Definitions of substance abuse vary and have changed over time. However, this is the most well known definition and the definition for which the term should be used.

Substance abuse refers to the use of substances when said use is causing detriment to the individual's physical health or causes the user legal, social, financial or other problems including endangering their lives or the lives of others. Substance abuse is not specific to illegal substances but people can also abuse legal substances which are bought or prescribed. Substance abuse is an old fashioned term for which the term problematic substance use is now more widely used.

Other terms

Other terms associated with substance abuse are substance use, substance misuse, problematic substance use, substance dependancy, substance addiction, drug use, drug abuse, drug dependancy, drug addiction, alcohol use, drinking, taking drugs, using drugs/substances, on a prescription, getting drunk, getting high, etc.

'Substance use' basically means the use of any substance. This substance could be legal or illegal. The substance could be used in any manner of different ways such as sniffing, inhaling, swallowing, drinking, smoking or injecting.

Substance misuse is a fairly modern term. It is used to mean the using of substances in a manner for which they were not intended. A good example of this would be using prescription medication differently to the way a doctor has directed. This could mean taking more tablets per hour than the doctor has directed or taking the substance into the body in a different way than directed by a doctor e.g injecting tablets rather than swallow as directed.

Substance use can become abuse or problematic use when it starts to cause the substance user medical, legal, social, economic etc. problems.