Understanding Drug Use and Addiction

Most drugs affect the brain's "reward circuit," causing euphoria as well as flooding it with the chemical messenger dopamine. A properly functioning reward system motivates a person to repeat behaviors needed to thrive, such as eating and spending time with loved ones. Surges of dopamine in the reward circuit cause the reinforcement of pleasurable but unhealthy behaviors like taking drugs, leading people to repeat the behavior again and again.

As a person continues to use drugs, the brain adapts by reducing the ability of cells in the reward circuit to respond to it. This reduces the high that the person feels compared to the high they felt when first taking the drug—an effect known as tolerance. They might take more of the drug to try and achieve the same high. These brain adaptations often lead to the person becoming less and less able to derive pleasure from other things they once enjoyed, like food, sex, or social activities.

Source: Volkow et al., 2004. Dopamine in drug abuse and addiction: results from imaging studies and treatment implications. Molecular Psychiatry.

Brain scans of type-2 dopamine receptors (D2 Receptors) in the reward pathway of drug-addicted patients. These images explain part of the reason of why these individuals are dependent on these drugs. By taking these drugs repeatidly over time, their brains have responded by reducing the levels of D2 dopamine receptors in the brain's reward pathway. As a result, they are highly motivated to resume drug use in a way that a normal person might feel if they were starving for food. This experience is known as drug-craving, which is distinct from withdrawal, which is mediated by other processes in the brain.

Long-term use also causes changes in other brain chemical systems and circuits as well, affecting functions that include:

• learning
• judgment
• decision-making
• stress
• memory
• behavior

Despite being aware of these harmful outcomes, many people who use drugs continue to take them, which is the nature of addiction.

Why do some people become addicted to drugs while others don't?

No one factor can predict if a person will become addicted to drugs. A combination of factors influences risk for addiction. The more risk factors a person has, the greater the chance that taking drugs can lead to addiction.

• Biology. The genes that people are born with account for about half of a person's risk for addiction. Gender, ethnicity, and the presence of other mental disorders may also influence risk for drug use and addiction.


• Environment. A person’s environment includes many different influences, from family and friends to economic status and general quality of life. Factors such as peer pressure, physical and sexual abuse, early exposure to drugs, stress, and parental guidance can greatly affect a person’s likelihood of drug use and addiction.


• Development. Genetic and environmental factors interact with critical developmental stages in a person’s life to affect addiction risk. Although taking drugs at any age can lead to addiction, the earlier that drug use begins, the more likely it will progress to addiction. This is particularly problematic for teens. Because areas in their brains that control decision-making, judgment, and self-control are still developing, teens may be especially prone to risky behaviors, including trying drugs.
  
  
  Learn more about the known factors that influence a person's risk for developing an addiction.

Can drug addiction be cured?

As with most other chronic diseases, such as diabetes, asthma, or heart disease, treatment for drug addiction generally isn’t a cure. However, addiction is treatable and can be successfully managed. People who are recovering from an addiction will be at risk for relapse for years and possibly for their whole lives. Research shows that combining addiction treatment medicines with behavioral therapy ensures the best chance of success for most patients. Treatment approaches tailored to each patient’s drug use patterns and any co-occurring medical, mental, and social problems can lead to continued recovery.

Source: McLellan et al., 2000. JAMA, 284:1689-1695

Relapse rates for people treated for addiction are compared with those for people treated for asthma, hypertension (high blood pressure) and Type I Diabetes. Relapse is common and similar across these illnesses. Therefore, substance use disorders should be treated like any other chronic illness. Relapse serves as a sign for resumed, modified, or new treatment.

As with most other chronic diseases, such as diabetes, asthma, or heart disease, treatment for drug addiction generally isn’t a cure. However, addiction is treatable and can be successfully managed. People who are recovering from an addiction will be at risk for relapse for years and possibly for their whole lives. Research shows that combining addiction treatment medicines with behavioral therapy ensures the best chance of success for most patients. Treatment approaches tailored to each patient’s drug use patterns and any co-occurring medical, mental, and social problems can lead to continued recovery.

Points to Remember

• Drug addiction is a chronic disease characterized by drug seeking and use that is compulsive, or difficult to control, despite harmful consequences.


• Brain changes that occur over time with drug use challenge an addicted person’s self-control and interfere with their ability to resist intense urges to take drugs. This is why drug addiction is also a relapsing disease.


• Relapse is the return to drug use after an attempt to stop. Relapse indicates the need for more or different treatment.


• Most drugs affect the brain's reward circuit by flooding it with the chemical messenger dopamine. Surges of dopamine in the reward circuit cause the reinforcement of pleasurable but unhealthy activities, leading people to repeat the behavior again and again.


• Over time, the brain adjusts to the excess dopamine, which reduces the high that the person feels compared to the high they felt when first taking the drug—an effect known as tolerance. They might take more of the drug, trying to achieve the same dopamine high.


• No single factor can predict whether a person will become addicted to drugs. A combination of genetic, environmental, and developmental factors influences risk for addiction. The more risk factors a person has, the greater the chance that taking drugs can lead to addiction.


• Drug addiction is treatable and can be successfully managed.

Am I Addicted?

People struggling with addiction often are unable to recognize the disease in themselves. Unfortunately, people who compulsively seek and use drugs are mistakenly assumed to have poor judgement and lack willpower. In reality, drug addiction is a complex disease, and quitting takes more than good intentions or a strong will.

Click here to take a self-assessment to help you understand your drug or alcohol habits.

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