Tolerance & dependence

Tolerance

People who are physically dependent on amphetamines usually develop tolerance to the drug, making it necessary to take more and more to get the same effect. The quantity taken can reach a stage at which no further increase in the amount taken will produce the desired effect.

Dependence

Dependence on amphetamines can be psychological or physical, or both. People who become psychologically dependent on amphetamines find that using them becomes far more important than other activities in their life. They crave the drug and will find it very difficult to stop using it.