing treatment. The fracture fails to heal properly and you lose the use of your arm. Did the doctor do the right thing?

Adults expect to be asked whether they want medical treatment, and to have their decisions respected. They also expect that treatment will be given if they are not in a position to consent, for example, when they are unconscious. This is also true for adults with intellectual disabilities but is complicated by literacy problems, communication problems and unsubstantiated assumptions by professionals as well as by the fact that some people with intellectual disabilities will not be competent to make some decisions. (Arscott, Dagnan, and Kroese 1999)

  • Assume capacity. All adults have capacity unless and until they are shown not to
  • Capacity refers to the ability to make a particular decision at a particular time
  • Capacity can vary in the same person for different decisions and can fluctuate over time
  • A person with capacity has the right to refuse treatment
  • A health professional has a duty of care to patients
  • If an adult lacks capacity the health professional has a duty to provide treatment and care in the best interests of that adult, even if the person does not agree
  • In English Law nobody can consent on behalf of another adult
  • If you force treatment on a person who has capacity you may be assaulting them
  • If you deny treatment to a person who lacks capacity you may be neglecting them
  • The professional giving the treatment is responsible for assessing the patient's capacity, and for asking for any assistance they need to do so
  • Capacity depends on understanding
  • Understanding depends on effective communication and accessible information as well as cognitive abilities.
  • Even people who lack capacity may want and have the right to receive information
  • Consent obtained by force (under duress) is not valid
  • Consent can be shown behaviourally

Capacity refers to the ability to make a particular decision at a particular time.It is wrong to refer to a person as having or lacking capacity for all decisions.

For example, a woman who is able to choose whether to take ibuprofen when she has period pains may or may not have capacity to consent to laparoscopy. She may be competent to consent to laparoscopy but not to hysterectomy. Why might this be? In the first place, it is much easier to understand an immediate treatment to relieve a current symptom, pain, than it is to understand the need for investigation. Understanding distant long-term consequences, like sterility or disease prevention, is cognitively more difficult than dealing with an immediate problem. Understanding hysterectomy also involves some basic anatomy and physiology. The woman may be able to understand the idea of the doctor looking in her tummy without having much idea of where her womb is or what it does.

Health professionals also have to be more careful about capacity when the procedure is more serious and when the consequences of the decision, either way, could have dangerous or permanent effects. In particular, decisions about sterilization, termination of pregnancy and end of life decisions are recognized to be more complex. Such decisions may need to be made by a court.

Assume capacity. All adults have capacity unless and until they are shown not to.Alan was a 48-year-old man with severe cerebral palsy and some swallowing difficulties. His intelligence was difficult to test formally but he was thought to have mild intellectual disabilities. He enjoyed life in his group home and had many friends and a particularly close relationship with his key-worker. He could not speak but could communicate using head jerking, smiling and pointing with his eyes to objects in the world and on a Bliss communication board. He developed Absences, a form of epilepsy. His doctor offered to prescribe tablets. Alan wanted to know why. When she explained, Alan said that the Absences were not causing him any problems and that he hated having to take tablets. He understood that the tablets would prevent Absences but he did not think treatment was worth his while. The doctor respected his decision.

Two years later Alan's dysphagia was getting worse (NB this was not caused by non-treatment of the Absences). He had repeated chest infections and was losing weight. He had regular physiotherapy at home and all his food had to be liquidized. If he continued to take food by mouth, he was likely to die of undernutrition or, in the next episode, of aspiration pneumonia. The gastro enterologists at the local hospital offered Alan a feeding gastrostomy. He refused. The medical team asked for a careful assessment by a speech and language therapist. Did Alan really understand what a gastrostomy involved? Did he realize that he might die without one? He seemed to. The speech and language therapist introduced him to some other gastrostomy users: he indicated, "Good for them, not for me." He wanted to stay at home, to continue to eat and to die at home where his friends were. Alan's family and friends tried to persuade him but he did not change his view. A psychiatric assessment found no evidence of depression but that Alan seemed very aware of his increasing frailty and that he wanted to remain in control. Crucially Alan understood about death, in particular that it is permanent. Alan did not have a gastrostomy and died at home, as he wished.

End of life decisions are among the most difficult for health service professionals, both legally and at a personal level. The physiotherapists, speech and language therapists and doctors who had known Alan for many years found Alan's decision hard to live with, though they respected his right to make it. For some of them it conflicted with their own deeply held religious beliefs, beliefs that had drawn them to work with people with intellectual disabilities in the first place. Multidisciplinary assessment was needed to make sure that Alan really was competent to make a decision with such serious consequences.
If the decision is a complex one it may be useful to formally consider the ethical issues. This could be by consulting a clinical ethicist, group or committee if any of these is available.

A person with capacity has the right to refuse treatment. People have the right to make bad decisions. If a patient does not agree with what the health professional is recommending it does not mean that the patient is incompetent, just that the two hold different views. If a person does not consent, the reasons for this should be explored.

St George's medical students asked Graham, a man with intellectual disabilities, if they could take his blood pressure as part of a health check. He refused. He explained that he had been to hospital many times and hated needles. Even when the students explained that no needles were involved he continued to refuse to have the cuff put on his arm. He understood that they wanted to take his blood pressure for their education and to check that he was healthy. The investigation made him feel uncomfortable, so he refused it. The students quite rightly respected his competent decision. If a blood pressure measurement had been essential for Graham's health, the health professional involved would have had to build up Graham's trust and assure him no needles were involved. If it was likely that he might need injections or blood tests, Graham might benefit from treatment for his needle phobia. He would need to consent to this treatment.

A health professional has a duty of care to patients.
A person should not be denied treatment that is necessary to them merely because they are not competent to consent. Health services must not discriminate against people on grounds of disability.

You Can Make A Difference(Primary Care)
You Can Make A Difference (Hospital Services)

If an adult lacks capacity, the professional has a duty to provide treatment and care in the best interests of that adult, even if the person does not agree.

If you deny treatment to a person who lacks capacity, you may be neglecting them.

Angela, a young woman with severe intellectual disabilities became unwell. Even when she was well she did not use signed or spoken language though people who knew her well could tell how she was feeling and often could work out what she wanted. She was lying in bed with her legs drawn up, vomiting, and refusing to eat. On examination she had a temperature, her abdomen was obviously tender, especially in the right iliac fossa. She was admitted to hospital. The surgeon spoke to her and her mother. He explained that Angela needed surgery. Her mother and a day centre worker tried to explain to Angela that the doctors wanted to do an operation. From their experience of Angela they told the surgeon that they did not think she would be able to understand. They agreed with the surgeon that laparotomy seemed to be in her best interests. At operation she was found to have a severely inflamed appendix.

Magda, a 40-year-old woman with moderate intellectual disabilities is becoming increasingly easily tired and is having very heavy periods. She does not like meeting strangers but eventually care staff manage to get her to the GP's surgery. He notices that she looks very pale and that her feet look swollen. He tries to explain that she needs a blood test but, though she understands that it involves a needle and will hurt, it is clear that she cannot understand why he wants to do the test. Neither he nor the staff who know her well are able to make it clear to her. He concludes that Magda is not competent to consent. He therefore consults Magda's care staff and her mother. They all agree that it is in Magda's best interests for her to have a blood test. The GP asks the practice nurse to hold Magda's arm while he takes blood. Magda turns out to have severe anaemia, which is then treated. The GP also refers her to a gynaecologist. Magda's heavy periods are found to be due to cancer of the uterus which is also successfully treated. If Magda's GP had failed to arrange the necessary investigations he would have been failing in the duty of care he owed Magda.

A person's best interests go beyond what is medically recommended to cover the whole of someone's life. It is good practice to involve the people who know the adult best in decisions about best interests. The Department of Health guidance on people who are not competent to consent points out that, "'Best interests' go wider than best medical interests, to include factors such as the wishes and beliefs of the patient when competent, their current wishes, their general well- being and their spiritual and religious welfare. People close to the patient may be able to give you information on some of these factors. Where the patient has never been competent, relatives, carers and friends may be best placed to advise on the patient's needs and preferences. If an incompetent patient has clearly indicated in the past, while competent, that they would refuse treatment in certain circumstances (an 'advance refusal'), and those circumstances arise, you must abide by that refusal." (English Consent Law FAQs).

It can happen that a person refuses treatment but is not competent to make the decision. For example, Caroline, a woman with moderate intellectual disabilities, fell and broke her arm. It took a while for staff to get her to hospital and the Accident & Emergency Department was very busy. Caroline did not like strangers or busy places at the best of times. By the time the doctor saw her she had been in severe pain for some hours. She angrily refused to see the Doctor, shouting,"I don't want it, don't you dare touch me, you b…" He understood this as a refusal of treatment and discharged her. Interestingly, a few weeks after the acute pain had diminished she complained her arm did not work properly and agreed to go to the fracture clinic. However, the fracture healed abnormally and she developed a pseudarthrosis. In retrospect, it could be argued that Caroline was not competent to make the original decision because her underlying disability meant that she did not understand that the doctor had to examine her arm in order to make it better. She understood very well that touching her arm hurt and understandably refused to allow this. It could also be argued that she was in so much pain that she was unable to take on information and weigh it up to make a decision.

If you force treatment on a person who has capacity, you are assaulting them

It was Magda's GP who assessed her capacity to consent to a blood test.

The professional giving the treatment is responsible for assessing the patient's capacity, and for asking for any assistance they need to do so Yolande has recently developed diabetes. District nurses visit daily to give her insulin. For many years, she has had angry outbursts from time to time. When she is angry, she may break her own possessions, throw teacups or threaten to harm people. One morning she refuses to let the nurses in, shouting that she does not want to see them. She says she knows she needs the insulin or she will get ill but she does not care. The district nurses consult with a psychologist who has assessed Yolande's capacity in the past. He is able to tell them that Yolande has a good understanding of diabetes and its treatment. He asks whether there is any evidence that her blood sugar is raised or low at present as this could affect her capacity. (Capacity can fluctuate) Her blood sugar has been steady for several weeks. They decide Yolande has the capacity to refuse the insulin. They telephone her asking her to visit the surgery later if she decides she wants her injection after all. She turns up two hours later; the nurses give the injection, at her request. The district nurses who give the injection have the responsibility for assessing Yolande's capacity.

Capacity depends on understanding.

Understanding depends on effective communication and accessible information as well as cognitive abilities.

Even people who lack capacity may want information

It is the responsibility of the health professional who will be performing the intervention to make sure the patient understands in broad terms what the intervention is for, the main risks and benefits of the intervention and what may happen if the patient does not have the treatment. Where communication problems exist, whether or not the patient has intellectual disabilities, the health professional must present the information in a form that is accessible. Everybody is entitled to basic health information presented in a form they can understand. Accessible information comes in many forms because different people have different needs. Audiotapes are as much use to profoundly Deaf people as Braille leaflets are to most sighted people. Do not forget that many people with intellectual disabilities also have visual or hearing impairments.
Information should be given in the person's own language whether this is Urdu, English or British Sign language, so an interpreter may be needed. Many people with intellectual disabilities can read if the words and language are simple, the typeface is large and there is good contrast between the letters and the page. Line drawings can be used to illustrate the text.
Some people will be able to read Makaton or Widgit symbols (Steele et al 2001.)

Non-readers may need a story told entirely in pictures or photographs. Many people who can read a bit also prefer this approach as it puts them on a more equal footing with the health care professional. (Hollins, Bernal, and Gregory 1996)

Many people prefer to have support when they are asked to take on new information. It is important that supporters, whether they are friends, relatives or paid care staff, have good information and can adapt it to suit the person's level of understanding. Information will not necessarily make people feel less anxious. After all it is normal to have some anxieties about medical procedures.(Strydom and Hall 2001)

You need to give the person adequate accessible information. They will also need time to assimilate the information and to ask questions. If you have given them a book, leaflet or tape they may need to take it home and discuss your advice with other people. As the Department of Health guidance makes clear, "If the patient is not offered as much information as they reasonably need to make their decision, and in a form they can understand, their consent may not be valid." (English Consent Law FAQ).

Consent obtained by force (under duress) is not valid

It is clear that nobody can give valid consent with a gun held to his head. Duress can, however, be more subtle than this, for example a group of students heard a member of care staff tell a man with intellectual disabilities, "If you won't see the students, you won't be seeing your girl friend tonight". The students concluded that it would now be difficult for the man to make a valid decision to see them and that the staff member seemed to be abusing her power.

The differences in power between patients and health professionals as well as between cared for and care-giver are a common, perhaps inevitable, part of these relationships. When you add in the power differences between women and men, between different ethnic groups and between disabled and non-disabled people, it is easy to see how some people with intellectual disabilities may feel they were forced into a decision against their will. To avoid abusing their power in this way, health professionals need to give people permission to disagree with the "expert" without withholding expertise. You may need to remind people that they have the right to refuse treatment or ask for a second opinion.

Consent can be shown behaviourally
The district nurses call on Yolande who has diabetes. She lets them in, sits down and adjusts her clothing so that they can give the injection. Even though she has not said anything they can tell that on this occasion she consents to the treatment.

Step by step guide to assessing capacity to consent


A range of pictures is used in this article to illustrate the material that is available. These are from

Books Beyond Words

Also see the medical booklets and leaflets published by the Elfrida Society


Arscott, K., D. Dagnan, and B. S. Kroese. "Assessing the ability of people with a learning disability to give informed consent to treatment." Psychological Medicine.29(6):1367-75, (1999).

BMA. Consent toolkit. British Medical Association . 2006.

British Medical Association and Law Society. Assessment of Mental Capacity: Guidance for Doctors and Lawyers. 2 ed. London: BMJ Books, 2004.

Hollins, S., Bernal, J. and Gregory, M. Going to the Doctor. London: Books Beyond Words & Gaskell, 1996.

Iacono, Teresa and Vanessa Murray. "Issues of Informed Consent in Conducting Medical Research Involving People with Intellectual Disability." Journal of Applied Research in Intellectual Disabilities 16.1 (2003): 41-51.

Steele, P, et al. Going to the Dentist. 1 ed. Ballymena: Homefirst Community Trust, 2001.

Strydom, A. and I. Hall. "Randomized trial of psychotropic medication information leaflets for people with intellectual disability." Journal of Intellectual Disability Research.45(Pt 2):146-51, (2001).

Wong, J. G., et al. "The capacity of people with a 'mental disability' to make a health care decision." Psychological Medicine.30(2):295-306, (2000).

Wong, J. G., et al. "Capacity to make health care decisions: its importance in clinical practice." Psychological Medicine.29(2):437-46, (1999).

This article was written specially for the website in May 2006.