Classical conditioning
First, a drug user may become more tolerant to a drug if it is taken in similar surroundings (a similar setting) every time. This is because the familiar setting will bring about a compensatory response. As a result, taking the drug in similar settings will help your body tolerate the drug. Alternatively, taking the drug outside of the regular setting will make it harder (more difficult) for your body to manage its effects. For this reason, overdose is more common when a user takes a drug in a new setting.