Final answer:
The term for decreased drug response after repeated use is tolerance. Psychological dependence refers to drug craving. Hypersensitivity consists of excessive immune responses including types like immediate, delayed, and autoimmune.
Step-by-step explanation:
The term that refers to the decreased response to a drug after its repeated usage is tolerance. Tolerance occurs when a drug user requires more and more of a given drug to experience the same effects that they did initially.
This concept is critically important in the field of pharmacology and medicine as it influences how medications are prescribed and managed over time for patients. Additionally, psychological dependence refers to drug craving and the emotional need for a drug, which can contribute to the development of tolerance.
Hypersensitivity is a spectrum of inappropriate immune responses towards harmless foreign particles or self-antigens; this occurs after tissue sensitization and includes types such as immediate, delayed, and autoimmune hypersensitivities.
The maintenance of immune tolerance is the acquired ability to prevent an unnecessary or harmful immune response to a detected foreign body known not to cause disease.