A drug is any kind of substance that can cause a change in the physiology and psychology of a person when consumed. A drug user grows a tolerance as well as side effects of the drug but not at the same rate.
Drug tolerance can be defined as the reduced reaction of the drug in the body the person increases the dosage to re-amplify the effect of the drug. The drug tolerance remains for a long time till the body can sustain but later on, the side effects of consumption of overdose come into the picture, which brings drastic symptoms, which may even lead to death.
