Substance misuse refers to the use of legal or illicit drugs, including alcohol and medicine, in a way that causes mental or physical damage. This may include low levels of substance use that would not usually be considered harmful or problematic, but may have a significant effect on the mental health of people with a mental illness such as psychosis.

Regularly consuming quantities of substances such as drugs or alcohol that affect your mental and physical health and your ability to do the things you need to do.

Differences in description in SNOMED/LG Standards/NHS Dictionary: Misuses drugs/drug user/substance use Alcohol abuser/alcohol abuse/substance use