Determining subjects’ mental capacity is essential for true informed consent
Evaluation should be ongoing
Whether a mentally ill or mentally impaired adult research subject is capable of giving informed consent has been a much-debated topic in recent years. Ultimately it’s up to IRBs to decide policies for handling research that potentially involves these populations.
"If consent is not informed, it can’t be voluntary, and there’s a big tension with that and the principle of beneficence and the principle of social justice," says Paul B. Gold, PhD, assistant professor of psychiatry in the department of psychiatry and behavioral sciences at the Medical University of South Carolina (MUSC). Gold also is the primary reviewer for the MUSC IRB.
"If we were to make the assumption that people with severe mental illness have no decisional capacity, which has been done in the last couple of decades by some people, this population doesn’t get to participate in research studies that ultimately could be of benefit to them," Gold explains. "Decisional capacity needs to be weighed against other principles."
On the other side of the equation, it has been a fairly common problem for IRBs and researchers to overlook the need to assess whether subjects actually have the capacity to consent to a particular research project, notes Paul Appelbaum, MD, professor and chair of the department of psychiatry at the University of Massachusetts Medical School in Worcester, MA.
The most common mistake IRBs and researchers make with regard to decisional capacity is to not recognize it as an issue, Appelbaum says. Also, IRBs and researchers who do realize this can be a problem often fail to create procedures and policies for assessing decisional capacity, he adds.
However, this doesn’t mean assuming that once a subject is determined to lack decisional capacity that the subject always will lack it. "This last issue is very important because we have a small but growing body of data suggesting that patients with impaired capacity may be able to ultimately understand what a study is about and reach a good decision as to whether or not to participate," Appelbaum says.
Appelbaum and colleague Thomas Grisso, PhD, with funding from the MacArthur Foundation, conducted a large-scale study of clinical competence in people with mental illnesses, and from that work they developed a tool, the MacArthur Competence Assessment Tools (MacCAT) for assessing decisional capacities. The latest version of MacCAT was published last year and can be used for clinical research (MacCAT-CR). A previous version was the MacCAT-CA for criminal adjudication.
All-or-nothing approach is the easiest
The problem is that the easiest approach to determining mental capacity of mentally unstable subjects is to make an all-or-nothing policy, and some people in the research industry have advocated for permitting no informed consents among these populations after decades of the opposite stand, Appelbaum says.
"In some cases, IRBs will swing 180° in the opposite direction and issue blanket rules regarding the necessity for wholesale screening of research subjects based on their diagnosis," Appelbaum says. "Often, for example, they’ll require that anyone with a mental disorder or, sometimes, a particular mental disorder undergo screening by an independent evaluator prior to being allowed to consent to participation."
The National Bioethics Advisory Commission (NBAC) has even recommended this policy, Appelbaum says. "But I think that’s a mistaken way to approach the issue — even though capacity is a very important issue for IRBs and principal investigators to pay attention to — because it misdirects resources," Appelbaum says. "Screening for capacity takes time and money and therefore should be done when high-risk populations at risk for incapacity are being involved in research and the research itself is of a sufficient degree of risk to warrant the investment of additional resources for the screening process."
Mental disorders encompass a wide spectrum of conditions and some are extremely unlikely to be associated with decisional capacity problems, Appelbaum says. "Even in a single diagnostic category, such as depression, [patients] with moderate or mild depression are extremely unlikely to have decisional incapacity, and those with extreme depression are more likely to have decisional incapacity," Appelbaum explains. "So to treat the two groups the same doesn’t make sense."
In a paper written by Rebecca Dresser, JD, a John Deaver Drinko-Baker & Hostetler Professor at Case Western Reserve University School of Law in Cleveland, there is a discussion of policy issues regarding people with mental disabilities. Titled Research Involving Persons With Mental Disabilities: A Review of Policy Issues and Proposals, the paper was published in March 1999 by the NBAC and is available at this web site: http://bioethics.georgetown.edu/nbac/pubs.html.
Dresser’s paper proposes that 13 basic questions be addressed in the deliberation of creating an appropriate federal policy on research involving adults with mental disabilities. These questions include these three key areas of consideration:
1. "What capacity standard(s) should apply to persons deciding about research participation? (Should a lower standard be applied to persons designating a research proxy decision maker?)"
2. "What procedures, if any, should be required to ensure that an individual’s decision to enter (and remain in) research is capable, informed, and voluntary? Should special procedures be required only in certain cases, such as research presenting no prospect of direct benefit? When, if ever, should an independent monitor be involved in such an evaluation?"
3. "Should limits be placed on the degree of risk permissibly presented in research involving incapable subjects? What prospect of direct benefits to subjects or benefits to society is sufficient to justify various degrees of research risks? Should a national review process be adopted to consider the justification for certain categories of research with risk-expected benefit ratios unfavorable to incapable or questionably capable subjects?"
Appelbaum notes that the NBAC’s focus on mental disorders and decisional capacity obscures the reality that many patients with other types of disorders, such as pain, disorientation, poor oxygen-carrying capacity, medications, etc., are likely to be unable to give competent consent. "What we need is a much more carefully refined and targeted approach to this issue, rather than simply saying in a blanket fashion that everyone who falls in this category should be treated similarly," he says. "Moreover, the risk that subjects run should be calculated into it."
Low-risk studies require little scrutiny
Studies involving very low risk of harm to subjects may not require as careful assessment of subjects’ decisional capacity as do studies with high risk, Appelbaum says. "In low-risk studies, the consequences of involvement are negligible, and the participants’ wishes at the moment should prevail," he says. "On the other hand, subjects entering into research with significant risk, we care very much whether they are making competent decisions."
While the debate continues over informed consent among mentally disabled populations, the MacCAT-CR tool offers IRBs and investigators a simple way to assess competence, Gold suggests. "We use it in our studies," he says. "We work on rehabilitation interventions for people with severe mental illness and severe substance use disorders because we have to be careful about whom we enroll if their decisional capacity is compromised."
Subjects who may not have decisional capacity problems include the obvious populations, such as those who are severely mentally ill or have dementia, but they also can include people who abuse controlled substances, patients who are seriously injured and under the influence of pain killers, and people who have life-threatening illnesses that are so anxiety-provoking that their reasoning ability is diminished, Gold notes. "Any one of us can be rendered in a heartbeat unable to give voluntary consent," Gold says.
However, investigators who follow normal practices of screening potential subjects for inclusion/exclusion criteria typically can adequately assess decisional capacity without relying on an independent monitor or the MacCAT-CR tool, Gold says. "Unless you’re dealing with people who are in acute stages of mental illness or acute mania or acute and severe depression, not everybody needs to be screened with MacCAT tools," Gold adds. "In talking with someone in an ordinary interview, you can get a sense of where they are and if it’s necessary to do a formal assessment."
Appelbaum suggests that investigators try different approaches to educating potential subjects about informed consent when it appears that there may be a problem with their comprehension. "They may need an opportunity to talk with people who’ve been in the study or watch a video or computer program about it, or learn about it in different ways," Appelbaum says. "You may think of these people as having something more of a learning disability than incapacity, and we’ll have to work harder to teach them about a particular project."
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content