Best Interests Decisions Under the MCA: Practical Examples and the Checklist

In clinical negligence litigation, personal injury claims, and coronial inquests, disputes frequently arise concerning decisions made under the Mental Capacity Act 2005 (MCA). These disputes often hinge on whether a best interests decision was lawfully reached, particularly where the patient lacked capacity to consent to, or refuse, medical treatment. For solicitors and medico-legal experts, understanding the statutory framework, the role of expert evidence, and common pitfalls in such cases is essential to building a robust case.

The Legal and Clinical Framework

The MCA 2005 provides the statutory basis for assessing capacity and making best interests decisions in England and Wales. Under section 1(2), a person is presumed to have capacity unless it is established that they lack it. Section 2 defines a lack of capacity as an inability to make a decision due to an impairment of, or disturbance in the functioning of, the mind or brain. Section 3 sets out the functional test for capacity, requiring that the individual can understand, retain, use or weigh the relevant information, and communicate their decision.

Where a patient is found to lack capacity, section 4 of the MCA requires that any act done, or decision made, on their behalf must be in their best interests. The Act provides a non-exhaustive checklist of factors to consider, including:

• The patient’s past and present wishes and feelings, particularly any written statement made when they had capacity.
• The beliefs and values that would be likely to influence their decision if they had capacity.
• The views of anyone named by the patient as someone to be consulted, as well as anyone engaged in caring for the patient or interested in their welfare.
• Whether the patient is likely to regain capacity, and if so, whether the decision can wait until that time.

The Code of Practice to the MCA 2005 expands on these principles, emphasising the importance of a person-centred approach and the need to avoid assumptions based on age, appearance, condition, or behaviour. In medico-legal practice, expert witnesses are frequently instructed to opine on whether a best interests decision was lawfully made, whether the process complied with the statutory framework, and whether the outcome was reasonable in the circumstances.

Practical Examples in Medico-Legal Practice

To illustrate how best interests decisions arise in clinical negligence and personal injury claims, consider the following scenarios:

Example 1: Acute Medical Treatment in the Emergency Department

A patient presents to the emergency department with severe sepsis secondary to pneumonia. They are hypoxic, hypotensive, and confused. The clinical team determines that the patient lacks capacity to consent to intubation and ventilation due to acute delirium. A best interests decision is made to proceed with life-saving treatment, including mechanical ventilation and admission to the intensive care unit.

In subsequent litigation, the claimant alleges that the decision to intubate was not in the patient’s best interests, as they had previously expressed a wish not to be ventilated in a written advance statement. The instructing solicitor may seek an expert opinion from an acute medicine consultant or intensivist to address:

• Whether the patient’s lack of capacity was appropriately assessed at the time.
• Whether the advance statement was valid and applicable to the clinical circumstances.
• Whether the best interests process complied with section 4 of the MCA, including consultation with family members and consideration of the patient’s known wishes.
• Whether the decision to proceed with treatment was reasonable in light of the clinical evidence and the patient’s prognosis.

In such cases, the expert’s report may also consider whether the clinical team followed applicable NICE guidance on sepsis management, such as the Sepsis Six pathway, and whether any delay in treatment contributed to the patient’s outcome.

Example 2: Withholding or Withdrawing Life-Sustaining Treatment

A patient with advanced motor neurone disease is admitted to hospital with respiratory failure. They lack capacity to make decisions about their care due to cognitive impairment secondary to hypoxia. The clinical team, in consultation with the family, decides to withhold invasive ventilation and provide palliative care. The family later disputes the decision, alleging that the patient would have wanted aggressive treatment and that the best interests process was flawed.

The instructing solicitor may seek an expert opinion from a neurologist, palliative care consultant, or psychiatrist to address:

• Whether the patient’s lack of capacity was correctly assessed, including the impact of hypoxia on cognitive function.
• Whether the best interests process complied with the MCA, including consultation with family members and consideration of the patient’s known values and beliefs.
• Whether the decision to withhold treatment was reasonable in light of the patient’s prognosis and quality of life.
• Whether the clinical team followed current NICE guidance on the management of motor neurone disease and end-of-life care.

Example 3: Psychiatric Treatment and the Interface with the MCA

A patient with treatment-resistant schizophrenia is detained under the Mental Health Act 1983. They lack capacity to consent to antipsychotic medication due to psychotic symptoms. The responsible clinician makes a best interests decision to administer long-acting injectable antipsychotics. The patient later alleges that the decision was not in their best interests and that their objections were not adequately considered.

The instructing solicitor may seek an expert opinion from a psychiatrist to address:

• Whether the patient’s lack of capacity was correctly assessed, including the impact of their psychotic symptoms on their ability to weigh information.
• Whether the best interests process complied with the MCA, including consideration of the patient’s past and present wishes.
• Whether the decision to administer medication was reasonable in light of the patient’s clinical presentation and the risks and benefits of treatment.
• Whether the clinical team followed current NICE guidance on the management of schizophrenia and the use of long-acting injectable antipsychotics.

The Role of the Expert Witness in Best Interests Cases

Expert witnesses play a critical role in best interests cases by providing independent, objective opinions on the clinical and procedural aspects of the decision-making process. Under CPR Part 35, the expert’s duty is to the court, and their evidence must be impartial, evidence-based, and within their area of expertise. In best interests cases, the expert’s report may address:

• The patient’s capacity to make the relevant decision at the material time, including the impact of any acute or chronic medical condition on their cognitive function.
• The lawfulness of the best interests process, including whether the decision-maker considered all relevant factors under section 4 of the MCA.
• The reasonableness of the decision in light of the clinical evidence, the patient’s prognosis, and any applicable guidelines or standards of care.
• Whether any alleged breach of duty caused or contributed to the patient’s outcome, applying the legal tests of causation.

Common Pitfalls and Disputes in Best Interests Cases

Disputes in best interests cases often arise from the following issues:

1. Inadequate Assessment of Capacity

A common allegation is that the patient’s capacity was not properly assessed. The MCA requires a functional assessment of capacity, which must be decision-specific and time-specific. Experts may be instructed to critique the capacity assessment, particularly where:

• The assessment was conducted by a clinician without appropriate expertise.
• The assessment did not consider the impact of an acute medical condition, such as delirium or hypoxia, on the patient’s cognitive function.
• The assessment was not documented in sufficient detail to demonstrate compliance with the MCA.

2. Failure to Consider the Patient’s Wishes and Feelings

The MCA requires that the patient’s past and present wishes and feelings be taken into account. Disputes often arise where:

• The patient’s wishes were not adequately explored, particularly where they had made an advance statement or expressed strong views about their care.
• The decision-maker did not consult with family members or carers who had knowledge of the patient’s values and beliefs.
• The patient’s objections to treatment were not given sufficient weight.

3. Procedural Flaws in the Best Interests Process

The MCA does not prescribe a specific process for making best interests decisions, but the Code of Practice emphasises the importance of a structured, person-centred approach. Disputes may arise where:

• The decision was made by a single clinician without consultation with the multidisciplinary team or family members.
• The decision was not documented in the medical records.
• The decision was made in an emergency situation without adequate consideration of the patient’s best interests.

4. Disputes Over the Reasonableness of the Decision

Even where the best interests process is procedurally sound, disputes may arise over the reasonableness of the decision itself. For example:

• In cases involving life-sustaining treatment, the decision to withhold or withdraw treatment may be challenged.
• In cases involving psychiatric treatment, the decision to administer medication against the patient’s objections may be challenged.
• In cases involving surgical intervention, the decision to proceed with or withhold surgery may be challenged.

Practical Guidance for Solicitors

For solicitors handling best interests cases, the following steps can help ensure robust expert evidence:

1. Identify the Right Subspecialty

The choice of expert is critical. Consider:

• The patient’s underlying medical condition and the nature of the best interests decision.
• Whether the case involves multiple specialties, such as a patient with a complex medical history requiring input from both acute medicine and psychiatry.
• Whether the expert has experience in medico-legal work and is familiar with the legal tests and frameworks applicable to best interests cases.

2. Provide Comprehensive Instructions and Records

To enable the expert to provide a thorough opinion, provide:

• A clear and detailed letter of instruction.
• All relevant medical records, including the capacity assessment and best interests decision.
• Any witness statements or other evidence relevant to the patient’s wishes, feelings, beliefs, and values.
• Any applicable guidelines or standards of care, such as NICE guidance.

3. Consider the Need for Multi-Disciplinary Evidence

In cases where the best interests decision spans multiple specialties, consider whether multi-disciplinary evidence is required. For example:

• A patient with a traumatic brain injury may require input from a neurologist and a psychiatrist.
• A patient with advanced dementia may require input from a geriatrician and a palliative care consultant.

4. Address Causation Early

In clinical negligence claims, consider whether the expert evidence addresses whether any alleged breach of duty caused or contributed to the patient’s outcome. For example:

• If the allegation is that the patient’s capacity was not properly assessed, did this lead to a decision that was not in their best interests?
• If the allegation is that the best interests process was flawed, did this result in a delay in treatment or a suboptimal outcome?

Conclusion

Best interests decisions under the MCA are a frequent source of dispute in clinical negligence claims, personal injury matters, and coronial inquests. For solicitors and medico-legal experts, understanding the statutory framework, the role of expert evidence, and common pitfalls is essential to building a robust case. By instructing the right subspecialist and providing comprehensive instructions, solicitors can ensure that the expert evidence is tailored to the specific issues in the case.