How does addiction affect the body's response to drugs?

Addiction alters the body's response to drugs by increasing tolerance and dependence, leading to physical and psychological changes.

When a person repeatedly uses a drug, their body starts to adapt to the presence of the substance. This is known as tolerance. The body becomes so accustomed to the drug that it requires larger doses to achieve the same effect. This is one of the primary ways addiction affects the body's response to drugs. The body's chemistry changes to accommodate the drug, and over time, it may stop producing certain chemicals naturally because it's receiving them from the drug. This leads to dependence, where the body relies on the drug to function normally.

Moreover, addiction can also cause significant changes in the brain. Drugs often target the brain's reward system, flooding it with dopamine, a neurotransmitter associated with pleasure. This intense feeling of pleasure can lead to repeated drug use. However, with continued use, the brain adjusts to the excess dopamine by producing less of it or reducing the ability of cells in the reward circuit to respond to it. This reduction in dopamine activity can lead to feelings of sadness or depression when not using the drug, driving individuals to continue using to avoid these negative feelings.

Furthermore, addiction can also affect the body's physical health. Many drugs have harmful effects on the body's organs, particularly the liver, heart, and lungs. Chronic drug use can lead to a variety of health problems, including heart disease, liver failure, and lung disease. Additionally, the body's immune system can be compromised, making the individual more susceptible to infections and diseases.

In conclusion, addiction significantly alters the body's response to drugs, leading to increased tolerance and dependence, changes in brain function and physical health problems. Understanding these effects is crucial in the study of addiction and the development of effective treatments.