Addiction blights the lives of millions of Americans.

It might be a surprise the most addictive substances in the world are the most popular. A progressive, chronic and relapsing disease, addiction can be assumed when substance abuse becomes utterly compulsive. The addict will continue to use the substance in question despite often ruinous consequences habitually.

The National Institute on Drug Abuse assesses the cost to the nation of tobacco, drugs, and alcohol abuse at $740 billion annually. Tens of millions of Americans suffer from some form of dependency or other.

The consequences of chronic and untreated addiction are similar regardless of the substance. What makes this even worse is that addiction, however widespread, is still often stigmatized. Indeed, the very word addict has negative connotations outside of recovery circles.

Nevertheless, addiction can be treated, and it’s perfectly possible to leave dependency on any given substance behind and to start a new path of sobriety, with the exception of those born dependent on drugs – think crack babies of the 80s and 90s – it’s more a case of rediscovering an old path, a path without the crutch of drink or drugs.

For a fuller look at addiction, check out our detailed resource right here.

Today, we’ll look briefly at some of the most addictive substances in the world, some legal and some illegal.

Opinion varies even among scientists and researchers to the extent it’s not practical to compile a strictly numbered list with any real validity.

Also, the way in which substances affect individuals varies, too.

To a smoker sucking down two packs of unfiltered cigarettes a day even after the point they actively dislike smoking and tell anyone who cares to listen they’d love to quit, there’s no drug more potent than nicotine.

A desperate crack addict chained to the pipe would tell you nothing is more addictive than crack cocaine.

For heroin users unable to put down the needle, no substance on earth has a more powerful draw.

So for these reasons, we’ve avoided numbering this list and alphabetized it instead so as not to put any unjust weighting on any particular substance. All we will say is that anything on this list of the most addictive substances in the world should be treated with extreme caution.

Before we launch in, there are some basic criteria established as salient when considering how addictive a drug is.

Relevant Factors For Assessing How Harmful a Drug

A group of chemists, psychiatrists, and pharmacologists at the Royal College of Psychiatrists ranked dangerous drugs according to the following three factors:

  • Physical Harm
  • Social Harm
  • Dependency

The results of their attempt to develop a scale by which to measure the potential harm of drugs when abused were published in The Lancet, a benchmark medical journal.

While the first two categories don’t strictly deal with addiction, dependency centers firmly on the issue, the harmfulness of the drug is also worth taking into account since if a drug were addictive but had absolutely no adverse effects, it wouldn’t generally be considered problematic.

Physical Harm

Any of the drugs on our list today are capable of causing health problems, injury and associated physical issues both in the short-term and over a more extended period.

Social Harm

The social harm of a drug can be classified according to the direct results of intoxication in terms of assaults, DUIs, and other offenses that harm others not just the addict.

Healthcare costs are also a classic indicator of the harmfulness of a drug.

The way in which some drugs have a disastrous influence on family life is another way in which we can judge how harmful or otherwise a substance might be.


The researchers cleaved dependency into three sub-categories:

  • Pleasure: The euphoria a user feels when taking a drug. Intensely pleasurable drugs can lead to rapid psychological dependence and subsequent addiction.
  • Physical Dependence: If the withdrawal of a drug causes a range of physical side-effects from headaches and nausea through to anxiety and even seizures, the substance is addictive.
  • Psychological Dependence: Acute cravings when a drug is withdrawn are another critical metric of addictiveness.

Most Addictive Drugs

To reiterate, we are not listing these drugs in any particular order.

We’ll give you a capsule overview of why and how some of these substances lead to the onset of addiction, and we’ll assume some knowledge rather than breaking down every element of every drug.

In the coming weeks we’ll be doubling down in much more detail on some of these substances individually, but for now, here’s a glimpse at a dishonorable roll-call of the world’s most addictive substances.


With over 2 million worldwide members of Alcoholics Anonymous, 1.3 million of those US citizens, alcohol might be legal, but it’s remarkably addictive in the wrong hands.

For the vast majority of people, it’s entirely possible to enjoy a few beers at the weekend, a glass of wine with dinner, and even to get drunk from time to time with no signs of dependency or addiction.

For alcoholics, it’s a different story entirely. It’s estimated that fully 1 in 8 Americans suffers from alcohol use disorder (AUD). That’s quite a number.

Depressing the central nervous system, alcohol also relaxes and loosens you up. Inhibitions drop along with anxiety. When you consume alcohol, your brain releases dopamine and endorphins linked to reward processing, so you feel good while pain is also to some extent eliminated.

Over time, tolerance builds and, once addicted, harmful physical and psychological issues manifest. Severe health problems like cirrhosis of the liver, outright liver failure, and heart disease are relatively commonplace. Problems spill over socially with alcohol-induced traffic fatalities, violence and relationships unraveling. Alcohol can also lead to clinical depression.

With almost one-quarter of people who drink developing alcohol dependence at some point, there’s little argument this is one of the most addictive substances in the world. While legal, it’s wildly unlikely alcohol could be brought successfully to market if introduced today.

Attempting to stress the importance, people can die from how harsh widthrawl symptoms are from alcohol. It’s important to find an alcohol treatment center to help detox from drugs and alcohol.


Benzodiazepines are a group of prescription drugs commonly and legally prescribed to treat alcohol withdrawal symptoms, insomnia, anxiety and a range of other conditions.

Perhaps the most well-known examples are Xanax and Valium.

There’s no argument that these drugs are highly effective at accomplishing their various goals. If you need to sleep, one of these pills will do the trick. If you’re feeling particularly anxious, they’ll calm you down. This efficacy leads to the desire for more, though.

Tolerance rapidly builds due to a short half-life, and it’s remarkably easy to become addicted in as little as six weeks according to the NIDA (National Institute on Drug Abuse).

An unfortunate occurrence with benzodiazepines is that once addicted; you can experience rebound symptoms of the very disorder for which you sought treatment. You become more anxious rather than less, for example, leading to the perverse desire for more pills.

Immortalized in the Rolling Stones song Mothers Little Helper, benzodiazepines are just as much of a problem today as they were back in the 60s when prescriptions were doled out as liberally as the values of that freewheeling decade.

Unlike most substances on this list, the only defense is that they have bona fide medical uses when used as part of controlled, supervised detox or used sensibly to treat short-term problems like a spell of insomnia.


Cocaine needs no introduction even to someone with absolutely no first-hand knowledge of drugs.

A stimulant derived from coca plants, the method of delivery and truncated half-life means you can become addicted very quickly. Quitting can be extremely tough.

Cocaine has a direct effect on the way your brain uses dopamine to ping messages from neuron to neuron. Under the influence of the drug, your mind will be unable to turn off the receptors while a steady stream of dopamine remains.

Tolerance builds swiftly. Once withdrawal sets in, the brain cries out for the dopamine it’s no longer getting causing you to seek out more of the drug. Reward pathways in the brain start malfunctioning.

Side effects include increased blood pressure and heart rate, nosebleeds, and damage to the septum in cases of abuse – cocaine is usually snorted through furled bills or a straw. In severe cases, cocaine abuse can lead to more serious health problems like Parkinson’s disease and bowel decay.

Cocaine is an incredibly addictive drug with damaging effects that will always crop up on any list such as this with just cause.


As Dennis Leary once famously said, “Only in America would a guy invent crack? Only in America would there be a guy that cocaine wasn’t good enough for.”

Less glibly, crack is an impure but more potent mixture of cocaine and baking powder commonly referred to as freebase. Crack is smoked rather than snorted, usually through a glass pipe. This allows the drug to seep directly into the lung tissue bringing about a different effect.

The high is both more intense and more rapid than that from powdered cocaine and can last as little as 15 minutes.

This short-lasting high married to crippling withdrawal symptoms means crack is exceedingly addictive with tolerance quick to build and cessation leading to numbing depression, insomnia, and great agitation.

Traumatizing to body and mind and responsible for the destruction of the social landscape in many poor urban areas, the crack epidemic of the 80s might be history, but this addictive substance is still very much alive and kicking.

Crystal Meth

In many ways, methamphetamine, often known as crystal meth, is similar to cocaine…

It acts on the central nervous system increasing levels of dopamine but with the added kicker of also releasing more norepinephrine.

Boosting energy, mood, and sexual desire, meth has a high addiction liability with post-acute withdrawal symptoms that can drag on for months.

This drug conditions your brain to require more to achieve the same effects.

Once addiction to meth takes hold, consequences span from psychosis and hallucinations to memory loss and painful bouts of depression. Weight loss through malnutrition and dental decay are standard. In some cases, meth addicts end up committing suicide.

An inbuilt disadvantage is that drugs like meth are often cut with other toxic agents leading to further complications.


As prescription opioids continue to be abused in growing number – more on those in due course – the use of heroin in the US has also been steadily rising. There’s a body of opinion suggesting that opioids act as a gateway drug to heroin itself.

Heroin, an opiate derived from the opium poppy, jacks up the level of dopamine in your brain enormously. Users experience euphoria and a general feeling of numbness. Pink Floyd’s Comfortably Numb is one of many songs dedicated to heroin addiction, and the title is particularly descriptive of the way a heroin addict feels. As the dopamine receptors within the nucleus accumbens area in the center of the brain are repeatedly bombarded, the nerve cells end up exhausted from chronic overstimulation.

The drug can be snorted, smoked, or injected. A user might experiment by smoking or snorting, but once addiction takes hold, inserting becomes the standard method of delivery for reasons of economy and potency. Roughly 25% of people who try heroin go on to develop an addiction.

Dangerous in pure form, street heroin is usually anything but pure. Cutting agents are impure and often toxic exacerbating already negative effects.

An overdose is only five times the dose required to generate a high, so aside from a battery of grave health issues heroin addiction brings about, the possibility of OD-ing is significant.

Physically, psychologically, and socially ravaging, heroin is a savagely addictive substance by any standards at all.


The primary addictive ingredient in cigarettes, any smoker is acutely aware that smoking is both physically and psychologically addictive.

Over two-thirds of Americans who tried smoking went on to develop an addiction. This is more almost triple the figure of those who dabble with heroin and makes for truly sobering reading.

With over 1 billion smokers worldwide and millions killed each year from tobacco-related issues, smoking is the principal cause of preventable disease and death in the US.

The rapid delivery of nicotine and absorption into the lungs and brain mimics an acetylcholine receptor while also diminishing the number of receptors produced. Over time, the brain undergoes changes and addiction through nicotine exposure ensues.

As well as 16 million Americans suffering from serious illnesses brought on by smoking, the dangers of secondary smoking make nicotine particularly insidious.

Still, despite worldwide attempts to ban smoking in public places and to continue educating the public, 1 billion people across the globe are still seemingly unable to quit.

Opioid Painkillers

Addiction to painkillers continues to spread across all areas of American society.

Opioids like Oxycodone, Vicodin, and codeine exert a particularly vicious grip. Physically and emotionally addictive, tolerance to these painkillers is also quick to develop. You can become dependent on opioids in a matter of days rather than weeks or months.

The standard route to addiction is via a legitimate prescription. The user has no idea of their addiction until they stop taking the painkillers. At this point, painful withdrawal symptoms kick in leading the user to make more rather than face up to the discomfort.

Recreational use is also routine and naturally leads to the same result of pretty rapid addiction.

The health effects of opioid abuse should not be underestimated. These painkillers can wreak havoc on all major organs within the brain damage, liver damage, and respiratory failure the most extreme outcomes. Prescription painkillers might seem benign on the surface, but they’re one of the most deadly and addictive substances when tolerance and dependency build.


If you’re concerned about any element of addiction, don’t hesitate to reach out.

Now we’re up and running; we’ve got a dedicated team in place to ensure this blog is a go-to resource for anyone with any concerns about substance abuse. We’ve got plenty more on the slate for this coming month as we delve deeper into the science of addiction, and we’ll also be looking at how to spot addiction developing in a family member.