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[L. substantia, being, essence, contents]

1. Material; matter. SEE: 2. Substantia.
3. A chemical or drug.
4. When used in a medicolegal context, a chemical with potential for abuse. A great variety of entities are included: alcohol, nicotine, caffeine, sedatives, hypnotics, anxiolytics, and illicit drugs such as cannabis, heroin, or methamphetamines. Almost any substance may be abused even though its clinical use is approved when used as prescribed.

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