What Are the Most Addictive Drugs?


As a rehabilitation clinic we are often asked by families “what are the most addictive drugs?”. The answer to this is complex, as drug profiles are so different and the development of addiction in individuals is multifaceted.

The quest to determine the addiction risk of drugs is one that is still ongoing. This exploration delves into the addictive potential of opioids, alcohol, cocaine, and other commonly abused substances, shedding light on their effects and the path to recovery.

What Is the Most Addictive Drug?

All drugs have the potential to create psychological or physical addictions, whether they are legal or illegal. Even the question of what drug is most addictive is a complex one to answer, as it depends on many variables.

Some drugs have the potential to be perceived ‘more addictive’ either because they affect the brain in multiple ways (like alcohol) or because they have such an intense effect (like cocaine). There are also other drugs that may not create a physical dependency but can create a strong psychological addiction, like LSD.

There is also anecdotal evidence from ex-addicts in terms of what drugs are most difficult to detox from, or to abstain from. A common expression, for example, is that “nicotine is more difficult to quit than heroin”. Whether that is clinically factual or not is debatable, but the anecdotal evidence would suggest that it’s true.

The development of addiction is also multifaceted. And does not only depend on the ‘strength’ or ‘addictiveness’ of the drug. Two people may both start smoking cigarettes socially and one of them gets addicted where the other does not. Some of the factors to consider that may influence if someone develops and addiction or not include:

  • Genetics: Research consistently demonstrates that a family history of addiction or problematic substance use corresponds with a higher risk of someone developing an addiction in their own life. This may be due to genetically inherited traits that affect how an individual’s body may respond to substances
  • Biological Factors: Brain chemistry and structure can massively influence how vulnerable someone is to addiction. This includes potential past brain traumas or injuries, as well as neurotransmitter function
  • Mental Health: Those who experience a mental health illness are much more vulnerable to developing addiction. These people may, for example, use substances to self-medicate or to cope with past traumas or emotional distress
  • Environmental Factors: The environment where someone lives, or even grew up in, can massively influence how likely they are to develop an addiction. This can be because of cultural acceptance of substance use, peer pressure, family normalcy, exposure to stress, and more
  • Trauma and Stress: Those who have experienced trauma, either in the past or present are more likely to develop addictions. Those who experience any form of chronic stress also have an increased likelihood.

When combining all factors of consideration however, there are three drugs that stand above the rest in terms of potential for addiction:


Opioids, also known as narcotics, include both illicit drugs such as heroin and opium, as well as legal drugs such as fentanyl, codeine and oxycodone. While most people will be familiar with the opioid addiction epidemic occurring currently in the United States of America, there is currently a boom in opioid addiction worldwide.

These drugs work by binding to the opioid receptors in the brain which repress the central nervous system. This means that they slow down messages between the brain and the body, leading to feelings of relaxation, drowsiness, euphoria, and tranquillity, among other effects.

This process also promotes the release of endorphins and other feel good neurotransmitters in the brain. This dual process acts powerfully on the reward systems in the brain and creates a strong physical and psychological dependence.

In addition to the effects on the brain, the powerful effects of relaxation and euphoria can be deeply psychologically addictive. This is particularly true of those people who are in psychological or emotional distress, either due to a mental illness, past trauma, or chronic stress.


Although legal in most parts of the world, alcohol is consistently proven to be the drug that causes the most harm globally, both to individuals, communities, and wider society. Many people do not consider alcohol to be very addictive, due to the fact that it is so widely consumed. However the sheer number of people who consume it means that the number of those who have developed an addiction can be much higher than those of other drugs as well.

Alcohol works by enhancing the effects of GABA (gamma-aminobutyric acid) which is an inhibitory neurotransmitter, creating the sedative effects of alcohol as explained above. It also suppresses glutamate, which is an excitatory neurotransmitter, also contributing to the sedative effects.

As it serves a dual function, this contributes to it being highly physically and psychologically addictive. This is also particularly true as many people tend to self-medicate with alcohol, either on a mild basis (a drink or two helps me be more chatty) or on a more severe basis (if I don’t stop drinking, these bad memories will go away).

Alcohol is also one of the most dangerous drugs to detox from. While many drugs do not carry a risk of detox fatality, this is not the case for alcohol and opiates.


Cocaine, extracted from a plant leaf base, is commonly found in three forms. The most common form is a fine white powder, freebase (a more pure version of the regular cocaine powder) and crack cocaine, in the form of small crystals.

Cocaine is a stimulant drug and works by speeding up messages between the brain and the body, as well as engaging the reward system of the brain by encouraging the release of ‘feel good’ neurotransmitters such as dopamine and serotonin.

How addictive cocaine is depends on several factors including its purity, what form it is in, and the way in which it is taken. Cocaine is most often snorted in its powder form and smoked in its crystal form. However, the most dangerous and addictive way of taking cocaine is via intravenous injection.

The biggest risk with intravenous injection of cocaine, opiates, or any other drugs is blood-borne viruses such as HIV and hepatitis. However long term intravenous use can also lead to collapsed veins, infections, and ultimately loss of limbs of sepsis.

What Are the Other Most Addictive Drugs?

As mentioned above, all drugs have the potential to become habit forming. However, there are some drugs that treatment centres see more often than others.


Whether by cigarettes, chewing tobacco, or vapes, nicotine is commonly referred to as one of the most addictive drugs accepted in society. This is not only because of the way it affects the brain, but also because of how common it is.

Most people who start consuming nicotine often cite peer influence as a key reason. Either because they saw someone they admired doing it and wanted to emulate them, or because their peer group started consuming and they felt pressure to join in.

Once someone does start consuming nicotine, the stimulant effect acts on the brain’s reward system and creates a pleasurable effect of focus, relaxation, and mild stimulation. These contribute to the psychological dependency while also creating a physical addiction.


Another stimulant, amphetamines are also considered to be highly addictive. The rate that dependency is developed depends largely on whether the amphetamine is swallowed, snorted, smoked, or injected.

Amphetamines work to speed up the processes in the brain and create a massive spike in dopamine and serotonin levels. This not only acts as a dangerous reward system for the brain, but the euphoric effects risk creating a psychological addiction to the sensation as well.

Many people are familiar with the illegal forms of amphetamines such as methamphetamine, or crystal meth. However there are also several legal forms of amphetamine used as medications, such as those used to treat ADHD and narcolepsy. Amphetamines can be addictive in any form, whether they are prescribed or not.


These medications are often prescribed for anxiety and sleep. While their potential for addiction is widely established, medical practitioners without addiction experience often over-prescribe them, leading to an international epidemic of benzodiazepine addiction.

‘Benzos’ work by enhancing the effects of a neurotransmitter called GABA which acts like a break pedal in the brain, slowing it down and creating feels of relaxation and sedation. These sensations alone could cause a psychological addiction.

In addition to this, physical dependence is also quickly established, leading to nasty withdrawal symptoms should the individual stop taking them. They then often take more to avoid those symptoms, leading to a vicious addictive cycle.


Due to its rising popularity as a ‘medicinal’ and recreational drug, there is a common perception that marijuana, THC, or CBD consumption is harmless, even health-promoting. However the risks associated with marijuana consumption and addiction can be very impactful.

Marijuana does not typically create a physical dependency in the same way that many of the other drugs do. In this way, someone could smoke weed all day every day and then not experience any physical symptoms of withdrawal if they were to stop cold-turkey.

Despite this, there is a strong risk of a psychological addiction developing due to the sensations of relaxation, humour, and good mood that marijuana often elicits. People can crave this feeling and will often sacrifice other experiences in life in order to experience it.

Beyond this, marijuana addiction can be difficult to treat as the consequences of such an addiction are often not considered very grave or dangerous like alcohol or heroin addiction. Often the damages are viewed as ‘lost potential’ or ‘lost opportunities’, and prospecting on how things ‘could have been’ or ‘would have been’ is difficult to impress upon someone with an addiction.


Probably the most widely consumed drug across the world today, caffeine can come in the form of beverages, powders, tablets, and shots. Many people will consume caffeine daily without a second thought as to the risk for addiction.

The reality is that most people will not experience a severe addiction to caffeine, as its effects are largely mild when consumed in moderate amounts. The problem occurs more when people consume caffeine in extreme amounts, such as energy drinks or sports supplements.

Caffeine is a stimulant, like nicotine and amphetamines, and works in much the same way. The reward system activated in the brain combined with the pleasant effects of focus, energy, and boosted mood can be difficult to combat.

We all know someone who ‘cannot start my day without a coffee’. Mild psychological dependency may not cause problems in life, but if you are concerned about your use you can always consult with a professional to access help.

What Can I Do if I’m Addicted to One of These Drugs?

If you think that you, or someone you care about, are addicted to one of these drugs, the first step is to reach out to a medical or therapeutic professional with experience in addictions. It is never too early or too late to ask for help and support.

It is important to ask for a medical opinion and full assessment prior to any attempts to cut down or detox from substances, as the withdrawal process for some drugs can be potentially deadly. This support is best asked for from a professional who has experience in addictions, and not necessarily your primary care doctor.

Many out-patient clinics and services will offer to complete assessments and support at-home detoxes. However, the safest, and most efficient way to address addiction is within an in-patient rehabilitation facility, such as Clinic Les Alpes.

It is important to also remember that addiction does not simply stop once the detox is over. In order to fully recover and protect yourself from addiction in the future, it will be key to access long-term psychological counselling and therapy. This will not only address the root causes of why your addiction may have developed, but will also help you to establish strong coping and protective strategies.

Summary – What Are The Most Addictive Drugs?

Navigating the landscape of addiction reveals a complex web of biological, psychological, and environmental factors. The key to untangling this web lies in seeking professional help, for yourself and others, as soon as possible where drugs are concerned.

Acknowledging the complexity of different drugs and of addiction itself can help us to better understand that asking what are the most addictive drugs is less of an answer than we may have thought it could be.

Clinically Reviewed By

Brittany Hunt

Brittany Hunt is an internationally experienced clinician, specialised in treating addictions and co-occurring disorders. Having worked in the public and private sector, she utilises holistic and evidence-based approaches designed to empower the patients in their recovery journeys. A graduate of The University of Auckland, she has a Bachelor of Health Sciences majoring in Mental Health and Addictions, a diploma in Psychology and Counselling and a Post-Graduate degree in Health Sciences, majoring in Addictions. She is a fully registered practitioner under the Drug and Alcohol Association of Aotearoa New Zealand (DAPAANZ).

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