Consent to Clinical Research

Informed consent practices have evolved over time after instances were documented in which research participants were not treated fairly or respectfully, were not informed, or were subjected to unnecessary harm. Current federal regulations support the ethical treatment of persons in the research setting in that the participation is voluntary, that the risks outweigh the benefits, and that all people are given an equal chance to participate. When a researcher invites a participant into the research setting, the researcher is required to provide the necessary information, to ensure that the participant fully understands the information, and to stop the research if it is felt that these standards have not been met. Prior to enrollment in a research study, that candidate must provide valid consent for participation. That is, the participant must be fully informed about the research purposes, risks, benefits, freedom to withdraw consent, and other relevant information; must enter voluntarily into the research; and must be capable of making an informed decision. Informed consent to clinical research is important in the field of psychology and law, because psychological researchers must be aware of the requirements of conducting research and must protect themselves and also their research participants from any ethical breaches. Clinical research refers to studies con-ducted in a setting where clinical conditions, either medical or psychiatric, are diagnosed and treated. This research paper provides a historical basis for the evolution of informed consent, the requirements of informed consent, and will end with a brief discussion of the capacities of potentially vulnerable individuals who may have compromised ability to give a valid consent by virtue of impaired capacity or lack of voluntariness.

Historical Perspective

In research settings, individuals are protected by the doctrine of informed consent, which has evolved through policies, regulations, and professional codes. In the 1940s, unspeakable acts were committed when medical experiments on human subjects were conducted in concentration camps in Nazi Germany. In response to the atrocious experiments, the first formal document for conveying the ideas of protection of persons as human subjects and informed consent was developed. The Nuremberg Code set forth 10 guidelines for the ethical treatment of persons involved in research. The first statement of the Nuremberg Code states that the voluntary consent of the human subject is absolutely essential. Before an affirmative decision by the person can be made, one must know the nature, duration, and purpose of the experiment; the method and means in which it is conducted; and the reasonable inconveniences expected, which may possibly come from participation. The Nuremberg Code further states that experiments should only be conducted by scientifically qualified persons, that the results should yield fruitful results for the good of society, that all harm to the participant should be avoided, and that the participant may end the experiment at any time. The Nuremberg Code was expanded when the World Medical Association adopted the Declaration of Helsinki in 1964. The Code established independent ethical review committees to oversee all experimental procedures, which set the stage for the later development of institutional review boards (IRBs).

Although the Nuremburg Code helped to identify basic ethical principles of research, there were still instances in which egregious ethical breaches continued. The Tuskegee Syphilis Study, which began in 1932 and ultimately ended in 1972, was a research study in which medically ill patients were not offered effective medical treatment, which became available during the course of the research. In 1972, the unethical manner of the research project was made public and this ultimately led to the 1974 Research Act. The National Research Act was signed into law, thereby creating the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research. The charge of the commission was to identify the basic ethical principles that should underlie research involving human subjects and to develop guidelines that should be followed in accordance with the described principles. The 1979 Belmont Report emerged as a product of this work group and mandated that all researchers gain approval from an IRB before proceeding with any type of experimentation.

Principles of Beneficence, Justice, and Respect

The Belmont Report specified the three basic ethical principles governing scientific research. These include respect for persons, beneficence, and justice. Respect for persons specifies that individuals should be treated as autonomous persons, and those whose decision making is compromised should be given special protections and safeguards. Furthermore, participants must enter into a research setting voluntarily and with adequate information. Beneficence is applied in the research setting in that persons are entitled to participation that is free from harm and that maximizes possible benefits and minimizes possible harm. The principle of justice dictates that individuals should be treated fairly and equally in the research setting, according to their need, effort, contribution, and merit, and that all persons must share the responsibility of research.

The three principles of the Belmont Report are translated into informed consent by maintaining that persons are participating of their own free will and that the benefits to the person outweigh the risks. The Belmont Report served as the basis for the Code of Federal Regulations, which was approved in 1978. In addition, in 1993, the International Ethical Guidelines for Biomedical Research Involving Human Subjects were developed. In 2005, the Department of Health and Human Services released a revised edition of the Federal Code of Regulations on the Protection of Human Subjects. Title 45, part 46 of the U.S. Code of Federal Regulations upholds the application of the Belmont Report principles and is now generally accepted as the uniform policy for the protection of research participants. Outlined are specific definitions and statements as they apply to both federally and non-federally funded research projects.

Requirements of Informed Consent

The theory of informed consent to research is that a research participant is both voluntary and fully informed about the nature and consequences of an experimental situation before giving consent to participate. There are three essential elements to the doctrine of informed consent: voluntariness, information, and competency. The first element is that the person voluntarily consents to the procedure, in that the individual chooses freely to participate. To be voluntary, the person must consent without the presence of coercion, fraud, or duress, which may hinder the person’s decision-making ability. Stanley and Guido further elaborate that when an individual is consenting to participate in psychological research, one must consider the environment to ensure that the participant’s voluntary status is not compromised by the setting (e.g., prison, hospital, school).

Second, an individual must be fully informed of the proposed research setting to which he or she is consenting. The disclosure of information, which is provided in a formal informed consent document to the research participant, should include a description of the proposed procedures, its purpose, duration of the research procedure, the risks and benefits of participation, alternatives to participation, and the voluntariness of participation. Other issues that should be disclosed are that the individual has the opportunity to withdraw from the research setting at any time, issues of confidentiality, and any other pertinent information such as how to contact the main investigator.

The final element required to obtain informed consent is competency, which refers to the functional capacity to give valid consent to participate in research. Grisso and Appelbaum note that those persons who cannot use the disclosed information because of a lack of certain cognitive abilities are not capable of participating in an informed consent procedure. When the impairment reaches a certain level of severity, a determination can be made of incompetence. In legal terms, a de facto incompetence determination is made when inquiries into the person’s actual capacities reveal a sufficient lack in cognitive functionality.

When making a judgment about one’s decision-making capacities, three types of information are usually required as delineated by Grisso and Appelbaum: (1) the person’s clinical condition, (2) the person’s degree of functioning in tasks involving decision-making abilities, and (3) the situation-specific demands. There are four legal standards for assessing decision-making competence, which include the ability to communicate a choice, the ability to understand relevant information, the ability to appreciate the circumstances and likely outcome, and the ability to rationally manipulate the information. Grisso and Appelbaum also note that although four standards have been proposed, not all courts and jurisdictions apply all concepts in a determination of competency. Also of importance is that a person’s status on the four abilities is not all-or-none. A person usually possesses all the abilities but in varying degrees and one must consider the complexity of the decision being made in relation to the condition of the person making that decision.

For researchers it is important to provide all the necessary information to the potential participant so that he or she is able to make an informed decision. The information of the purposes, procedures, benefits, risks, and voluntary nature of participation must be outlined in a written document and signed by both parties. It is the responsibility of the researcher to ensure that the participant understands the information and is not being coerced in any way to participate.

Competency of Special Populations

When conducting research with normal healthy populations, researchers tend to presume that the participant is capable of understanding the material in the informed consent document and capable of making an autonomous decision of whether to participate or not. However, when conducting research with potentially vulnerable populations, the same assumption cannot necessarily be made. Potentially vulnerable populations include children and adolescents, who are vulnerable because of their developmental level and their susceptibility to coercion; prisoners and other institutionalized individuals by virtue of their lack of voluntary status; medical patients who may have impaired cognitive function ranging from being comatose to some memory impairment; and psychiatric patients as a result of possible compromised capacity to consent. Several empirical studies have examined the ability of psychiatric patients to provide informed consent; a brief summary of the findings follows. In persons with schizophrenia and psychotic disorders, mixed results have been produced. The consensus is that these types of patients, on the whole, perform more poorly than their non-ill counterparts on tests of competency. Several studies, however, have further noted that even with this divide, there is much heterogeneity among the schizophrenic patients and many are able to perform at a level similar to non-ill persons. Research on persons with affective disorders is somewhat more promising, with this group performing at a level similar to non-ill persons in most of the published studies. Finally, elderly patients with Alzheimer’s disease seem to be the population at the greatest risk for having impaired levels of cognitive processing and thus a diminished ability to provide informed consent.


  1. Appelbaum, P., Lidz, C., & Meisel, A. (1987). Informed consent. New York: Oxford University Press.
  2. Meisel, L., & Lidz, C. (1977). Toward a model of the legal doctrine of informed consent. American Journal of Psychiatry, 134(3), 285-289.
  3. Stanley, B., & Galietta, M. (2006). Informed consent in treatment and research. In I. Weiner & A. Hess (Eds.), The handbook of forensic psychology (3rd ed., pp. 211-239). Hoboken, NJ: Wiley.
  4. Stanley, B., & Guido, J. (1996). Informed consent: Psychological and empirical issues. In B. H. Stanley, J. E. Sieber, & G. B. Melton (Eds.), Research ethics: A psychological approach (pp. 105-128). Lincoln: University of Nebraska Press.
  5. Government Printing Office. (1949). Trials of war criminals before the Nuremberg Military Tribunals under Control Council Law (No. 10, Vol. 2, pp. 181-182). Washington, DC: Author.

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