How do you determine if someone lacks mental capacity to make informed medical decisions?

Determining Mental Capacity for Medical Decision-Making

To determine if someone lacks mental capacity to make informed medical decisions, you must assess four key abilities: understanding, appreciation, reasoning, and communication of choice, using a structured approach that documents specific deficits in these areas. 1

Two-Step Assessment Process

Step 1: Establish Presence of Mental Impairment

• Determine if there is an impairment or disturbance affecting the person's mind or brain 2
• This can include:
  • Permanent conditions (e.g., Alzheimer's disease, intellectual disability)
  • Temporary conditions (e.g., intoxication, delirium, head injury)
  • Psychiatric illness (though mental illness alone does not automatically mean incapacity) 2

Step 2: Functional Assessment of Decision-Making Abilities

Assess the following four elements:

1. Understanding

   • Ask the patient to explain in their own words:
     • Their medical condition
     • The proposed treatment or intervention
     • Alternative options
     • Risks and benefits of each option 1
   • Document specific deficits in understanding

2. Retention

   • Determine if the patient can remember the information long enough to make a decision 2
   • Test by asking them to recall key information after a short interval

3. Weighing Information

   • Evaluate if the patient can:
     • Compare options using personal values
     • Provide logical reasons for their choice
     • Demonstrate consistent reasoning 1
   • Look for ability to describe consequences of different choices

4. Communication

   • Assess if the patient can clearly express their decision by any means (verbal, written, sign language, or established codes like blinking) 2
   • Document the method of communication used

Documentation Requirements

When documenting lack of capacity, include:

• The specific mental impairment or disturbance present
• Which specific abilities the patient lacks (understanding, retention, weighing, communication)
• Examples of responses demonstrating these deficits
• The context of the clinical situation
• Information provided to the patient
• Conclusion about capacity determination
• Next steps (surrogate process) 1

Important Principles to Follow

• Presumption of capacity: All adults are presumed to have capacity until proven otherwise 2
• Decision-specific assessment: Capacity is specific to each decision, not global 2
• Proportionate assessment: More complex or risky decisions require more thorough capacity assessment 1
• Avoid common pitfalls:
  • Do not rely solely on diagnosis, physical appearance, or cognitive screening tests 1
  • Do not label someone incapable merely because they make an unwise decision 2
  • Do not fail to reassess capacity, as it may fluctuate 1

Legal Considerations

• Legal frameworks vary by jurisdiction (e.g., Mental Capacity Act 2005 in England and Wales, Adults with Incapacity Act 2000 in Scotland) 2
• Documentation should reflect awareness of applicable legal standards 1
• In cases of uncertainty or dispute about capacity, seek legal advice, especially when dealing with highly irrational decisions 2

When Capacity is Lacking

If a patient lacks capacity:

• Identify the appropriate surrogate decision-maker according to jurisdiction's laws
• Ensure decisions align with previously stated treatment preferences or best interests
• Document the surrogate decision-making process 1

Remember that capacity assessment protects both patient autonomy and welfare by ensuring that those who can make their own decisions are allowed to do so, while those who cannot are appropriately supported.