• I understand the effects of habituation, and therefore I shall exercise caution and significantly reduce the quantity of any familiar drug I use when taking the drug in a new and different environment for the first time.

This caution is warranted due to the effects of habituation, a form of conditioning not isolated to drug use. The basic theory goes that the environment in which one is accustomed to using a drug eventually stimulates the compensatory response your body makes to the drug. In the absence of the environment as a stimulus, the effect of the drug will then be much greater than one expects. Studies have shown, for example, that most heroin overdoses occur when an addict does his or her normal dose in an unusual environment. For example, someone accustomed to shooting up in their own home might O.D. if they shoot up in the park, even with their normal dose.