How to conduct research involving people who may not have capacity to consent for themselves

Over 2 million people in the UK have significantly impaired decision-making capacity. This may be due to conditions such as dementia or stroke. Including this population in health- and social-care research is vital to ensure they receive evidence-based care, but the ethical and legal requirements involved can make this daunting. As a result, researchers may exclude people who cannot give consent to take part in research, even from studies that are relevant to them. Better preparation at the planning stage of a study can help ensure that it is more inclusive of people with additional decision-making needs.

So, what do researchers need to do? 

First, think carefully about who to include in your study. The underlying principle is that every individual has a right to be offered the chance to take part in research. But if your research is relevant to particular groups, you should be specifically including them. 

Then, consider whether any of these groups are likely to include people who may not have capacity to consent for themselves. This might include people living with neurodegenerative conditions or profound learning disabilities. Remember that people with the same diagnosis are diverse, so some people from a particular group may be able to consent for themselves while others cannot.

Next, think through how to ethically include these groups in your research. 

To help with this final consideration, we offer five practical tips on conducting research involving people who may not have capacity to consent, based on recent research. 

1. Design in inclusivity

Ensure that all aspects of your study, from the eligibility criteria to data-collection procedures, are designed so that people with additional decision-making needs have the opportunity to take part. This includes people who might need extra support or adjustments in order for them to be able to understand information about the study, make a decision about taking part and express that decision (either verbally or non-verbally). There are tools available to help you assess a person’s communication needs, such as the Consent Support Tool, and there is a legal test for assessing capacity to consent if you have concerns about this. Tools such as the INCLUDE Impaired Capacity to Consent framework can help with designing an inclusive study. 

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People must be supported to provide their own consent where possible. Do not assume who can give consent for themselves. Identify what reasonable adjustments may help, as well as what alternative consent arrangements may be needed for those who do not have capacity to consent for themselves. 

Conducting inclusive patient and public involvement activities with diverse people from the groups you’re including (and carers where appropriate) is vital when planning your study to help understand what needs people may have and how to meet them. 

2. Optimise consent and supported decision-making processes

All relevant information about a study should be provided in an accessible format. For example, you may need to provide pictures to support the text, use a larger font size or create easy-read versions. Think about digital access when providing information online, and consider people who use languages other than English. 

Providing accessible information and other support can maximise people’s ability to provide their own consent or express their wishes about taking part. There are lots of resources available on accessible design, supporting people with communication disabilities, and how to assess a person’s capacity if required. 

Remember that capacity to consent is specific to a particular decision and may change over time. Just because someone lacked capacity to consent on one occasion does not automatically mean they will lack capacity to consent on another. Make plans in your project for when a person’s capacity may fluctuate so you are prepared if this does happen. For example, you could ask them to nominate who they would like to represent their wishes should they lose capacity at any point. You do not have to assume that if someone loses capacity they must withdraw all their data from a research project.

3. Check what ethical and legal requirements apply

To ensure you have appropriate approvals in place for including people who do not have capacity to consent, check what ethical and legal requirements apply. This might depend on your research type and recruitment locations. Different mental capacity laws apply in England and Wales, Scotland and Northern Ireland, for example, although many key principles are the same. 

Studies involving people who lack capacity to consent require review by an appropriate research ethics committee (REC) to ensure all relevant ethical and legal requirements are being met. The REC also considers any risks and benefits for participants, and makes sure participants’ safety is protected.

You can find full details of the requirements and processes on the Health Research Authority website and access top tips on applying for REC approval. We also suggest contacting your research office for advice. 

4. Consult with others 

Before including someone who lacks capacity to consent in a study, you will need to involve another person in the decision about whether they take part or not. This is usually a family member or friend. You will need to inform the family member or friend about the study and ask what they think the potential participant’s views would be about taking part. 

Meaningfully involving the potential participant themselves in the decision is essential, and if they indicate that they don’t wish to be in the study, you should not include them. The Health Research Authority website and ASSENT guidance provide more information and examples to help with this.

5. Consider undertaking additional training 

You may wish to undertake additional training in how to conduct research involving people who lack capacity to consent. You may have access to locally run courses or to online courses that are available through the National Institute for Health and Care Research or CONSULT e-learning.

People who may not have capacity to consent for themselves shouldn’t be excluded from research that is relevant to them. Many resources are available to help you to ethically include this population in research and ensure that people’s rights and interests are respected.

Victoria Shepherd is a principal research fellow at Cardiff University. Anna Anderson is a research fellow in qualitative research and Amy M. Russell is an associate professor of health inequalities, both at the University of Leeds.

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