Author: Grace Ogren

The most addictive drug varies from person to person. Some genetic mutations make certain drugs more addictive than others. Or, you might find yourself drawn to a seemingly “less addictive” drug, like nicotine, that feels just as powerful as a narcotic. 

With that said, scientists have narrowed down a few of the top addictive drugs. Their addictive potential comes from reactions, communications, and changes in the brain. 

But for each addictive drug, you have resources for recovery. You can speak with your care team to decide which route of treatment works best for you—like going to rehab. 

Heroin

Heroin comes from certain poppy plants. As an opioid, heroin is highly addictive and can change the structure of your brain¹ over time. It usually comes from South America. Dealers often cut heroin with starches, sugars, or sedatives—some of which can have unpredictable and unwanted effects. 

Pure heroin looks like a white powder and tastes bitter. Impure heroin is called “black tar” for its sticky feel and dark color (from impurities). 

You can snort powdered heroin or smoke it. For black tar heroin, you can inject it into your veins or muscles once it’s been dissolved and diluted.

Heroin absorbs into mucous membranes in your nose and lungs—or, if you inject it intravenously, it dissolves directly into your bloodstream. 

Once ingested, heroin bonds to mu-opioid receptors in your brain and activates them², which turns off GABAergic neurons. GABAergic neurons keep dopamine from rushing along your reward circuit. Once the opioid receptor turns GABAergic neurons off, dopamine runs free, which causes a rush of euphoria and a strong sense of general well-being. 

Activating the reward system like this tells your brain opioids are about as great as it gets. Add in the distressing withdrawal symptoms, and getting more can feel like an urgent need. And as you keep taking heroin, you’ll need higher doses to feel the same high as your first time²—which means you’ve built up a tolerance. 

Much of heroin’s danger lies in this rapid high-low pendulum swing.  Soon, you might need high doses to keep from feeling sick. Trying to chase your first high, you might accidentally overdose. 

Taking too much could cause your breathing to slow to null³. You might also feel constipated, nauseous, and extremely itchy. Long-term use can knock your neuronal and hormonal systems off balance⁴—sometimes permanently. 

Alcohol

As a depressant, alcohol suppresses the central nervous system. And, alcohol is both socially accepted and easy to get—a tricky combination. Alcohol causes a sense of happiness and well-being⁵, which activates your brain’s reward system. It sees alcohol as medicine and, eventually, as something you inherently need to survive. 

Because of its addictive nature and easy access, alcohol is one of the most dangerous substances to abuse⁶. Over half the visits to emergency rooms have something to do with alcohol. It’s also one of the 2 most-used substances, the other being nicotine. 

Different alcoholic drinks have different levels, or percentages, of alcohol. For example, an alcoholic seltzer drink is usually 5-8% alcohol; in something like vodka, the rate goes up to 40%. 

As with illicit drugs, you can build a tolerance to alcohol. So, you might need to add a splash of vodka to your seltzer or have an extra glass of wine to feel how you’re used to feeling on alcohol. The longer this continues, the more you’ll need to drink. 

Withdrawals include insomnia, anxiety, tremors, and seizures. For many, safely detoxing from alcohol requires medical supervision. 

Nicotine

Nicotine, like many other drugs, causes a release of dopamine⁷. But with nicotine, the rush isn’t quite as intense as something like heroin. Nicotine has such addictive power because of its repetitive nature⁷ and because you can use it with other activities (and substances). 

Smoking a cigarette or vaping can enhance the pleasure of other activities⁷, like watching a movie, partying, having a cup of coffee, or listening to music. Even though nicotine only adds to these activities, your brain still associates it as the source of joy in those situations. And so, you learn to keep smoking, subconsciously chasing satisfaction.

What used to be fun and motivating might seem boring or too mundane without the added boost from nicotine, so stopping can be challenging⁷. You might even feel like nothing’s enjoyable without smoking. That’s because nicotine represses your natural dopamine-release functions, and once they’ve been suppressed for so long, it can take time for your brain to adjust and provide its own. 

Though unpleasant, nicotine withdrawals won’t hurt you⁸. You may have a bad headache and experience cravings. You might also feel more anxious and hungry. But all withdrawal symptoms pass with time. 

Benzodiazepines

Benzodiazepines, or benzos, subdue the central nervous system. They’re usually prescribed to help with anxiety, panic disorders, and insomnia⁹ for their calming, sedative effects. But benzos can also be highly addictive.

Some benzodiazepines can cause dependence faster than others. But usually, people use them with another drug⁹ to balance or complement other effects. Alcohol and benzos, for example, produce an enhanced calm but can dangerously suppress the central nervous system.

The benzodiazepine Rohypnol, AKA roofies, acts as a powerful sedative. Some misuse benzos like Rohypnol against others. But usually, benzodiazepines appeal for their countering effects against opioids and for self-sedation.

Benzodiazepine withdrawals⁹ can feel extremely uncomfortable. You could experience nightmares, anxiety, insomnia, psychosis, hyperpyrexia (extremely high fever), and convulsions. For those reasons, detoxing under medical supervision is a safer option. 

Methamphetamines

Doctors may prescribe the psychostimulant methamphetamine, or metamfetamine, to treat attention deficit hyperactivity disorder (ADHD)¹⁰. In healthy doses (for those who need it), methamphetamine’s effects resemble the brain’s fight-or-flight response¹⁰. This response  increases energy, alertness, and focus. But it’s also a drug of abuse with a high potential for addiction.

Methamphetamine looks like a white powder¹¹ or crystal-like rocks. It’s relatively easy to make and cheap to buy. Many pseudo-scientists make methamphetamine in discreet labs, usually hidden off the beaten path.  But most meth comes from larger labs in Mexico and overseas countries. 

Methamphetamine releases dopamine, serotonin, and norepinephrine¹⁰, which contribute to pleasure, satisfaction, and alertness. Using methamphetamine for pleasure can cause binges, since the desired effects only last a few minutes. And because meth is one of the cheaper stimulants and easy to get, feeding the binges might not seem like a problem. 

But, as with other drugs, your brain changes with repeated doses. You might build up a tolerance¹², prompting higher doses. Your brain may also stop producing dopamine and serotonin on its own. 

Methamphetamine withdrawals¹² can cause cravings, depression, anxiety, violent behavior, confusion, insomnia, hallucinations, delusions, and psychosis. 

Cocaine

Cocaine is another highly addictive stimulant¹³. It’s also one of the most common illicit drugs¹⁴ in America. 

Cocaine prevents the reuptake of dopamine¹⁴, meaning dopamine stacks up on dopamine receptors. This sends an intense rush of pleasure and stimulates the entire reward pathway¹⁵, causing your brain to see cocaine use as intrinsically rewarding. Even the sights, sounds, and places associated with cocaine use can trigger the need for a dose. 

As with many other drugs, you can become used to the effects of cocaine, or “tolerant”. You’ll need more and more to feel the same high as your first time. This puts you at risk for an overdose. New dangers also lie in adding vermisol to cocaine¹⁵, which is used as a cutting agent. Sometimes, fentanyl even makes its way in. 

The withdrawals from cocaine¹⁶ include insomnia, tremors, cravings, and hyperactivity. 

Crack Cocaine

Crack cocaine is a smokeable version of regular cocaine¹⁷. So it’s also a stimulant, and addictive, but even more potent due to how it’s ingested. Before it’s smoked, crack cocaine looks like small rocks or crystals. 

The membranes in your lungs absorb crack cocaine¹⁸ easily and quickly, resulting in an almost immediate high. The high goes away faster than powder or liquid cocaine, which could prompt a binge—smoking until you run out of crack or money.  

The reinforcing action is even more powerful in crack cocaine¹⁷. Your brain thinks it’s a good idea to keep having more more often, trying to realize the pleasure it knows crack can give.

Barbiturates

Similar to benzodiazepines, barbiturates are a depressant¹⁹ generally used for anxiety, headaches, seizure prevention, and insomnia. Those who misuse this prescribed medication usually do to counter the effects of other drugs—typically stimulants like cocaine.

You can take barbiturates as a pill or liquid. Barbiturates make you feel sleepy, relaxed, and at ease¹⁹. They can also impair your memory and judgment, and make you irritable. You might also feel paranoid and suicidal.  

Overdosing on barbiturates¹⁹ causes your heart rate to rise, your breathing to slow, and your body temperature to lower. Overdoses can also cause comas and death.  

Methadone

Doctors prescribe methadone, a synthetic opioid²⁰, to treat opioid use disorders (OUDs). It relieves cravings, reduces withdrawal symptoms, and doesn’t provide the same “rush” of euphoria as other opioids. At the correct dosage, these factors make methadone a valuable treatment element²⁰ for OUDs. 

Part of what makes methadone maintenance treatment (MMT) effective is the low risk for addiction. And, in MMT, you don’t have to share needles or risk taking heroin, cocaine, etc., of unknown purity²⁰. Doctor oversight adds another element of safety. 

But methadone does have an addictive element. The usual dose for OUD management ranges from 60+mgs²⁰. Sometimes, patients in treatment buy extra doses from others or hoard doses to eventually get a euphoric effect from methadone. 

Taking too much methadone can cause dangerous effects, especially if you’re on other medications. Signs and symptoms of an overdose²⁰ include dizziness, slurred speech, unconsciousness, slow pulse, shallow breathing, tiny pupils, and frothing at the mouth. 

Naloxone reverses the overdose effects of methadone²⁰, as it does with other opioids. 

Marijuana

Marijuana, or weed, comes from the marijuana plant. Its addictive psychoactive properties lie in the THC²¹ (delta-9-tetrahydrocannabinol) in marijuana. You can ingest marijuana in many ways²¹—smoking the leaves, drinking it in tea, eating foods with weed, and smoking concentrated weed in the form of a sticky resin.

Weed produces a sense of relaxation²² and a milder feeling of euphoria. Weed can also make you pretty hungry (or, give you the munchies) and laugh easily. You’ll experience these effects right away if you smoke weed. 

Eating it slows the onset by a half hour or more, which could prompt you to redose, thinking it’s not working. Taking too much can cause anxiety, fear, paranoia, and panic²²—the opposite of what weed usually feels like. Extremely high doses can even cause acute psychosis.  

Marijuana activates the reward system²³ in your brain, causing a flood of dopamine to course along your reward pathway. After continued use, your brain teaches you to keep having weed as a way to feel reward and satisfaction. Continued usage can also impair your memory, learning abilities, and balance²³.

Starting weed at a young age leads to a higher risk of addiction²⁴. But anyone at any age can find themselves addicted, meaning they’d feel withdrawal symptoms and be completely unable to stop—even when they know they should. In states that don’t monitor distribution, the potency of THC continues to rise too. This creates consequences scientists and health professionals haven’t fully realized yet. 

But for each substance and its potential for addiction, you have opportunities to recover. 

Find Effective Drug Addiction Treatment Near You

The most addictive drug could vary widely from person to person. While you can’t stop smoking cigarettes, someone else might not feel able to stop drinking—but drinking isn’t a problem for you. 

Fortunately, treatment for drug addiction caters to this variance. You can get the care you need at a residential rehab, outpatient facility, or detox unit. Your care team can help you decide which type and level of care will best meet your needs. 
To see a comprehensive collection of rehab facilities, you can browse our list of drug addiction rehabs to see photos, prices, reviews, insurance information, and more.