Drug Abuse And Addiction - NIH Office of Science Education

Question 3. How may the abuse of drugs relate to the plasticityof the brain?Plasticity means that the brain can modify connections (synapses)in response to experiences. Drugs that damage or kill neurons candecrease the plasticity of the brain because neurons are not presentto form new connections and because existing connections are lost.Drugs also hijack the learning and memory systems of the brainso that cues (people, places, or things) that are associated with thedrug experience become powerful motivators of craving and druguse. In fact, addiction is sometimes described as a disease oflearning and memory.Question 4. What are some problems that scientists have when theyinves tigate the effects of drugs on the brain?Scientists have difficulty investigating the effects of drugs on thebrain because many people who abuse drugs abuse more than onedrug. Scientists must understand how each drug affects the brain andbody because drugs taken in combination may have different effects.Also, many people who abuse drugs have other medical conditionsthat make it difficult for scientists to determine what effects are dueto the drug and what effects are due to those conditions. Scientistsalso don’t know what someone’s brain was like before they used drugs.This makes it hard to determine whether drug use caused the changesor a vulnerability existed before drugs were used that made someonesusceptible to addiction.2. If students want to learn more about how drugs affect other partsof the body, encourage them to do library or Internet searches foradditional information.Because this unit focuses on the brain, it does not address how drugsact on other parts of the body. A great deal of information is availableonline. See the section Additional Resources for Teachers (page 143) forsome informative Web sites.115Student Lesson 4