Assessing Patient Capacity

Assessing a Patient’s Capacity to make decisions

As a doctor you must presume that every adult patient has the mental capacity to give or withhold consent to any examination, investigation or treatment unless the contrary is proven.

In general practice assessing a patient’s capacity to make decisions is part of every encounter and the process is generally spontaneous and straightforward. During a consultation the doctor confirms the ability of their adult patients to understand their medical condition and options for care. For some patients however, the assessment may not be straightforward and you may have to assess a patient’s decision-making capacity more carefully than usual.

This are a number of clinical scenarios where this may occur in general practice including:

1. The patient has an abrupt change in mental status. This change may be due to infection, medication, an acute neurologic or psychiatric process or other medical problem;

2. The patient has a known history of impaired decision-making such as a chronic neurological or psychiatric condition or intellectual level concerns

The ability of a patient to make a decision may depend on the nature and severity of their condition, or the difficulty or complexity of the decision. Some patients may be able to make simple decisions but may have difficulty if the decision is complex or involves a number of treatment options. Other patients may be able to make decisions at certain times but not others because of fluctuations in their condition. Assessment of mental capacity, therefore, should always be a ‘decision-specific’ test ie whether a person lacks capacity to take a particular decision at a particular time. You must not assume that because a patient lacks capacity to make a decision on a particular occasion, they lack the capacity to make decisions at all, or will not be able to make similar decisions in the future.

These patients may require careful assessment but may still be able to make their own decisions.

There is, at present no statutory definition of capacity in Irish law but if the proposed Mental Capacity Bill 2008 is enacted a definition will be introduced. This draft defines capacity as ‘the ability to understand the nature and consequences of a decision in the context of available choices at the time the decision is made’.

The English Mental Capacity Act 2005 defines a person lacking in mental capacity as ‘if at a material time he is unable to make a decision for himself in relation to the matter because of an impairment of, or a disturbance in the functioning of the mind or brain. It does not matter whether the impairment or disturbance is permanent or temporary’.1

The test of capacity currently applied in Ireland is from the English case of Re: C where the court provided a three-part test that has to be fulfilled when assessing a patient’s capacity to consent (or refuse consent) to medical treatment. Can the patient:

  1. Understand and retain the information relevant to the decision in question;
  2. Believe that information, and;
  3. Weigh that information in the balance to arrive at a choice.

Assessments of mental capacity should only be carried out where there is a legitimate doubt about a patient’s capacity and not because the doctor disagrees with the patient or thinks their particular decision irrational.

In making decisions regarding a patient’s capacity you must make the care of the patient your first concern and always have his or her best interests foremost. Ensure that the patient is given every assistance to make decisions. Discuss treatment options in a place and at a time when the patient is able to understand and retain the information. Seek advice from family or friends of the patient around the best way of communicating with your patient if necessary, taking account of confidentiality issues and use communications aids if necessary. If a patient has difficulty retaining information, give him or her written record of your discussions, detailing what decision was made and why.

If your assessment leaves you in doubt about a patient’s capacity to make a decision you should seek advice from others involved in the patients care or those close to the patient who may be aware of the patient’s usual ability to make decisions.. You may also need to seek advice from colleagues with relevant specialist experience such as psychiatrists or neurologists. If you are still unsure about a patient’s capacity to make a decision you should seek legal advice with a view to asking a court to determine capacity.

1The Mental Capacity Act 2005 Part1 section 2


Share this article: