Assent: Not just for kids anymore!
Most clinical research professionals are familiar with the concept of assent (in parallel with parental permission) as part of the process of informed consent when conducting clinical research in children. When the Institutional Review Board find it appropriate for assent to occur, the assent process for each study can vary from a brief verbal explanation of the research and verbal agreement up to full written document nearly or fully identical to an informed consent document and a written signature for older teenagers, and should be based on the age of the children, their developmental status, and their familiarity with medical procedures.[i] The reason we require assent from children is that even though they are not legally capable of providing consent to their medical care or research participation, we respect that they still have autonomy over their bodies and their persons, and we show this respect by asking for their agreement to include them in research studies.
The concept of assent has, for a long time, been thought of as applying only to pediatric research, and not really to other types of research where the participation may have diminished capacity and may not be able to provide informed consent for themselves. One situation which this is particularly applicable is research in progressive neurological conditions. A growing number of research ethicists, and Institutional Review Boards, are now suggesting- or even requiring- that researchers also obtain assent from adult research participants when the actual research consent is being provided by a legally authorized representative.
Since the concept of respect for persons is one of the fundamental tenets of the Belmont Report[ii], a foundational document of ethical principles for research, requiring assent for adult research participants seems completely appropriate, for the same reasons that it is for children. While potential participants may not have the legal capacity to make decisions for themselves, they may still be able to understand what’s happening to a significant degree, and to express their own wishes about research participation. Even if not able to understand the complexities of the research plan (e.g., the randomization of a clinical trial), they may be able to understand that extra blood draws are going to be taken to help researchers understand more about how to treat people with their condition.
As in children, the requirements and details of the level of assent information and the process in which assent is indicated (written, verbally, etc) may depend on both the condition being studied and the level of disability of the participant. If the IRB does make it a requirement to obtain assent, the instructions should include enough flexibility that the investigator can adjust the process as appropriate to the specific situation. This may also be true with ongoing consent/assent, in studies in which the participant has decisional capacity at the time they are initially enrolled but loses that capacity due to their condition, over the course of the study.
The ethical principle of respect for persons requires that we also consider when person with diminished decisional capacity, often referred to as “vulnerable participants”, may require additional protections in the research process. Obtaining assent in adults who are decisionally-impaired allows is to provide this additional protection while also addressing the ethical principle of justice by allowing these participants to be part of research studies where they may have reasonable risks and the potential for direct benefit, in additional to contributing to the knowledge to aid future patients.
[i] Informed Consent: Guidance for IRBs, Clinical Investigators and Sponsors. HHS, FDA, Draft August 2023. https://www.fda.gov/media/88915/download
[ii] https://www.hhs.gov/ohrp/regulations-and-policy/belmont-report/index.html
