Tolerance: Tolerance refers to a reduced response to a drug over time, requiring higher doses to achieve the same effect. It is often seen with chronic drug use.
Addiction: Addiction is a psychological and physiological dependence on a substance or behavior. It involves compulsive drug-seeking and use despite negative consequences.
Pharmacology: Pharmacology is the study of how drugs interact with biological systems, including their effects, mechanisms of action, and therapeutic uses.