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Ethical considerations when assessing capacity to consent among individuals with problematic substance use


In BC, the law states that all persons over the age of 18 have the right to consent to health care unless they demonstrate that they are incapable of making a rational decision for themselves. Individuals with problematic substance use, and who are homeless or under-housed, have greater health needs than the general population. Clinicians who deliver care to these individuals are often unsure whether their clients have the capacity to consent for health care.


A recent study was conducted by Darlene Taylor and others [1] to determine what street outreach nurses currently do to assess their clients for capacity to consent. The study involved interviewing 19 nurses who deliver care to individuals with problematic substance use, and who are homeless or under-housed. These interviews, in combination with the medical literature, have provided important information about ethical factors that should be considered when delivering care to this population.

Implications for practice

Probably the most important ethical consideration is the assumption of capacity. In a nurse-client encounter, it is important for the nurse to assume that the client has the capacity to consent until the client demonstrates otherwise. This may be difficult for some nurses, especially if they have previously delivered care to the client and the client has demonstrated impaired decision-making capabilities.

A second consideration is the element of justice. This refers to the fact that all clients, even those who struggle with substance misuse, have the same rights to health care and the same rights to consenting for health care.

A third consideration is respect for the client’s environment, especially if care is being delivered in outreach settings such as on the street, in an alley, or in a single room occupancy hotel. When delivering care in a clinic, consent may be implied because the client has entered the clinic for a reason. This is an indication that the client is consenting for care. However, street nurses should consider who initiated the outreach encounter – the client or the nurse. If the nurse has initiated the encounter, implied consent cannot be assumed.

During a health care encounter, consent may be verbal, but it must be informed. This means that the client should be given information about the care being offered that would be considered sufficient for any reasonable person to understand. In addition, clients should also be given enough time to reflect on this information, so they can make an autonomous decision without being influenced by others. In a nurse-client encounter, there is a natural power imbalance. However, it is important for nurses to avoid misuse of this imbalance to persuade the client to agree to an intervention that the nurse feels may be of benefit.


Providing care to individuals who may or may not have the capacity to consent for care can be challenging for nurses, especially when delivering care in street outreach settings. An assessment of capacity is necessary prior to delivering care and should be done in the context of the ethical considerations discussed.

Further information

For more information about this study please contact Darlene Taylor, PhD candidate.


  1. Taylor D, Masse L, Ho, A, Rekart ML, Tyndall M, Henry G, Clifton J, Peters L, Ogilvie G, Buxton J. A brief tool to assess capacity to consent for medical care among homes individuals with problematic substance use: study protocol. Arch Public Health 2013;71(1):11.