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The Biology of Addiction

Addiction is a long lasting brain disease:

  • The brain has a natural pleasure/reward system which helps you to repeat healthy behaviors such as exercise, eating, or bonding with a loved one.

  • Drugs of abuse disrupt this reward system by causing intense pleasurable feelings, causing you to want and use more.

  • Long time use of drugs causes the brain’s pleasure and reward system to be “hijacked” by the drugs of abuse.

  • Natural rewards such as eating may no longer activate pleasurable feelings.

  • Feelings of stress occur when the drug is not in the body.

  • Drugs also damage the prefrontal cortex, the part of the brain that helps with impulse control and decision making.

  • Certain genes are linked to addiction.

  • Teenagers’ prefrontal cortex are not fully developed, causing them to be more vulnerable to addiction.

Why do people start using drugs?

  1. To feel good

  2. To feel better

  3. To do better

  4. Curiosity

  5. Social pressures



MacNicol, Brent. The Biology of Addiction. Canadian Journal of Anesthesia. (2017) 64:141-148. DOI 10.1007/s12630-016-0771-2

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