What Causes Addiction?

DIRECTIONS: Read the text passage and study the diagrams below to learn how drugs such as opioids change the way the brain works. Then, use the information along with what you learned in the article to answer the questions that follow.

DRUGS AND THE DBRAIN

Drugs affect the way signals are sent in the brain's reward circuit, which is a network of structures that is activated when you do something pleasurable.

Dopamine is a chemical that helps signals pass between nerve cells in the brain. When you do something enjoyable, such as eating chocolate, dopamine levels increase in the brain (see top diagram). Receptors detect the rise in dopamine, which helps your brain remember the pleasurable behavior so that you are more likely to want to do it again.

Using drugs, including opioids, causes a rise in dopamine levels that is far greater than the increase from other enjoyable activities (see bottom diagram). When drugs are misused over time, the brain becomes used to the extreme surge of dopamine that drugs deliver. This leads to powerful cravings that make it very difficult to stop. The state of being ruled by these cravings is addiction.

THINK IT THROUGH

Use a separate sheet of paper to record your answers to the questions below.

1. What is dopamine? What role does it play in the brain?

2. Why...