Legal Dictionary

informed consent

Definition of informed consent

Further reading

Informed consent is a phrase often used in law to indicate that the consent a person gives meets certain minimum standards. As a literal matter, in the absence of fraud, it is redundant. An informed consent can be said to have been given based upon a clear appreciation and understanding of the facts, implications, and future consequences of an action. In order to give informed consent, the individual concerned must have adequate reasoning faculties and be in possession of all relevant facts at the time consent is given. Impairments to reasoning and judgment which may make it impossible for someone to give informed consent include such factors as basic intellectual or emotional immaturity, high levels of stress such as PTSD or as severe mental retardation, severe mental illness, intoxication, severe sleep deprivation, Alzheimer's disease, or being in a coma. This term was first used in a 1957 medical malpractice case by Paul G. Gebhard.

Some acts cannot legally take place because of a lack of informed consent. In cases where an individual is considered unable to give informed consent, another person is generally authorized to give consent on his behalf, e.g., parents or legal guardians of a child and caregivers for the mentally ill. However, in many jurisdictions, medical professionals and first responders are granted presumed consent if no-one is available to consent to lifesaving treatment on behalf of a severely injured person. That treatment can have serious consequences, as in cases of major surgery, e.g., amputation.

In cases where an individual is provided insufficient information to form a reasoned decision, serious ethical issues arise. Such cases in a clinical trial in medical research are anticipated and prevented by an ethics committee or Institutional Review Board.

Assessment of consent

Informed consent can be complex to evaluate, because neither expressions of consent, nor expressions of understanding of implications, necessarily mean that full adult consent was in fact given, nor that full comprehension of relevant issues is internally digested. Consent may be implied within the usual subtleties of human communication, rather than explicitly negotiated verbally or in writing. In some cases consent cannot legally be possible, even if the person protests he does indeed understand and wish. There are also structured instruments for evaluating capacity to give informed consent, although no ideal instrument presently exists.

There is thus always a degree to which informed consent must be assumed or inferred based upon observation, or knowledge, or legal reliance. This especially is the case in sexual or relational issues. In medical or formal circumstances explicit agreement by means of signature which may normally be relied upon legally, regardless of actual consent, is the norm.

Brief examples of each of the above:

  1. A person may verbally agree to something from fear, perceived social pressure, or psychological difficulty in asserting his true feelings. The person requesting the action may honestly be unaware of this and believe the consent is genuine, and rely upon it. Consent is expressed, but not internally given.
  2. A person may state he understands the implications of some action, as part of his consent, but in fact has failed to appreciate the possible consequences fully and later deny the validity of his consent for this reason. Understanding needed for informed consent is stated to be present but is in fact (through ignorance) not present.
  3. A person may move from friendship to sexual contact on the basis of body language and apparent receptivity, but very few people on a date that results in sexual contact have explicitly asked the other if his or her consent is informed, if he does in fact fully understand what is implied, and all potential conditions or results. Informed consent is implied (or assumed unless disproved) but not stated explicitly.
  4. A person below the age of consent may agree to sex, knowing all the consequences, but his or her consent is deemed invalid as he is deemed to be a child unaware of the issues and thus incapable of being informed consent. Individual is barred from legally giving informed consent, despite what they may feel (1)
  5. In some countries (notably the United Kingdom), individuals may not consent to injuries being inflicted upon them, and so a person practicing sadism and masochism upon a consenting partner may be deemed to have caused actual bodily harm without consent, actual consent notwithstanding. Individual is barred from legally giving informed consent, despite what they may feel (2).
  6. A person signs a legal release form for a medical procedure, and later feels he did not really consent. Unless he can show actual misinformation, the release is usually persuasive or conclusive in law, in that the clinician may rely legally upon it for consent. In formal circumstances, a written consent will usually legally override later denial of informed consent (unless obtained by misrepresentation)
  7. A person or institution (e.g., a school or childcare professional) exposes a minor to non-age-appropriate material, in any media format, without the expressed informed consent of the minor's parent or legal guardian. Informed consent in this instance goes to the argument of competency on the part of the minor. An example would be the showing of an R rated movie to a 12-year-old by an educational institution without the informed consent of the parent or legal guardian.


  1. Wiktionary. Published under the Creative Commons Attribution/Share-Alike License.


1.     lex fori
2.     landed property
3.     lex situs
4.     respondent
5.     default judgment
6.     tort law
7.     living will
8.     lex causae
9.     law
10.     salacious