Tolerance

Tolerance develops when repeated exposure to a substance produces less of a particular effect, so a larger amount may be needed to produce the response that occurred before. Tolerance can develop in several ways and does not mean the substance has become safer.

Tolerance is often described as being able to “handle more”, but that can be misleading.

Repeated exposure to a substance can reduce some of its effects. The same amount may feel weaker than before, or more may be needed to produce the desired effect.

That does not mean the body has become protected from everything the substance does. Tolerance can develop unevenly. Someone may feel less intoxicated, sedated or euphoric while other effects and risks remain.

Tolerance is also different from physical dependence and addiction. It describes a changed response to repeated exposure. It does not by itself establish withdrawal risk, compulsive use or impaired control.

Tolerance can also decrease after a period of reduced or no use. Returning to an amount that was previously tolerated can then produce a much stronger effect than expected.

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