The individual and the drug
Not only influences the amount or regularity with which a drug is consumed the effects it generates. Individual consumer level also plays a part. In this way, through tolerance or awareness that everyone has.
As mentioned, the effects felt on the first occasion of use, never repeated. Therefore, each subsequent use, but will have a pleasant nature will not be in the same way, neither in intensity nor in time.
In turn, the decrease in the pleasurable effects brings a feeling of discomfort for the consumer, which, through repetition, becomes more severe.
Tolerance and awareness come into play here. Tolerance refers to the lack or absence of these primary effects. Which leads to increasing doses to assimilate those effects. In this way a consumer repeated doses more frequently, because the effects are not the same. The latent risk here is to dependence.
In the case of awareness that a person has against drugs, the question is reversed. The more you consume, the more are the effects it has, so the more you use the drug, the more satisfaction to be had. Here, the greater the danger of overdose.