The Nuremberg Code of 1947 provided the definition of informed consent from which future definitions and regulations were derived. The first principle of the code states that voluntary consent of the human subject is absolutely essential. The individual should be able to “exercise free power of choice, without the intervention of any element of force, fraud, deceit, duress, over-reaching, or other ulterior form of constraint or coercion.” The individual should be of sound mind and old enough to have the “legal capacity to give consent” and have “sufficient knowledge and comprehension of the elements of the subject matter” of the research so that he or she is able to make a knowledgeable and enlightened decision. This informed decision-making requires that the subject be told the nature of the research; the duration and purpose of the study; the methods or procedures to be performed; any risks, hazards, or inconveniences; and any health effects that might possibly be attributed to the research. In order for the consent to be recognized as valid, it must be voluntary and informed, the subject must be competent, and the subject must understand the information.
The ethical principle of respect for persons is the basis of the requirement for informed consent. The duty to respect the rights of others to be self-determining means that individuals have the right to be left alone and to make free choices. According to the Belmont Report (National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research, 1979), “respect for persons incorporates at least two ethical convictions: first, that individuals should be treated as autonomous agents, and second, that persons with diminished autonomy are entitled to protection. The principle of respect for persons thus divides into two separate moral requirements: the requirement to acknowledge autonomy and the requirement to protect those with diminished autonomy.” The Belmont Report defines the autonomous person as “an individual capable of deliberation about personal goals and of acting under the direction of such deliberation.”
The Belmont Report acknowledges that not every human being is capable of self-determination and that these persons are in need of extensive protection. The extent of this protection is dependent upon the risk of harm and the likelihood of benefit from the research procedures. In addition, respect for persons demands that subjects enter into research voluntarily and with adequate information. When considering the participation of vulnerable populations in research, the ethical principle of respect for persons is a matter of balancing competing claims urged by the principle itself, i.e., balancing the right of the individual to participate with the right of the vulnerable person to be protected from undue influence or coercion.
Investigators must include in their protocols a thorough description of the process by which potential subjects will be asked to participate in their research study. The protocol must describe a process that allows potential subjects sufficient time to consider participation; removes any impediments to the autonomy of the individuals as they ponder participation; and includes procedures that evaluate a potential subject’s understanding of study procedures, risks, and benefits. In some cases a third party is included in the consent process to serve as a witness or as a surrogate decision-maker. After agreeing to participate, subjects are typically asked to sign a consent form. Consent forms must contain specific information and be written in a style that is readily understandable to subjects. More information on the following topics can be found at the links listed in the box at right: