Long Term effects of drugs on the brain

1. Long Term effects of drugs on the brain

2. 1) What are some of the ways that drugs cause long-term changes in the brain? • The continued use of drugs may cause the brain to become resistant to the effects of the drug (tolerance).

3. What is drug tolerance? When a higher dose of a drug is needed in order to get the same effect as the first time it was used. Why does drug tolerance develop? 1) The body may become more efficient at eliminating the chemical (drug) from the body 2) The cells of the body and brain become less responsive to the effect of the drug.

4. 1) What are some of the ways that drugs cause long-term changes in the brain? • Some drugs, such as alcohol and MDMA, can kill brain cells.

5. Why are large amounts of alcohol bad for the brain? • In large doses, alcohol kills neurons in 2 specific brain areas: • the mammillary bodies (important for memory) • the cerebral cortex (controls mental functions)

6. How does MDMA (ecstasy) affect the brain? • It kills neurons that produce serotonin • Serotonin= a neurotransmitter involved in regulating appetite, sleep, emotions.

7. 1) What are some of the ways that drugs cause long-term changes in the brain? • Cocaine can cause the activity level of the brain to decrease for a long period of time after drug use is stopped.

8. How does cocaine affect the brain? • It reduces glucose metabolism up to three months after the last use of the drug • This indicates that the neurons of cocaine addicts are less active 3 months after they have stopped using the drug

9. 3) How may the abuse of drugs relate to the plasticity of the brain? • Plasticity means that the brain can modify connections (synapses) in response to experiences. • Drugs that cause neuronal death can decrease the plasticity of the brain because neurons are not present to form new connections and because existing connections are lost.

10. Summary: Drugs Change Brain Chemistry! • Long term drug abuse and addiction lead to changes in the brain’s anatomy and chemistry • Loss of neurons in hippocampus results in memory loss • Decrease in glucose metabolism results in a reduction of the brain’s processing abilities • These changes in the brain cause drug addicts to loose the ability to control their drug use

11. Drugs impact more than just the brain • Addiction changes all aspects of an addict’s life. • Drug addicts will: • Become isolated from family and friends • Have trouble at work or school • Potentially get involved in theft and violence

12. Drug Addiction: A Disease?

13. What is a disease? • A disease is an abnormal condition affecting the body of an organism. • In humans, "disease" is often used more broadly to refer to any condition that causes pain, dysfunction, distress, social problems, and/or death to the person afflicted

14. So, is drug addiction a disease? • Despite what many people may think, drug addiction is, in many ways, similar to other chronic diseases such as diabetes and coronary artery disease • Genetic, environmental, and behavioral components contribute to each of these diseases. • Some people may argue that drug addiction is different because it is “self-inflicted” but voluntary choices do contribute to the onset or severity of other chronic diseases as well. • For example, a person who chooses to eat an unhealthy diet and not exercise increases his or her risk for coronary heart disease.

15. Can we cure drug addicts? • No cure is available, but addiction can be treated effectively. • Treatment is effective when the addict follows the prescribed treatment regimen (usually involving but not limited to): • reducing or abstaining from drug use • improving his/her personal health and social function • Attending behavioral therapy • Taking medication

16. Pharmacological treatment of drug addiction • Heroin addiction can be treated with methadone • Methadone prevents craving and withdrawal symptoms

17. How does methadone work? • Methadone is an opiate receptor agonist • It binds to the same receptor as heroin, but does not cause activation of the neuron (no AP is fired, thus no high is achieved) • Heroin cannot produce a high when methadone is in the blood, occupying opiate receptors

18. Naltrexone • Naltrexone is also used to treat heroin addiction; however, it’s mode of action is different than methadone • Naltrexone is an opioid receptor antagonist • Instead of competing with heroin (to bind to a receptor), naltrexone prevents heroin from binding to the receptor, thus preventing heroin from eliciting it’seuphoric high

19. Is pharmacological therapy enough to treat drug addiction? • No, pharmacological therapy alone is not sufficient to treat addiction • Behavioral treatment in combination with pharmacological treatment is the most effective way to treat drug addiction

20. Is treating a disease an easy task? • Adhering to a treatment plan is difficult, not only for drug addicts, but for anyone with a chronic disease. • Less than 50 percent of diabetics follow their routine medication plan, and only 30 percent follow their dietary guidelines. • Problems adhering to a treatment plan lead to about 50 percent of diabetics needing to be treated again within one year of diagnosis

21. Is treating a disease an easy task? • Treatment for drug addiction is statistically more successful than treatment for chronic diseases, however, drug addicts commonly have relapses during treatment and recovery and begin using drugs again. • The difficulties in following a treatment plan and coping with the stresses of a chronic disease illustrate how difficult changing human behavior is

22. Medications to treat addiction- a difficult task • The development of medications to treat addiction has been difficult because the brain is such a complex organ. • When scientists better understand how drugs affect the chemistry of the brain they will then be able to develop medicine to treat drug addiction.

23. 4) What are some problems that scientists have when they investigate the effects of drugs on the brain? • Scientists have difficulty investigating the effects of drugs on the brain because many drug abusers abuse more than one drugand drugs taken in combination may have different effects than drugs taken independently. • Also, many drug abusers have other medical conditions that make it difficult for scientists to determine what effects are due to the drug and what effects are due to the other medical problem.

24. 2nd Unit Test: Wed, Nov 9 • The dose change’s the drug’s effects: • Routes of administration: inhalation, injection, snorting/ snuffing, ingestion • How do drugs get into the blood stream? And how does this effect the onset of the high and the intensity of the high • What is drug threshold? • Drug abuse and addiction: • What is a drug? • What are different classes of drugs and examples of drugs in each class? • What are the 3 types of substance abusing behavior and characteristics of each? • When does abuse become addiction? • What are factors that increase likelihood of addiction? (game, case study) • Short term vs. long term effects of drugs on the brain. • Is drug addiction a disease? • How is drug addiction is similar to other chronic diseases? • How is drug addiction treated? • How do methadone and naltrexone work at the level of neurons and their receptors? • Why is it difficult to study drug addiction and to develop medications to treat addiction?