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The World’s Most Addictive Drugs

The World’s Most Addictive Drugs
Written by Seth Fletcher on March 24, 2020
Medically reviewed by Dr. Chintan Shah
Last update: July 24, 2023

Drug addiction is a severe problem affecting millions of people worldwide. Approximately 21% of the Canadian population (six million) will experience a substance abuse disorder or addiction at some point in their lifetime. Drug addiction is often wrongly perceived as the result of recklessness, poor judgment, and moral failure. In reality, the most addictive drugs have profound biochemical effects that make us want to use them over and over. So many people become addicted to these potent substances before they realize it. 

Family, friends, and caregivers need to understand that an addict’s compulsive need to use these substances despite their harmful effects is primarily driven by the substance and not necessarily the addict’s fault. Our CCFA guide examines the world’s most addictive substances, why they are so addictive, and how to get help from addiction.

Key Takeaways

  • Drug addiction is a brain disorder that affects millions of people worldwide; a drug addict  finds it challenging to stop using a drug despite obvious negative substances.
  • Drug addictions have behavioral, emotional, and physical consequences.
  • Drug addiction does not only affect the addict; an addict’s friends and family may also experience the financial, legal, and emotional impacts of their addiction. 
  • An addict is likely to become more successful in overcoming their addiction if they’re willing to commit to the recovery process. 
  • Drug addiction treatment typically involves a multifaceted approach that may involve detoxification, therapy, rehab, medication, and support. 

What is Drug Addiction?

Drug addiction is a complex neurobiological disease that makes a person unable to stop using a substance despite obvious adverse consequences. It is considered a brain disease because it alters brain structure and functionality. There is no single reason why people do drugs or become addicts, but addiction will typically start as an experiment in a social setting that soon becomes a habit. Not all addictions are drug-related; behavioral addictions occur when an individual becomes dependent on a particular behavior or activity, like gambling, sex, food, or compulsive shopping. 

Addictive drugs affect how we feel, and many people enjoy the instant pleasure these substances bring. In many cases, the user will become obsessed and desire to experience this euphoria again. With continued use, the individual starts to feel like they cannot function normally without the substance and become addicted. Drug addiction can have far-reaching personal, professional, emotional, and financial consequences. 

The stigma attached to frequent drug use makes many people hide their condition till it becomes a full-blown addiction. A three-stage cycle typically characterizes drug addiction: 

  • The intoxication stage

The individual uses an intoxicating drug that floods the brain with dopamine which regulates pleasure and satisfaction. Dopamine is released whenever the brain is expecting a reward. 

  • The withdrawal stage

After the pleasure wears off, the individual begins to experience a negative emotional state, lower than before using the drug. They may also experience some physical symptoms in this stage.

  • The anticipation stage

The negative emotional state makes the individual engage in drug use again to experience the high of intoxication again. The cycle continues, making the desire for the high stronger and will lead to addiction if not handled. 

Individuals become addicted at different rates depending on their environment and access to the addictive substance. While some people can become addicted to a substance within a few days, others can take months to years to become addicts. 

The consequences of drug addiction progress with time and can be fatal if not treated. 

Not every addiction looks the same, but there are general ways to identify drug addiction in an individual. If you notice these behaviors in your loved one, it may be time to help them seek help. 

  • Loss of control
  • Loss of interest in work, hobbies, study, or activities that were once enjoyable
  • Taking risks to obtain the addictive drug
  • Changes in sleep patterns
  • Social withdrawal, isolation, and secretiveness about whereabouts and activities.
  • Legal problems
  • Unexplained spending and financial problems
  • Blame shifting and diversion
  • Inappropriate, obnoxious, and childish behavior
  • Going out of one’s way to hide the amount of drug used

Are you or your loved one struggling with a drug addiction and need help? Call 1-855-499-9446 now and get the help you or your loved one needs, or request a call, and we will take care of the rest.

3 Signs of an Addiction

No one can hide a drug addiction forever, but it helps to detect drug addiction on time so you can help the individual get the help they need. The common signs of drug addiction may be behavioral, emotional, or physical. Behavioral signs involve the individual’s relationship with others; emotional signs refer to their state of mind, while physical signs are the body’s manifestation of side effects caused by drug addiction. 

Behavioral Signs

  • Obsessive thoughts of the drug and accompanying reckless actions to obtain it
  • Loss of control even when the person tries to stop using the drug
  • Denial of addiction or concealing drug use

Emotional Signs

  • Irritability 
  • Loss of interest in family, friends, and activities
  • Confusion and disorientation
  • Justifications and rationalization for drug use

Physical signs

  • Bloodshot eyes
  • Enlarged or smaller pupils
  • Sudden weight gain or loss
  • Slurred or uncoordinated speech
  • Poor hygiene and an unkempt appearance
  • Poor physical coordination
  • Insomnia or oversleeping 

The 15 World’s Most Addictive Drugs


Heroin is an opiate derived from morphine and extracted from the poppy plant. It comes as a white or brownish powder or a black sticky substance known as “black tar heroin.” Heroin is popular among drug users and goes by several street names like Chiva, Big H, Hell Dust, Thunder, and Smack. 

Heroin may be injected or smoked while purer forms are snorted. Using heroin brings on initial euphoria, followed by a twilight state or drowsiness and nausea. Heroin is highly addictive, and people can find it difficult to stop after just one use. Addicts tend to inject the drug into their veins and share needles, putting them at risk of diseases like hepatitis and HIV. It is often cut with other drugs, and users are frequently unaware of how much they’re consuming, increasing the risk of overdose. 


Cocaine is a white, crystalline powder obtained from the leaves of the coca plant. It is highly addictive and goes by many street names, including Coke, Coca, Soda Cot, Rock, Flake, and Crank. Cocaine is snorted or dissolved in water and injected. 

Cocaine is a stimulant that produces a euphoric feeling of power and energy that wears off quickly. The user soon becomes depressed and craves more of the drug to feel that high again. Cocaine is so addictive that it’s possible to become hooked after one use. It increases the heart rate, temperature, and blood pressure and puts users at risk of heart attack, stroke, and death. 


Nicotine is the addictive component of cigarettes, cigars, vaping devices, and other tobacco products. It is obtained from the leaves of the tobacco plant or produced synthetically. Nicotine may be smoked, inhaled, or chewed.

Nicotine is a highly addictive stimulant that is difficult to quit, especially for people who start using it as teens. Like other addictive substances, it floods the brain reward system with dopamine making the user crave more. Nicotine causes rapid heartbeat, increased blood pressure, shortness of breath, and a higher likelihood of lung diseases, heart disease, and stroke.


Barbiturates are a class of depressant drugs usually prescribed for anxiety, insomnia, and seizures. Examples include phenobarbital, amobarbital, secobarbital, and pentobarbital. They go by several street names like Barbs, Goof Balls, Red Devils, and Yellow Jackets. 

Barbiturates are used by swallowing and injecting them as a liquid. They act by slowing down brain function and calming the nerves. They are highly addictive and dangerous to use without a prescription. Barbiturate tolerance is developed quickly, requiring larger doses to provide the same effect. Excessive use of barbiturates can cause a lack of inhibition, impaired memory and judgment, hallucinations, dilated pupils, weak or rapid pulse, coma, and death.


Alcohol use in moderation is socially acceptable in many parts of the world and is not considered a drug by most people. However, alcohol changes the brain like any other narcotic, and addiction can set in quickly if used without caution. Other factors like stress, family history of use, and drinking at an early age can increase one’s risk of developing alcohol addiction. Alcohol increases the brain’s dopamine and serotonin levels, providing the euphoric, relaxed feeling associated with drinking. It depresses the central nervous system, slowing down nerve firing and other functions. 

Continued alcohol use creates potent associations with feelings, places, and people tied to alcohol. These feelings, places, and people become triggers that make you crave alcohol whenever you encounter them. Individuals under the influence of alcohol intoxication are less inhibited and likely to engage in more risky behavior. Alcohol addicts are also likely to have mood swings and impaired decision-making. 


Methamphetamine is a stimulant that speeds up the body and produces a powerful high. It is synthetically produced and comes as a pill or powder which can be snorted, smoked, or injected. Methamphetamine has several street names, including Speed, Shards, Ice, Crystal, Crank, Chalk, and Shabu.

Methamphetamine floods the brain with copious amounts of dopamine, producing a quick and powerful high. As the high passes, the user experiences a crash worse than their normal state. With continued use, the intensity of the high gets weaker, and the user needs higher doses of the drug to get the same high. A cycle develops, and addiction quickly sets in. Methamphetamine use increases heart rate, blood pressure, respiration, and temperature. High doses can lead to strokes, convulsions, coma, and death. 

Crack Cocaine

Crack cocaine is a form of cocaine processed into crystals. It is cheaper than cocaine, and its street names include Crack, Glo, 24-7, Apple jacks, Dice, Sugar Ball, and Kryptonite. Crack cocaine is generally heated and smoked to produce a faster and more potent high than cocaine. The high from crack cocaine is short-lived – usually, about ten to 15 minutes and users will crave higher doses to get the same high as drug tolerance builds.

Crack cocaine produces feelings of invincibility, energy, and excitement that become the opposite when the high wears off. Like its derivative, continued crack use puts users at risk of heart attack, stroke, and death. 


Methadone is a prescription opioid used for the treatment of heroin addiction. It is also used for moderate to severe pain relief and can become addictive if used without medical supervision. Methadone is swallowed as a pill or injected as a liquid and goes by street names like Amidone, Maria, Salva, Fizzies, and Chocolate Chip Cookies. 

When used for the treatment of heroin addiction, methadone should be administered in tapered doses to avoid a secondary addiction to the drug. The effects of methadone addiction and overdose include stomach spasms, shallow breathing, convulsions, weak pulse, coma, and death. 

Crystal Meth

Crystal meth is a more potent form of methamphetamine that is smoked, snorted, or injected. It creates a powerful high and produces a feeling of excitability and euphoria. Crystal meth is highly addictive, and a single use is usually enough to get a person hooked. At higher doses, it can cause violent, aggressive, or psychotic behavior. Continued crystal meth use can lead to strokes, convulsions, coma, and death. 


Amphetamines are a class of stimulant drugs prescribed for Attention Deficit Hyperactivity Disorder (ADHD). These drugs include Adderall, Ritalin, and Concerta. However, they are often used without prescription for appetite suppression, to stay awake, and as a study aid. Street names for Amphetamines include Uppers, Crank, Ice, Bennies, and Black Beauties. 

Amphetamines are swallowed or injected and can become addictive when used for other reasons than prescribed. The effects of abusing amphetamines include dry mouth, constipation, dizziness, and heart conditions. Chronic abuse can lead to psychosis, hallucinations, erratic behavior, coma, and even death.   


Benzodiazepines are a class of prescription depressants that produce sedation, relieve anxiety, and prevent seizures. They include Valium, Xanax, and Restoril. These drugs are addictive when used without supervision and are commonly abused. Their street names include Benzos, Tranks, Downers, and Nerve Pills.

Benzodiazepines are ingested orally or crushed and snorted to produce a calming euphoria. Abuse of these drugs can cause irritability, amnesia, vivid dreams, hostility, clammy skin, and dilated pupils. Sudden withdrawal can cause panic attacks, dry retching, sleep disturbances, coma, and death, so medical supervision is always required when using benzodiazepines. 


Buprenorphine is a prescription pill or injection used to treat opioid withdrawal symptoms. It is also a potent painkiller used for alleviating severe pain from an accident, surgery, or disease. Buprenorphine inhibits the effects of other opioids but also produces a calm euphoria. Users can quickly become dependent without medical supervision.  

The effects of buprenorphine abuse include palpitations, tremors, fever, inability to sleep, loss of concentration, and dizziness. Chronic use of the drug can cause respiratory distress, adrenal insufficiency, and dependence.


Cannabis (also called Marijuana) is a mind-altering psychoactive drug obtained from the cannabis plant. It is one of the most popular drugs in the world, and its use is legal in some places. The drug has many street names, including Mary Jane, Grass, Herb, Ganja, Weed, Pot, Dope, Hash, Smoke, Joint, Skunk, Sinsemilla, and Reefer.

Cannabis may be smoked, mixed with additional drugs, mixed with food (edibles), or brewed as a tea. It is used medically to treat chronic pain, nerve pain, and multiple sclerosis. Cannabis produces a high that leaves the user uninhibited and may cause dependence, especially in people who start using the drug at a young age. Cannabis withdrawal symptoms include restlessness, cravings, confusion, reduced coordination, hallucinations, impaired judgment, paranoia, and respiratory ailments.

Opioid Painkillers

Opioid painkillers are a class of potent analgesics prescribed for controlling pain due to surgery, accident, or disease. They are manufactured from the poppy plant or synthetically and administered as pills or injections. Examples include morphine, oxycodone, fentanyl, and hydrocodone. Opioid painkillers will induce relaxation at low doses, but higher doses can cause potentially fatal respiratory depression. 

Prescription opioids carry a serious risk of abuse and addiction because of the pleasurable feelings they evoke. Effects of abuse include tolerance, increased pain sensitivity, confusion, depression, decreased libido, and constipation. It’s vital to follow a doctor’s instructions when using opioids to avoid abuse, overdose, and death. 


Gabapentin (Neurontin) is a prescription drug for seizures and restless leg syndrome. It is administered orally or injected as a less addictive alternative to opioid painkillers. Gabapentin produces a euphoric calm that can lead to abuse. 

Using gabapentin without a prescription is dangerous and increases the risk of addiction. People already addicted to opioids or similar drugs are the most likely to abuse the drug. Gabapentin abuse can lead to mood swings, increased blood pressure, changes in behavior, sleep changes, and suicidal thoughts. 

How to Get Help for Addiction

Drug addiction doesn’t affect an individual alone; it may impact their family, friends, and others connected to them in several ways. Addiction comes with financial, legal, and social struggles for all involved. If you or a loved one is dealing with drug addiction, the first thing is to educate yourself on the specific addiction to understand the process. You can find relevant information from support groups (Narcotics Anonymous, Alcohol Anonymous), books, and Internet pages on the issue.

You may also need to seek counseling from a professional. Counseling is not for the addict alone but for anyone involved in their support circle. Consider getting specialty help if there are legal or financial issues tied to the addiction. A local mental health facility can provide the counseling you need. The Canadian Center for Addictions helps people understand addiction and the healthier coping strategies available by engaging them in one-on-one counseling with certified counselors, psychiatrists, and mental health professionals. 

Friends and family of addicts should also ensure that they’re not enabling addiction by providing financial support or refusing to make hard decisions when dealing with their addicted loved ones. Many drug addicts will not commit to their recovery until they experience the devastating consequences of drug use. So you should not be in a hurry to pay bills or offer money to an addict – some individuals will not take their treatment seriously till they hit rock bottom. 

It also helps to have realistic expectations when dealing with addictions. Do not get angry or pity yourself or the addict if set goals are unmet. Addiction is complex, and dealing with it is not always a straightforward process. If you are caring for someone dealing with an addiction, ensure the process doesn’t stress you out. Look out for your health and welfare, so you don’t begin to resent or get angry at the addict. Finally, take solace in knowing that addiction is beatable and you can get all the help you need. 


Overcoming addiction is possible, and treatment usually focuses on a multifaceted approach that may include detoxification, therapy, drug rehabilitation programs, individual and peer support, 12-step programs, and aftercare. Addiction affects individuals differently, and what works for one person may not work for the other. Treatment needs for addicts differ and may change depending on the individual’s progress. If you or a loved one is dealing with an addiction, it’s best to seek help immediately so you can begin the journey to a better life. 

Want to find out more about getting help for your addiction or your loved one’s addiction? Get help today by calling 1-855-499-9446 or request a call.

Frequently Asked Questions

What is the number one form of addiction?

Alcohol addiction is the number one form of addiction. Its social acceptance and legal status in many parts of the world make it more abused than any other substance. 

What are the four main drugs?

The four main drugs, based on their effects, are opioids, stimulants, depressants, and hallucinogens. Opioids are derived from the poppy plant and bring on a sense of euphoria and sedation. Stimulants boost the central nervous system, increasing focus and wakefulness. Depressants inhibit nervous system functions and provide a sense of calmness. Hallucinogens affect the brain in a way that alters the user’s perception of the world. They cause the user to experience color, sound, and movement in an altered state of mind.

Is nicotine a drug?

Yes. Nicotine is a stimulant drug that speeds up a person’s attention span and increases reaction time. It is obtained from the tobacco plant and is the primary psychoactive agent in cigarettes, cigars, and vaping devices.

Why do our brains get addicted?

Our brains get addicted because addictive substances flood the brain with dopamine, a chemical that regulates feelings of pleasure. If a person continues to use an addictive substance, the brain adapts and produces less dopamine than usual. Reduced dopamine production makes the brain more sensitive to negative feelings, making the individual crave more of the drug to “normalize” their dopamine level. The need to continue maintaining the brain’s dopamine level makes the user keep taking the addictive substance, and before long, they become addicted. 

What is the most addictive medication in the world?

Opioids are the most addictive medication in the world. They affect the brain’s reward center and carry the highest addiction risk. Examples include morphine, oxycodone, fentanyl, and hydrocodone.

Certified Addiction Counsellor

Seth brings many years of professional experience working the front lines of addiction in both the government and privatized sectors.

Dr. Chintan is a Board Certified Family Physician with an interest in holistic and preventative care as well as healthcare systems. Credentialed Physician with both American & Canadian Board of Family Medicine. Adjunct Professor in the Department of Family Medicine at the Schulich School of Medicine & Dentistry. Telemedicine clinician.

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