The progressive ageing of a population leads to an increase in the number of people suffering
from cognitive deterioration. This requires particular attention in terms of the necessity
to assess these people’s cognitive functions and their capacity to make decisions.
The present systematic review analyses the clinical and ethical aspects of any assessment
of capacity, with a specific focus on the capacity of the individual to give informed
consent for medical treatment and also with regard to their testamentary capacity. The
results indicate that the concepts of capacity, competence and decision-making need to
be better clarified, ad-hoc devised tools are required and a multidisciplinary, clinical and
legal approach to assessments of capacity needs to be adopted. This is crucial to guarantee
that the two ethical principles of capacity assessment are adhered to: respect for an
individual’s autonomy and the protection of fragile individuals.