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The Six Most Addictive Drugs & Their Side Effects

Recovery Centers of America

Authored by Recovery Centers of America

There are millions of individuals in the United States who suffer from substance use disorder. A study done by the National Center for Drug Abuse Statistics on general drug use showed that 31.9 million (11.7%) of the population over the age of 12 currently use illegal drugs, and that 20.3 million people admitted to having a substance use disorder in 2018. 

Substance use disorder can lead to overdoses and death, and the study indicates over 700,000 individuals have died from an overdose since 2000. Although President Obama proposed bills to address the opioid and heroin use epidemic, fully addressing and preventing substance misuse begins with knowledge.

By understanding how the most addictive drugs work, what they look like, the risk of dependency, and where to seek help, we can empower individuals with the knowledge to stay clear, help others who need help, or even seek out help themselves. 


Heroin is an opioid drug that is made from morphine — a natural substance produced by the poppy plant. The drug can be found as a white or brown powder, and it can also be found as a black, sticky substance. Heroin can be snorted, smoked, or injected directly into the veins. The immediate effects of heroin use include what heroin users call a “rush.” This is generally followed by a warm feeling, dry mouth, and a heavy feeling throughout your legs and arms. After the initial effects, users begin to feel drowsy as their mental function, heart rate, and breathing are slowed. 

Heroin is a Schedule I drug, which, according to the Controlled Substances Act (CSA), means:

  • The drug, substance, or chemical has a high potential for misuse;
  • The drug, substance, or chemical has no currently accepted medical use in treatment in the U.S.;
  • There is a lack of accepted safety for use of the drug, substance, or chemical under medical supervision.

Heroin use statistics show more than 300,000 people over the age of 12 reported using heroin, and overdoses from prescription opioids and heroin have risen dramatically over the years. Symptoms of heroin addiction vary, but may include:

  • Drug paraphernalia: As mentioned above, there are a few different forms of heroin and multiple ways to consume it. Take notice of pipes, spoons, needles, tinfoil, and rubber tubing/elastic;
  • Physical symptoms: Physical symptoms generally occur rapidly and include dry mouth, flushed skin, constricted pupils, falling asleep, slowed breathing, lack of control, itching, vomiting, needle marks, and constipation;
  • Lifestyle changes: Heroin can cause behavior and lifestyle changes. Look out for social isolation/withdrawal from friends and family, lack of personal hygiene, and any other things that may be out of the ordinary (e.g. wearing a long sleeve or sweatshirt on hot days).

If you are wondering if your loved one needs heroin treatment, you should pay close attention to the symptoms above and reach out to them. If an intervention doesn’t work, but the individual wants to seek help, consider researching what heroin addiction treatment entails and where to find a recovery center location


Cocaine is a neuro-stimulant drug made from plant leaves. Cocaine works within the dopaminergic system, yet also acts as a serotonin-noradrenaline-dopamine reuptake inhibitor (SNDRI). It allows the brain to take in an excess of serotonin, noradrenaline, and dopamine to create a powerful euphoria and stimulant effect. 

Cocaine can come in two forms: soap-like crystals and white powder. Cocaine and crack cocaine are two terms that are often used interchangeably. Although the two are very similar, there are differences between crack and cocaine. There are no pharmacological differences; the difference is in consumption methods. Cocaine can be snorted, swallowed, or mixed with water to create a “freebase” for injection, while crack cocaine is smoked. 

Cocaine is a Schedule II drug, which, according to the CSA, means:

  • The drug, substance, or chemical has a high potential for misuse;
  • The drug, substance, or chemical has a currently accepted medical use in treatment in the U.S. or a currently accepted medical use with severe restrictions;
  • Misuse of the drug, substance, or chemical may lead to severe psychological or physical dependence and are considered dangerous.

According to the National Institute on Drug Abuse, the scope of cocaine use in the U.S. has been relatively stable since 2009, and adults aged 18 to 25 are more likely to partake than any other age group. According to the same study, just under one million Americans were considered cocaine-dependent in 2014. Cocaine addictions can be hard to distinguish; below are some of the symptoms of cocaine use:

  • Dilated pupils;
  • Long periods of wakefulness;
  • Loss of appetite;
  • Overconfidence;
  • Over-excitement;
  • Paranoia;
  • Runny nose or frequent sniffles;
  • White powder around nostrils;
  • Legal issues;
  • Missing or being late to work;
  • Financial problems;
  • Mood swings;
  • Irritability;
  • Depression.


Nicotine is a stimulant drug that is derived from the tobacco plant. Nicotine affects everyone differently, but some common effects after consumption include mild stimulation, increased heart rate, improved concentration, relaxation, tingling, suppressed appetite, and a head rush. There are various ways to consume nicotine as well – it can be smoked, chewed, and vaped. 

Even though nicotine is considered a drug, it is not regulated or classified by the CSA. According to a study done by the Centers for Disease Control and Prevention (CDC), tobacco use is the leading cause of preventable disease, disability, and death in the U.S. The same study goes on to explain that just under 40 million adults and 4.7 middle/high school students use at least one tobacco product. As mentioned above, nicotine dependence can lead to a variety of health issues —  this includes:

  • Cancer;
  • Heart/circulatory system problems;
  • Diabetes;
  • Eye problems;
  • Infertility/impotence;
  • Pregnancy problems;
  • Prone to illness;
  • Dental issues.


Alcohol is the active chemical found in beer, wine, and other hard spirits that can cause individuals to become intoxicated. It is classified as a sedative-hypnotic drug. When it is consumed in small amounts, it can act as a stimulant. When it is consumed in large amounts, it can act as a sedative. 

Like nicotine, there is no CSA scheduling of alcohol. Regardless of classification, the physical and psychological factors of alcohol are extremely addictive. According to 2019 alcohol facts and statistics collected by the National Institutes on Alcohol Abuse and Alcoholism:

  • 85.6% of people ages 18+ have consumed alcohol at some point;
  • 25.8% of people ages 18+ have engaged in binge drinking;
  • 14.1 million people ages 18+ have an alcohol use disorder (AUD);
  • 414,000 adolescents (ages 12-17) have an AUD;
  • Around 95,000 individuals die annually from alcohol-related causes.

The effects of alcohol dependence can be broken down into two categories:

  • Short-term effects: slurred speech, drowsiness, changes in mood/behavior, impaired coordination, lower body temperature, vomiting, blackouts, loss of consciousness, comas, and death;
  • Long-term effects: increased tolerance, cardiomyopathy, arrhythmias, strokes, high blood pressure, fatty liver, alcoholic hepatitis, fibrosis, cirrhosis, cancer, and an impaired immune system.


Barbiturates are central nervous depressants that are derived from barbituric acid. There are a variety of barbiturates; examples of the prescribed names include Fiorina, Pentothal, Seconal, and Nembutal. They are created in pill form, can be broken down to snort, or mix with water for injection. 

Barbiturates are Schedule II drugs, which, according to the CSA, means that they are used in medicine, but can be highly addictive. Barbiturate-use symptoms include:

  • Increased talkativeness;
  • Elation;
  • Reduced inhibition;
  • Impaired judgment;
  • Emotional fluctuations;
  • Sedation (users may seem relaxed or drowsy);
  • Slurred speech;
  • Lack of coordination (users may fall over frequently);
  • Confusion.

There are few studies compiled on barbiturate statistics since the federal government restricted access to them in 1970, but their use is not something that should be taken lightly. Additionally, when mixed with other drugs like cocaine, heroin, meth, and opiates, it can raise concern for overdosing. Barbiturate-use side effects can include: 

  • Lightheadedness;
  • Onset dizziness;
  • Sedative effects;
  • Nausea;
  • Abdominal pain;
  • Vomiting;
  • Death.


Benzodiazepines — commonly called “benzos” — are manufactured prescription medications that slow down the central nervous system. Common examples include Xanax, Valium, Klonopin, Librium, and Ativan. They are created in pill form but can be broken down to make an injectable solution, or to snort it. They can be used for anxiety, muscle spasms, seizures, sleeplessness, alcohol withdrawal, premenstrual syndrome, and a variety of other health issues.

Benzodiazepines are a Schedule IV drug, which, according to the CSA, means:

  • The drug, substance, or chemical has a low potential for misuse and low risk of dependence compared to Schedule III substances;
  • The drug, substance, or chemical has a currently accepted medical use in treatment in the U.S.

Although the risk is considered less prevalent than with other substances, benzodiazepine addiction is a serious problem that does occur. A study from the National Library of medicine on benzodiazepine dependence shows that up to 44% of chronic users become dependent. Benzodiazepine addiction symptoms include:

  • Anxiety;
  • Depression;
  • Insomnia;
  • Increased heart rate and blood pressure;
  • Excessive sweating;
  • Hand tremors;
  • Hallucinations;
  • Seizures.

Treatment Options for Drug and Alcohol Overuse

The first step to treatment is realizing when you, or someone you care about, has a substance use disorder. It can be difficult to talk to someone who doesn’t believe they have a substance use disorder or who isn’t ready for help. An intervention can help with this. 

Additionally, professional treatment options include:

While these may be the top addictive drugs, there are other substances that can cause addiction too. If you or a loved one is suffering from an addiction, RCA can help.

Authored by

Recovery Centers of America

Recovery Centers of America



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