Addiction affects millions of lives in the U.S. It is a chronic disease that frequently includes cycles of relapse and remission, and it is progressive without treatment or participation in recovery work. It is characterized by being unable to consistently abstain from substance use and having cravings, impaired control of behaviors, unhealthy emotional responses, and reduced realization of significant problems.¹

It is not known exactly what causes a substance use disorder (SUD). However, factors such as genetics, substance effects, peer influences, emotional distress, mental illness, and outside stressors can contribute to the development of a SUD.²

The disease carries with it a certain shame-laden stigma, and many people do not seek help due to fear of being judged. Using problematic labels—such as calling someone with a SUD an addict—can perpetuate that stigma.³

Repeated use of dangerous drugs can physically change the brain, making it more difficult for an individual to control their behaviors and resist powerful cravings to use drugs.⁴

There are a multitude of dangerous substances in circulation. In a 2007 study, experts scored 20 substances on several factors and, amongst other things, the addictive drugs were given a mean dependence score. This dependence score was based on the perceived risks of intense pleasure, physical dependence, and psychological dependence. Let’s take a look at the 12 addictive drugs ranked highest.⁵

Amphetamines

Amphetamine is a type of central nervous system (CNS) stimulant, that gives users a burst of energy or excitability. Amphetamine causes the release of chemical messengers called dopamine and norepinephrine. It can produce many effects, including pleasure, alertness, and improved concentration, as well as dangerous effects like heart problems, paranoia, aggression, nausea, and headache. Long-term use of amphetamine, especially long-term misuse, can cause additional negative consequences such as psychosis, seizures, ulcers, and malnutrition.⁶

Tolerance can develop, requiring substance users to constantly increase their dosage to get the same effects. They may binge on amphetamine to try to stay high. Binges are often followed by “crashes” where the individual may feel extremely tired, depressed, and anxious, and may crave to use it again.⁶

Benzodiazepines

Benzodiazepines, such as Valium and Xanax, are widely prescribed to treat anxiety, insomnia, alcohol withdrawal and other conditions. Though they work well for their intended uses, “benzos” can be addictive and difficult to stop.⁷

The National Institute on Drug Abuse (NIDA) states that benzodiazepines are generally prescribed long-term because there is a high risk of tolerance, dependence, and addiction.⁷An individual who takes a benzodiazepine for more than 3 to 4 weeks and then abruptly stops it will likely have withdrawal symptoms. Using benzodiazepines long term can result in doses needing to be increased and the underlying condition worsening. Weaning off of benzos should be done gradually under the direction of a medical professional.⁸

Methadone

Methadone is a synthetic opioid that can prevent or reduce opioid withdrawal symptoms, reduce opioid cravings, and block the effects of heroin and other opioids.⁹

Methadone is generally safe and effective if taken as prescribed. However, it can be addictive, so its medical use is carefully controlled.¹⁰ Suddenly stopping methadone may cause withdrawal symptoms, such as anxiety, irritability, runny nose, sweating, chills, pain, trouble sleeping, nausea/vomiting, and diarrhea.¹¹

Nicotine

Scientific data shows that tobacco use is the leading preventable cause of preventable death in the United States. It is estimated that more than 16 million people in the U.S. have a disease that is caused by smoking.¹²

Nicotine mimics the neurotransmitter acetylcholine and binds to its receptor. The brain thinks there is too much acetylcholine present, so it reduces the number of acetylcholine receptors and reduces the amount of acetylcholine that it releases. This results in the brain needing nicotine to function normally, which can lead to addiction.¹³

Alcohol

Though legal, alcohol acts as a CNS depressant, meaning it relaxes, reduces anxiety, and impairs judgment, as well as other effects.^14,15 When someone consumes alcohol, the brain releases dopamine and endorphins, which influence motivation and the sensation of pain.

Over time, people who drink regularly need to consume more and more alcohol to get the same effects. These individuals can become dependent on alcohol, where if they stop drinking they develop withdrawal symptoms.¹⁶ Alcohol withdrawal can be life-threatening.¹⁷

Cocaine/Crack

Cocaine is a stimulant drug that causes dangerous physical effects such as euphoria, increased alertness and energy, rapid heart rate, and increased blood pressure. It can even lead to heart attacks, seizures, strokes, and/or death. Many people use cocaine in binges, where they repeatedly take the drug for a short period to stay high. Repeated use of cocaine can lead to addiction. Cocaine increases the amount of available dopamine in the brain by preventing the dopamine from being recycled back into cells. This leads the brain to adapt to the high levels and become less sensitive to dopamine, and more and more cocaine is needed to produce the same effects and prevent withdrawal.¹⁸

Made from a process involving powder cocaine and either ammonia or baking soda, crack is a version of cocaine. The key difference is that crack is usually smoked. Crack is more potent than powder cocaine, and smoking crack causes the high to be almost immediate and intense. Crack’s high is extremely short, usually around 15 minutes, often causing the user to repeatedly smoke it to stay high. Withdrawal symptoms can include immense fatigue, depression, agitation, anxiety, and strong cravings—all of which can drive a person to keep using the drug.²⁰

Heroin

Heroin is a very addictive opioid drug. Heroin can cause euphoria, altered sensation of pain, nausea/vomiting, itching, dry mouth, skin flushing, decreased consciousness, and clouded thinking. Individuals who use heroin often develop tolerance, where they need more heroin to get the same effects. Long-term use of heroin can cause many problems, such as trouble sleeping, constipation, liver disease, kidney disease, lung problems, infection of the heart valves/lining, and more. Overdosing on heroin can be fatal.²¹

The route of administration may impact heroin dependence. A study found that people who inject heroin have more severe dependence than those who smoke the drug.²²Individuals who suddenly stop (or notably decrease) regular use of opioids can go through withdrawal. Opioid withdrawal can be extremely uncomfortable but is generally not life-threatening. However, individuals may relapse to relieve withdrawal symptoms, and they can easily overdose because withdrawal decreases their tolerance. Most fatal opioid overdoses happen in people who recently detoxed.²³

Barbiturates

Barbiturates are a class of prescription medications. They are a type of CNS depressant, meaning that they can slow activity in the brain.²⁴ Barbiturates cause drowsiness and relaxation, as well as other possible side effects, and they can be addictive. Repeated use can rapidly lead to tolerance to the mood effects of barbiturates, but tolerance to the potentially fatal effects takes longer to develop. Thus, regular use increases the risk of poisoning and can be deadly. Not only can barbiturate overdose be lethal, but barbiturate withdrawal can also be life-threatening. Thus, individuals should not start, stop, increase, or decrease barbiturate use without the direction of a medical professional.²⁵

Buprenorphine

Buprenorphine, like methadone, can prevent or reduce opioid withdrawal symptoms, reduce opioid cravings, and block the effects of other opioids.^26,27However, buprenorphine is a partial opioid agonist, meaning that its effects are less powerful than full agonists like methadone or heroin. Buprenorphine also has a “ceiling effect” where, starting at moderate doses, the effects of the drug level off and do not increase with dose increases, which decreases the risk of side effects, misuse, and dependency. Buprenorphine is generally safe and effective if taken as prescribed. However, buprenorphine can be misused because of its opioid effects.²⁶ Suddenly stopping buprenorphine may cause withdrawal symptoms.²⁷

Ketamine

Ketamine is an anesthetic that can cause dissociation and/or hallucinations, as well as pain relief, sedation, memory loss, immobility, agitation, depression, trouble thinking, increased blood pressure and heart rate, nausea, and loss of consciousness. Because it has medical uses but also abuse potential, it is a Schedule III substance. Ketamine is considered a “club drug” because it is popular at “raves” and dance clubs. Overdosing on ketamine can be dangerous.²⁸

Cannabis

Cannabis (also referred to as marijuana) contains THC, a mind-altering chemical. Marijuana is legal in some states for medical uses and/or recreational use. It can cause many effects, such as feeling high, mood changes, altered senses, change in perception of time, and trouble thinking. In high doses, it may cause delusions, hallucinations, and psychosis. Long-term use of marijuana can impact brain development and cause problems with breathing, nausea and vomiting, and more. Chronic use may result in addiction, and individuals who start using marijuana before they are eighteen are even more likely to develop a cannabis use disorder. Stopping marijuana may cause withdrawal symptoms.²⁹

4-MTA

4-MTA is a synthetic derivative of amphetamine that is typically sold as tablets. Its effects are similar to those of MDMA. Users may feel peaceful, calm, and/or more empathetic, and they may have a decreased need for sleep. Possible negative effects include sweating, nausea, elevated body temperature, confusion, intoxication, dizziness, and memory loss.³⁰

Additional Highly Addictive Drugs

Because the aforementioned 2007 study only had the experts score twenty substances, countless other substances were not reviewed. For instance, methamphetamine and prescription opioids in general can each be highly addictive.

Methamphetamine/Crystal Meth

Methamphetamine is a stimulant that is typically used as a powder or pill. Crystal meth is a type of meth that can resemble glass or shiny, bluish-white rocks. Methamphetamine’s high starts quickly and ends quickly, so individuals often use it in binges, where they repeatedly use it in a short period to stay high. Other effects of meth can include increased wakefulness, fast breathing, reduced appetite, increased activity, irregular and/or fast heartbeat, raised blood pressure, and elevated body temperature. Injecting meth (or any drug) increases the risk of diseases like HIV, hepatitis B, and hepatitis C. Long-term use of meth may cause serious dental issues, significant weight loss, skin sores from scratching, confusion, trouble sleeping, anxiety, paranoia, violence, and hallucinations. Overdosing on methamphetamine can be fatal. An individual who stops using meth may experience withdrawal symptoms.³¹

Prescription Opioids

Prescription opioids are usually used to alleviate moderate to severe pain, but some can be used for diarrhea or coughing. Some common prescription opioids include oxycodone, morphine, hydrocodone, fentanyl, oxymorphone, and codeine. Prescription opioids are typically safe when used as prescribed and only taken for a short time. Individuals who use opioids as prescribed may still become tolerant of opioids and/or dependent on them if they are used regularly. This can sometimes then lead to misuse. Some people misuse prescription opioids because they can be relaxing and produce a high. Other possible effects of opioids include sleepiness, nausea, confusion, constipation, and slowed breathing.³²

Repeatedly misusing prescription opioids can result in a substance use disorder. Overdosing on opioids can be deadly.³² As mentioned previously, opioid withdrawal can be extremely unpleasant and may lead to relapse, which can easily result in a fatal overdose.²³

If you think you or someone else may be struggling with drug or alcohol addiction, reach out and get help. There are effective substance misuse treatments available. If someone has overdosed or if it is another emergency, call 911.

How to Get Help for Drug or Alcohol Addiction

If you or someone you love is struggling with substance misuse, help is available and recovery is possible. Professional treatment programs can give those battling addiction the tools needed to live happier and healthier lives. For advice on addiction and treatment options, contact an American Addiction Centers (AAC) admissions advisor at . You can also check your insurance coverage online now.

Health Insurance Providers and Coverage Levels

Visit the links below to find out more about your health insurance coverage levels, how to get your insurance company to pay for drug and alcohol rehab, and also how to pay if you don’t have insurance.

Additional Resources on Drug and Alcohol Rehab

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12 of the Most Addictive Drugs