What makes consent valid
All four must hold. Miss one and the consent is not consent:
- Voluntary — no coercion, from clinicians or family
- Informed — the nature of the treatment, material risks, alternatives, and what happens with no treatment
- Given by a capable patient
- Specific to the proposed treatment
"Material risk" is judged by the reasonable patient standard: what would this patient, in these circumstances, want to know? A rare risk of a catastrophic outcome must be disclosed; a common risk of a trivial one may not need to be.
Capacity is decision-specific
A patient is capable if they can:
- Understand the information relevant to the decision, and
- Appreciate the reasonably foreseeable consequences of deciding either way
Two consequences the exam leans on:
- Capacity is assessed for this decision, at this time. Someone can lack capacity to manage finances and retain capacity to refuse an amputation.
- An unwise decision is not incapacity. A capable patient may refuse life-saving treatment for reasons you find irrational. Diagnosis alone — dementia, schizophrenia, intoxication — never settles the question.
Minors
Canada largely follows the mature minor doctrine: there is no fixed age of consent for treatment. A minor who demonstrates capacity for the specific decision consents for themselves, and their confidentiality is protected.
Quebec is the exception the exam likes: 14 and over may consent to their own care, with a duty to inform parents if the minor is admitted for more than 12 hours.
When the patient is not capable
Turn to the substitute decision maker, following the provincial hierarchy (typically: court-appointed guardian → attorney for personal care → spouse/partner → child or parent → sibling → other relative).
The substitute decides in this order:
- Prior capable wishes of the patient, if applicable to the situation
- Best interests, weighing values and beliefs, likely improvement, and whether benefit outweighs harm
Note the direction: a valid prior wish binds the substitute. Their own view of best interests does not override it.
Emergencies
Treat without consent when there is a threat to life or health, the patient is incapable, and no substitute is available. The exception ends the moment either condition does. A known, applicable prior refusal — a clear advance directive, a competently expressed refusal — still stands.
Common questions
Can a capable patient refuse treatment that will save their life?
Yes. A capable patient may refuse any treatment, for any reason or none, including where refusal will result in death. Your obligation is to confirm capacity and that the refusal is informed and voluntary — not to change their mind.
Does a psychiatric diagnosis remove capacity?
No. Capacity turns on whether the patient can understand and appreciate this particular decision. Many patients with serious mental illness are fully capable of medical decisions, and capacity may fluctuate.