How does cognitive impairment affect decision-making capacity for treatment in older adults with dementia, and how should clinicians assess capacity?

• A. Capacity depends only on age, not cognitive status.
• B. Capacity is a global trait that is always reduced in dementia; assess only if asked by family.
• C. Capacity is task-specific; dementia may reduce capacity; assess understanding, appreciation, reasoning, and ability to communicate a choice; involve surrogate decision-makers when lacking.
• D. Capacity is irrelevant to treatment decisions.

Answer: (C)

Decision-making capacity for treatment in dementia is task-specific and can change with the complexity of the decision. A person with dementia may have the ability to understand some options and make a choice, while for other decisions their capacity may be diminished. The key is to assess four core abilities: whether the person can understand the information about the diagnosis, prognosis, and treatment options; whether they can appreciate how that information applies to their own situation and values; whether they can reason about the options and foresee potential outcomes; and whether they can communicate a clear, consistent choice.

Clinicians should use a structured approach to gauge these abilities in the specific treatment being considered. If the patient demonstrates understanding, appreciation, reasoning, and a stable preference, they can participate in the decision. If capacity is lacking for that decision, involve surrogate decision-makers who know the patient’s values and preferences, and document how the surrogate should apply substituted judgment or act in the patient’s best interests. Capacity is not determined by age or by a dementia diagnosis alone; it requires careful, case-by-case assessment tied to the particular treatment decision.