drug disposition tolerance, behavioral tolerance, and pharmacodynamic tolerance, and provide reasons why these concepts should be taken into account when determining the effects of a drug.
Drug tolerance involves both psychological and physiological factors. Physiological tolerance occurs when a subject's reaction to a specific drug and concentration of the drug is progressively reduced, requiring an increase in concentration to achieve the desired effect.
Of course, drug disposition tolerance is very concerning as addicts get used and accustomed to the drugs and the impact is not as strong as it was to begin with. This drives them to seek ever greater quantities or purity of the drug in question which of course exacerbates both their addiction and their situation.
Drug disposition tolerance occurs when more enzymes synthesize in the presence of the drug in question (precursor inhibitors are removed). This leads to rapid deactivation or excretion. This enzyme synthesizing process, and an increase therein, is what leads to the need for an increase in the amount of the drug to achieve the past/desired effect.
Behavioral tolerance is when a person learns how to behave differently to compensate for the effects of the drug. It is a learned thing. Drug disposition tolerance is physical, not learned. It is when the body neturalizes and/or excretes the drug more rapidly when the drug has been administered a number of times. In both cases, higher doses may be needed.