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The Brain on Drugs: The Science of Addiction

October 24, 2014  |  Falmouth Enterprise

Dr. Michael Bihari

In an introduction to the recently published online booklet Drugs, Brains, and Behavior: The Science of Addiction, Nora D. Volkow, MD, Director of the National Institute on Drug Abuse (NIDA)’ noted that “For much of the past century, scientists studying drug abuse labored in the shadows of powerful myths and misconceptions about the nature of addiction. When scientists began to study addictive behavior in the 1930s, people addicted to drugs were thought to be morally flawed and lacking in willpower. Those views shaped society’s responses to drug abuse, treating it as a moral failing rather than a health problem, which led to an emphasis on punishment rather than prevention and treatment.” 

Dr. Volkow went on to say that “As a result of scientific research, we know that addiction is a disease that affects both the brain and behavior.”

The following information is from Drugs, Brains, and Behavior: The Science of Addiction. The complete text can be found at: www.drugabuse.gov/publications/drugs-brains-behavior-science-addiction.

What is drug addiction? NIDA defines addiction as a chronic, relapsing brain disease characterized by compulsive drug seeking and use, despite harmful consequences. Addiction is thought to be a brain disease because drugs change the structure of the brain and how it works. These changes in the brain can be long-lasting and can lead to harmful behaviors seen in people who abuse drugs.

Addiction is similar to other chronic diseases, such as type 2 diabetes. Both disrupt the normal, healthy functioning of the body, have serious harmful consequences, and are preventable and treatable.

Why do people take drugs? People begin taking drugs for a variety of reasons:

To feel good. Most abused drugs produce intense feelings of pleasure and, for example, the euphoria caused by opiates such as heroin is followed by feelings of relaxation and satisfaction.

To feel better. Some people who suffer from social anxiety, stress-related disorders, and depression begin abusing drugs in an attempt to lessen feelings of distress.

To do better. Some people feel pressure to enhance or improve their cognitive or athletic performance by using drugs.

Curiosity and "because others are doing it." Teens are particularly susceptible because of the strong influence of peer pressure. And, teens are more likely than adults to engage in risky behaviors to impress their friends and express their independence from parental and social rules.

If it feels good, what's the problem? When they first use a drug, people may perceive what seem to be positive effects; they also may believe that they can control their use. However, drugs can quickly take over a person’s life. Over time, if drug use continues, other pleasurable activities become less pleasurable, and taking the drug becomes necessary for the user just to feel “normal.” 

Even relatively moderate drug use poses dangers. Consider how a social drinker can become intoxicated, get behind the wheel of a car, and quickly turn a pleasurable activity into a tragedy that affects many lives.

Is continued drug abuse a voluntary behavior? The initial decision to take drugs is typically voluntary. However, with continued use, a person’s ability to exert self-control can become seriously impaired; this impairment in self-control is the hallmark of addiction. Brain imaging studies of people with addiction show physical changes in areas of the brain that are critical to judgment, decision making, learning and memory, and behavior control. Scientists believe that these changes alter the way the brain works and may help explain the compulsive and destructive behaviors of addiction.

Why do some people become addicted to drugs, while others do not? No single factor determines whether a person will become addicted to drugs.

As with other chronic diseases, drug addiction differs from person to person, and no single factor determines whether an individual will become addicted to drugs. In general, the more risk factors a person has, the greater the chance that taking drugs will lead to abuse and addiction. Protective factors, on the other hand, reduce a person’s risk of developing addiction. 

Risk and protective factors may be either environmental (such as conditions at home, at school, and in the neighborhood) or biological (for instance, a person’s genes, their stage of development, and even their gender or ethnicity).

Risk factors for addiction include: aggressive behavior in childhood, lack of parental supervision, poor social skills, drug experimentation, availability of drugs at school, and community poverty

Protective factors for addiction include: good self-control, parental monitoring and support, positive relationships, academic competence, school anti-drug policies, and neighborhood pride.

The home environment, especially during childhood, is a very important factor in subsequent drug use. Parents or older family members who abuse alcohol or drugs, or who engage in criminal behavior, can increase children’s risks of developing their own drug problems, while parents who take a strong position against drug use can decrease a child’s risk of addiction.

Friends and acquaintances can have an increasingly strong influence during adolescence. Drug-using peers can sway even those without risk factors to try drugs for the first time. Academic failure or poor social skills can put a child at further risk for using or becoming addicted to drugs. 

Scientists estimate that genetic factors account for between 40 and 60 percent of a person’s vulnerability to addiction; this includes the effects of environmental factors on the function and expression of a person’s genes. A person’s stage of development and other medical conditions they may have are also factors. Adolescents and people with mental disorders are at greater risk of drug abuse and addiction than the general population.

Other factors that increase the risk of addiction include: 

Early Use. Although taking drugs at any age can lead to addiction, research shows that the earlier a person begins to use drugs, the more likely he or she is to develop serious problems. 

Method of Administration. Smoking a drug or injecting it into a vein increases its addictive potential. Both smoked and injected drugs enter the brain within seconds, producing a powerful rush of pleasure.

Brain Maturation. One of the brain areas still maturing during adolescence is the prefrontal cortex—the part of the brain that enables us to assess situations, make sound decisions, and keep our emotions and desires under control. The fact that this critical part of an adolescent’s brain is still a work in progress puts them at increased risk for making poor decisions, such as trying drugs or continuing to take them. Also, introducing drugs during this period of development may cause brain changes that have profound and long-lasting consequences.

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