Table 1 Differences between provisions for adults lacking capacity under Mental Capacity Act 2005 (MCA) and Medicines for Human Use (Clinical Trials) Regulations 2004 (CTR)

Who acts as decision maker

Researcher must consult:

Personal consultee-a person who is engaged in caring for the person or is interested in their welfare, except as a professional or for remuneration–friend, relative, unpaid carer, attorney acting under LPA, court appointed deputy

Nominated consultee-a person who has no connection with the project-healthcare professional, nominated individual

Legal representative is a person who, by virtue of their relationship, is suitable to act as their legal representative and is available and willing to act.

Personal legal representative–friend, relative.

Professional legal representative–the doctor primarily responsible for their medical treatment or a person nominated by their health care provider. Must not be connected with the trial.

Basis for the decision

Consultee asked for advice whether the participant should take part or would not have wished to participate. Responsibility whether to include the participant lies with the researcher

Informed consent given by the legal representative represents their presumed will. Representative to decide whether the participant would have wanted to participate had they capacity to do so.

Provision of information

Does not specify any provisions that the person has to be informed about the research once they have been assessed as lacking capacity

Person lacking capacity must have received information about the trial, its risks and benefits, according to his or her capacity before they can be involved.

Dissent/objection

Weight is given to any refusal or dissent from the individual lacking capacity, even when the person has little or no ability to understand the situation. If the person indicates (in any way) that he wishes to be withdrawn from the project he must be withdrawn without delay.

The explicit wish of a subject who is capable of forming an opinion and assessing the information to refuse participation in, or to be withdrawn from, the clinical trial at any time must be considered by the investigator

Level of risk permitted

Research must be connected with an impairing condition in the functioning of the mind or brain affecting the person, or its treatment. There must be reasonable grounds for believing that the risk to the person is negligible and that anything done in relation to the person will not interfere with their freedom of action or privacy in a significant way or be unduly invasive or restrictive.

The clinical trial must relate directly to a life-threatening or debilitating condition clinical condition from which the person suffers. There must be grounds for expecting that administering the product will produce a benefit to the person outweighing the risks or produce no risk at all