Science of Addiction – Best Explanation by Shatterproof


The initial decision to take drugs is mostly voluntary. However, when drug abuse takes over, a person’s ability to exert self-control can become seriously impaired. Brain imaging studies from drug-addicted individuals 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.

brain metabolism

Source: From the laboratories of Drs. N. Volkow and H. Schelbert

Addiction is similar to other diseases, such as heart disease. Both disrupt the normal, healthy functioning of the underlying organ, have serious harmful consequences, and are preventable and treatable — and if left untreated, can last a lifetime.

Relapse rates for drug-addicted patients are similar to other chronic diseases, such as diabetes, hypertension, and asthma. When treatment plans are not followed or do not work, the patient will relapse. Thus, drug addiction should be treated like any other chronic illness, and treatment approaches should be adjusted when the patient relapses.

Courtesy National Institute on Drug Abuse

Here are some classic signs of addiction:

  • Inability to stop using drugs
  • Poor behavioral control
  • Constant craving for drugs
  • Inability to recognize serious problems with behaviors and relationships
  • Continued drug use despite negative consequences

Like other chronic diseases, addiction often involves cycles of relapse and remission. Without treatment or engagement in recovery activities, addiction is progressive and can result in disability or premature death.

The Impact of Drugs on the Brain

Research shows that drugs interfere with the brain’s communication system.

Our brains are the most complex organs in our bodies. The brain’s communications centers consist of billions of neurons, or nerve cells. Networks of neurons pass messages back and forth to different structures within the brain, the spinal column, and the peripheral nervous system. This intricate system regulates our thoughts, emotions and everything we do. Drugs interrupt these vital communications and reduce the brain’s ability to perform basic life functions.

Research shows that drugs work in the brain by tapping into the brain’s communication system and interfering with the way nerve cells normally send, receive, and process information. Different drugs work in their own unique ways, but they are equally destructive. Some drugs, such as marijuana and heroin, activate neurons because their chemical structure mimics that of a neurotransmitter, sending abnormal messages through the brain. Other drugs, such as amphetamine or cocaine, disrupt communication channels by releasing abnormally large amounts of neurotransmitters.

How Drugs Trick our Brains

Drugs activate the brain’s reward system, producing a euphoric effect.

Despite the havoc these drugs wreak in our brains, we are likely to keep using them once the cycle has begun. That’s because most drugs directly or indirectly target the brain’s reward system by flooding the circuit with dopamine, producing a euphoric effect.

Drugs are more powerful than natural rewards because they can release two to ten times the amount of dopamine and the effects last much longer. And because our brains are hard-wired to remember and repeat activities that trigger this internal reward system, first use is often not the last. Teens are especially vulnerable to this effect because their still-developing brains are less effective at controlling powerful pleasure-seeking impulses.

Drugs Damage our Brains

Drug use compromises the long-term health of the brain and leads to addiction.

Unfortunately, a drug’s short-term pleasure comes with long-term consequences.  As drug use increases, our brains adjust to the overwhelming surges in dopamine (and other neurotransmitters) by producing less dopamine or by reducing the number of receptors that can receive signals. This means that, eventually, dopamine simply doesn’t work as well on the reward circuit of a drug abuser’s brain, and the ability to experience any pleasure is reduced. A person then takes drugs just to try and bring their dopamine function back up to normal — and larger amounts of the drug are needed to create the dopamine high, an effect known as tolerance.

Drug abuse can alter the normal concentration of another neurotransmitter called glutamate, which works on the brain’s reward circuit and strongly affects the ability to learn. As the brain tries to adapt to this change, cognitive function can be impaired. Long-term drug abuse can also cause changes in habits or non-conscious memory systems, making users more susceptible to uncontrollable cravings even when the drug is not available.

Over time, drug use and abuse severely compromises the long-term health of the brain and may lead to addiction, driving a compulsive pursuit of drugs and eroding a person’s self-control and ability to make sound decisions. This is the difficult cycle we must break.

How Drugs Affect the Teen Brain

Adolescents are at greater risk of drug abuse and addiction than the general population.

Impulsive … reckless … thrill-seeking … moody … irrational … risky …

These are words often used to describe the typical teen. That is because their young brains are essentially works in progress, undergoing massive, dramatic changes from the ages of 13 to 25 — unprecedented since their days as toddlers. This state of intense growth and transformation essentially makes adolescents more prone to drug use and abuse, and it puts them at greater risk of addiction than the general population.

During this time of rapid change and growth, outside influences on the teen brain have a powerful effect. This is especially true because the part of our brain that controls judgment and reasoning — the prefrontal cortex — is still developing. Scientists have shown that our brains don’t reach their full adult potential until our twenties. All this means that not only are the effects of drugs and alcohol on a teen’s still-developing brain more powerful, but the damage can also be more lasting.

Drugs and Our Health

The overall health implications of drug abuse on users — and on others around them — are far-reaching.

The harm caused by drugs isn’t only to our brains. Imaging scans, chest X-rays, and blood tests show the damaging effects of drug abuse throughout the body.  For example:

  • Alcohol damages the cerebral cortex (responsible for problem solving and decision-making), the hippocampus (important for memory and learning), and the cerebellum (important for movement and coordination).
  • Marijuana affects short-term memory and learning, the ability to focus attention, and coordination, as one’s heart rate and lungs; and can lower IQ if use starts as a teen.
  • Cocaine use can cause severe heart, respiratory, nervous, and digestive system problems.
  • Amphetamines can lead to high body temperature, serious heart problems and seizures.
  • New drug trends like K2/Spice, “Bath Salts” and “Molly” can be dangerous because the ingredients are inconsistent. Many contain harmful additives, resulting in emergency room admissions and even death.

Drug abuse can also cause serious health problems for people other than the user. Infants exposed to drugs in the womb can suffer from developmental deficiencies in areas such as behavior, attention, and cognition. In addition, injection drug use contributes to the spread of infectious diseases, and all drugs of abuse increase the likelihood of risky sexual behaviors that contribute to the spread of HIV/AIDS, hepatitis B and C, and other sexually transmitted diseases.

How science is helping end addiction

Scientists are using new research to break the cycle of drug abuse and addiction.

By focusing on basic biology, genetics and brain functionality, addiction scientists are improving our ability to predict and prevent drug abuse, determine optimal treatments and reduce relapse. New addiction research expands our understanding of the way addiction works on our brains and identifies many of the biological and environmental factors that contribute to the development and progression of the disease. Scientists use this knowledge to develop effective prevention and treatment programs.

When addiction research started in the 1930s, addiction was seen primarily as a moral failing rather than as a public health issue. Since then, we have made great strides in our understanding of the disease and neurobiology. There is still much to accomplish to understand the range of genetic variations and other medical consequences related to addiction. Important scientific research must continue — and expand — if we are to break addiction’s grip on our