How does TCPS 2 address capacity and understanding in consent for participants with diminished autonomy?

• A. Provide additional protections, assess capacity, and involve substitute decision-makers or guardians as appropriate.
• B. Always require full capacity regardless of circumstances.
• C. Exclude participants with diminished autonomy.
• D. Permit consent from a family member only.

Answer: (A)

When participants may not have full capacity to understand and decide about research, the essential approach is to adjust the consent process to protect them while still respecting their autonomy as much as possible. The best answer captures three key steps that TCPS 2 requires: provide additional protections, assess capacity, and involve substitute decision-makers or guardians as appropriate.

Assessing capacity means checking whether the person can understand the information, appreciate the consequences of participation, reason about options, and communicate a choice. If capacity is lacking, researchers should implement additional safeguards tailored to the person’s situation—this can include simplifying information, using supported decision-making, involving a legally authorized representative, and ensuring ongoing monitoring and the option to withdraw. Involving substitute decision-makers or guardians is appropriate when a person cannot consent on their own, but their known values, preferences, or prior wishes should guide the decision as much as possible, with assent sought from the person whenever feasible.

The other options miss the reality TCPS 2 acknowledges: some people cannot provide full capacity, so exclusion is not appropriate; insisting on full capacity in every case is impractical and contrary to protective practices; and allowing consent from a family member only is too narrow, as the appropriate decision-maker may be a legally authorized representative, not just a family member.