People of all ages and at all levels of society use substances for various reasons. However, just because a person may use a substance does not mean that the person has a substance-related problem or disorder. There are many factors that determine when the use of a substance is a problem. 

There are many types of substances, which can be legally purchased, such as alcohol, tobacco, prescription and non-prescription (over-the-counter) drugs, caffeine, solvents, inhalants, as well as illegal drugs, such as cocaine.

Both legal and illegal substances may alter a person’s mood and/or behaviour.  Not everyone will have the same signs and symptoms. The effect the substance has may depend on the way it is ingested, the age and/or strength taken and the mood of the person when the substance is taken. 

People who regularly use one substance are more likely to use others as well. The use of more than one substance at the same time may alter the effect of the substances.