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The Science Behind Drug Abuse And Addiction

Dr. Alan Weiner MD

Medically reviewed by

Dr. Alan Weiner, MD

March 18, 2019

How or if individuals become addicted to drugs or alcohol depends on a variety of factors like genetic makeup, the environment around them, and the decisions they make. The science behind addiction shows that it is more complicated than one may think.

Just as people differ in appearance due to genetic makeup, their environment, and the ways in which they care for themselves, so to do they differ in susceptibility to disease, including the disease of addiction. Addiction affects a person’s body and mind, changing chemicals in the brain, altering emotions, health, and a slew of other functions. Much like a cancer, its presence in the body eats away at one’s life and can go into remission, but is ultimately incurable.

Drug abuse and addiction can start early in life with the added influences of predisposition, emotional trauma, lack of authority, and much more. Children, teens, and adults abusing drugs habitually often become addicted to what they abuse, but it isn’t always easy to know why the drug abuse started, nor how to treat and overcome the addiction.

Some people deign to think that drug addiction is self-explanatory; they think that everyone who abuses or becomes addicted to drugs does so out of pure choice. While choice most often dictates initial actions, many times the body responds to these first, poor choices in a demanding way. This allows addiction to take control of a person: their body, their mind, their character, and even their choices. It only takes one bad choice for the doors to addiction to be thrown open. Whether the disease affects one who abuses drugs or not depends on a myriad of variables.

Consider the disease of addiction under a new magnifying glass, from the standpoint of science.


Several outcomes in who we are and what we look like can be attributed to genetic makeup. Heredity dictates whether or not we will reproduce twins just as it will determine the eye color of children. Our view of biology therefore explains that addiction as a disease is something that can be inherited and travel through generations of genetic predisposition. Though being prone to addiction does not mean we will “get it,” it still plays a part in how our bodies react to drugs, alcohol, and other, habit-forming actions and substances.

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Being predisposed to the disease of addiction can mean that shaking its hold on us is much more difficult. Treatment may work just the same as it would for others, but in those who are genetically inclined toward addiction, tolerances run especially high. With their tolerance to drugs and alcohol being greater, those affected by the disease of addiction negatively impact their bodies on a larger scale to meet their “needs” and levels of pleasure. Death and permanent damage to the mind and body may come into play more often as a result.

Long-term treatment is usually the best course of action against the disease when genetic influence can be identified. Longer stretches of treatment and therapy can help provide the tools to acquire a sober lifestyle that may not have been present for those with family-associated addiction issues.

Mental Health

While many people would like to remain certain that addiction is one very straight-forward disease, the truth is that addiction often exists alongside serious mental illness. Debilitating mental problems can not only trigger addiction to begin, but also go undetected by both those suffering from and those treating addiction.

Those who suffer from mental illness, such as depression, anxiety, OCD, or schizophrenia are at a high risk for developing an addiction to drugs or alcohol as they self-medicate their illnesses. The use of drugs and alcohol provides a false sense of relief from the symptoms of mental anguish, but as addiction sets in, drugs cause mental health problems to worsen and a cycle begins. Tolerance and dependence make the addiction contribute to the stresses they felt would be diminished by the use.

In the medical world, dual diagnosis patients—those suffering from both mental illness and addiction—need to be treated for more than just one of their ailments. Many rehabilitation centers offer programs that focus on both issues and strive to alleviate root causes and the cyclical patterns that bind these diseases to one another.

Societal Influence

Though it not a form of specific science, it can be said that the disease of addiction is often triggered simply by someone’s poor choices. Those poor choices—which tend to revolve around their environment, the people with which they associate themselves, and their general lifestyle—can quickly turn drug abuse into drug addiction. Everyone differs in their responses to the outside world as it causes an effect on their lives.

Emotion is usually the guiding force that bridges a first experience with a followup response. In simple terms: though actual peer pressure may not be contributing to one’s addiction, being around people who party hard every weekend may promote the use of drugs in someone who may not have otherwise chosen to even try drugs. Curiosity, pressure, experimentation, and thrill all go into social drug use, which can pull the user down the path to addiction.

In terms of science, when a user remains within the social surroundings that continue to promote drug use and abuse, addiction is in many instances inevitable. Binge uses and frequency of use push the body to new levels of tolerance and lifestyle change becomes imperative for any hope of recovery.

Brain Chemical Makeup

The human brain is composed of multilayered systems of communication that function in terms of what we feel, how we think, and what we do. For every function we experience, a message within the brain is sent in order for it to be orchestrated. As simple as the movement of our eyelids as they eclipse our eyes and open again, these messages are necessary for quality of life. Without this message center, transmissions would be interrupted and our bodies would remain without proper function, like those in vegetative states.

Drugs affect the brain by interfering with communications. The chemicals cause the brain to receive abnormal messages which affect normal functions, such as speech and perception. Receptors in the brain are affected by the chemicals causing releases of dopamine, which translates into the pleasurable “high” that people tend to seek.

While our brains receive false messages that produce pleasurable highs, the sensations are interpreted as “rewards” which we—in our basic human nature—continue to seek out. As our bodies grow to be used to a substance and its pleasure-inducing effects, tolerances make for the need of a higher dose. The more of a drug that we intake, the more dependent we become, the more we need, the more tolerant we are. Soon, addiction creates a need for something that is not only mental, but physical as our bodies respond to quitting too much of anything in the same way: withdrawal. Just as a hardcore carnivore would get sick if they stopped eating meat all at once, drugs leaving the body cause a sickness that is often remedied by more drug use. This deters one from quitting and continues the control addiction has on their life.

While addiction affects the brain in many negative ways that can last many years, if not a lifetime, drug use, itself, causes side effects that perpetuate more drug use. Sickness, tremors, infections, heart problems, aches and pains are just some of the bodily side effects a drug user may experience. Even more than physical issues, those addicted to drugs have undergone a change in their brain function. Chemicals alter the way we perceive many things in life, they control emotion, and they signal negative reaction. Some drugs, such as crystal meth, can cause psychosis in the mind of the user. Violence and aggression accompany drugs like these, which can overtake someone’s true personality.

Know When To Seek Help

When someone is doing any illicit drugs, it is time to make sure they’re educated and receiving help. Knowing that the user’s brain is not processing information as it normally would make it hard for them to seek out their own help. If a loved one is suffering under the control of drug abuse or addiction, contact for help getting them back to themselves.

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