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Medically Reviewed by Dr. Mohammed Saeed, MD.

Many people associate addictive behavior with a failure of willpower or personal strength. But anyone can become addicted to a substance, and certain drugs are highly addictive. Understanding why drugs are addictive can help us realize that addiction is a biological process, not something we can “turn on and off” at will.

How Addiction Works in the Brain

Addiction begins in the brain. Our most powerful and important organ, the brain is highly sensitive. When an individual first takes an addictive drug, the brain often experiences a rush of neurotransmitters, chemicals that are responsible for sending messages throughout the body. The most common neurotransmitter that interacts with addictive drugs is dopamine, which triggers a pleasure response. We experience a dopamine rush when we exercise or eat delicious food, for example.

When we take an addictive drug, the drug prompts our brain to release high levels of neurotransmitters like dopamine, far higher than our body can produce naturally. This flood of chemicals makes it more likely that we will want to take the drug again. If we continue to take the drug over time, our brain will gradually develop a dependence on the drug. Eventually, the brain and body reach a level of tolerance, which means an individual will need to keep taking higher levels of the drug to reach the same desired effects.

If we continue past the level of dependence, we can develop an addiction. At this point, the brain and body experience strong cravings for the drug. Individuals are willing to neglect personal and professional relationships, risk financial or emotional repercussions, or even break the law in order to fuel their addiction.

Individuals with a genetic predisposition to addiction, as well as those struggling with traumatic stress, mental health issues, poverty, abuse, and relationship challenges, may be at a higher risk for addiction than others without these risk factors. But addiction does not discriminate, and anyone can develop a drug addiction.

Why Certain Drugs Trigger Addiction More Easily Than Others

Addiction can take many forms. Even over-the-counter medications can become habit-forming and addictive. But there are particular types of drugs that trigger addictive behaviors more easily than others. These are typically stronger, more potent versions of drugs and are designed to rapidly change the brain and body’s chemistry. Sometimes these changes are intended to be pleasurable and relaxing, as with alcohol, while other times these changes help combat pain, increase focus, or lessen depression. These highly addictive drugs include:


  • Because of its highly addictive properties and legality, alcohol is one of the most popular addictive substances nationwide. Like many other drugs, alcohol causes the brain’s neurotransmitter activity to increase, especially levels of dopamine and serotonin. These two chemicals cause the “buzz” associated with alcohol, where individuals feel calm, sedated, or a sense of pleasure. This reaction is relatively short-lived, however, and can easily trigger a pattern of frequent drinking.

Opioids (including fentanyl, heroin, and prescription medications)

  • Commonly used to manage chronic or extreme pain, opioids are highly potent painkillers. In order to accomplish this goal, these drugs are designed to block the body’s pain sensations while boosting the level of dopamine and other neurotransmitters to create a sensation of calm and pleasure. As with many drugs, this unnaturally high level of neurotransmitter chemicals can prompt the brain and body to develop cravings for the drug very quickly.


  • Doctors often prescribe benzodiazepines to patients who are struggling with anxiety or having difficulty falling asleep. These drugs slow down the body and brain and must be very carefully managed by the doctor who prescribes them. They are generally not intended for long-term use. The reason for this caution is their high level of addictiveness, which is caused when the brain releases dopamine during their use. Ongoing research suggests that equivalent levels of dopamine are released when an individual takes a benzodiazepine as when they take an opioid drug.


  • For patients who need help with focus and concentration, doctors often prescribe prescription stimulants. These drugs increase the body’s heart rate, breathing, and blood pressure and help individuals with attention-deficit or memory-related challenges. Unfortunately, when used improperly, they can become highly addictive as they also release dopamine during use. A non-prescription stimulant is the illegal street drug cocaine, one of the most addictive illegal drugs due to the extremely high levels of dopamine it produces.

If you or a loved one are struggling with addiction, please seek help from an addiction treatment professional.


Dr. Mohammed Saeed, MD.

Dr. Saeed is a psychiatry specialist with over 40 years of experience in the medical field. He received training in General Psychiatry at the University of Texas Medical Branch, where he was selected as the Medical Director of the Division of Child and Adolescent Psychiatry. He currently serves as the medical director at Into Action Recovery Centers. Full Bio

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