Addiction 101 | CAMH

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Tolerance

When a person needs higher doses of a substance to produce the same effects they experienced during earlier use, they have developed tolerance. People often develop tolerance while they are physically dependent on a substance (Portico, 2017).

 

Withdrawal

When a person reduces or stops their substance use after a period of using regularly, they experience withdrawal symptoms. This results in unpleasant sensations and feelings.

A person’s withdrawal symptoms are opposite to the main effect of the substance used. For example:

sedative withdrawal creates hyperactivity with dangerous medical complications
opioid withdrawal includes anxiety, powerful cravings and flu-like symptoms
stimulant withdrawal consists of depression, insomnia and cravings (Portico, 2017).

 

Physical dependence

Physical dependence is a bodily state that may develop with regular drug use. It includes withdrawal symptoms and increased tolerance (Portico, 2017).

When at least three of the following occur in the same 12-month period, it is considered physical dependence (WHO, n.d.):

tolerance to the substance, specifically needing increased doses to achieve the same effects
physical withdrawal when stopping or reducing substance use
a strong desire or compulsion to take the substance
difficulty controlling substance use-related behaviours
ignoring other interests because of the time needed to get or take the substance, or recover from its effects
continuing with substance use despite harmful consequences

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Addiction 101 © , CAMH.