Researchers have an ethical obligation to be sure that human participants are capable of making informed decisions when they are considering whether or not to be part of any study.
By Barton W. Palmer, PhD
September 2015, Vol 46, No. 8
Print version: page 62
Cite This ArticlePalmer, B. W. (2015, September 1). Study participants and informed consent. Monitor on Psychology, 46(8). https://www.apa.org/monitor/2015/09/ethics
Voluntary informed consent is essential to conducting ethical research with human participants. Valid consent rests on three pillars: the absence of coercion or undue influence, providing participants with information relevant to the decision at hand, and ensuring that participants have the capacity to use that information to make an authentic decision on whether to participate. Given that serious mental illnesses, neurodegenerative conditions and brain injuries can have deleterious effects on cognitive, affective and other mental processes, decision-making capacity can be an issue of concern when psychologists obtain consent for research from people with such conditions.
Generally, a person's capacity for making a decision involves four components:
All of the above are stated in reference to a decision about a particular research study. Although mental status, fatigue, anxiety, acute pain and other fluctuating factors can affect a person's ability to comprehend information at a particular moment, decisional capacity is not an intrapersonal trait, analogous to shyness or intelligence, but rather is a context-dependent construct. The relevant question, then, is not a participant's general capacity to make decisions, but rather his or her ability to understand, appreciate, reason and express a choice about participating in a specific research study. An individual may retain capacity for consent to a relatively simple research protocol, but have more difficulty with a decision about participating in a protocol in which the procedures and/or the risk-benefit considerations are more complex.
Researchers can improve study participants' comprehension of the study at hand by making the consent process more interactive — and doing so is particularly important when there may be concerns about a potential participant's decisional capacity. Many misunderstandings can be avoided or rectified through a simple iterative process of discussion whereby researchers explain the key information in lay terms, include visual aids where appropriate, and then ask the potential study participant to explain the essential information in his or her own words while providing corrective feedback, and reassessing comprehension as needed.
If an individual shows difficulty explaining essential information even after the researcher has provided corrective feedback, then it may be necessary to exclude the participant, or to conduct a formal assessment of his or her decisional capacity. Given the context-dependent nature of decisional capacity, such assessments should not be limited to standard cognitive screening measures, but should include one of the scales developed to specifically assess capacity to consent to research participation, such as the MacArthur Competence Assessment Tool for Clinical Research or the UCSD Brief Assessment of Capacity to Consent. The advantage of these measures is that they can be tailored to any specific research protocol for which a potential research participant is being considered.
One factor that should not generally be used to decide decisional capacity is the presence or absence of a particular diagnosis. Research indicates that many people with serious mental illnesses, at least outside the context of the most acute phases of illness, retain the capacity to understand, appreciate, reason and to make and express a choice about participating in research protocols (Appelbaum, 2006; Jeste, Depp, & Palmer, 2006). Notably in the case of schizophrenia, the bulk of empirical research suggests that, at least among outpatients, it is the cognitive deficits that frequently accompany this disorder that most directly affect decisional capacity, not the primary psychopathologic symptoms (Palmer & Savla, 2007). In short, although clinical conditions are often risk factors for impaired capacity, they are not synonymous with impaired capacity.
As put forth in the 1979 Belmont Report, the basic research ethics principle, Respect for Persons, incorporates two ethical convictions: Individuals should be treated as autonomous agents, and people with diminished autonomy are entitled to additional protections. Many of the ethical dilemmas that arise regarding informed consent for research can be seen as, at least partially, a tension in balancing these two components. Fully honoring the spirit of both of these components and ensuring valid informed consent thus requires that decisional capacity be considered on an individual basis and within the context of the specific decision at hand.
Barton W. Palmer, PhD, is a professor of psychiatry at the University of California, San Diego, and a member of APA's Committee on Human Research.