There is no straightforward answer to the question of which drug is most addictive. The subject of addiction in general does not come in black-and-white terms. There’s a lot of gray area when it comes to figuring out if a person has an addiction disorder, and the very definition of the word addiction leaves a lot of room for interpretation.
Most addiction experts agree that there’s both a physical and a psychological aspect to addiction. Addictive substances have physical effects on the brain and cause pleasurable sensations that prime the brain’s pleasure-reward response. At the same time, a person’s stress levels, life satisfaction, attitudes about drug use, and the presence of other mental illnesses are all considered to be factors in the development of an addiction disorder. People can even become addicted to substances that are not considered to be physically addictive because they can form an emotional attachment to the drug and any kind of intoxicant will cause the brain to associate that drug with a pleasure reward.
There is therefore no definitive way to measure how addictive a drug is. However, experts and researchers have found way to rank common drugs for addictiveness based on five factors:
- Dependence: This is based on factors such as the relapse rate, the percentage of people who become addicted to the drug versus how many simply use it, self-reports of the need for the drug from addicted persons, how hard it is to quit, and the degree to which the drug is likely to be used despite knowledge of the drug’s harmfulness.
- Withdrawal: The severity of the symptoms that arise when addicted persons stop taking the drug.
- Tolerance: How soon users find that they need to take more of the drug to get the same effect and how much more they need to take.
- Reinforcement: This is based on human and animal experiments testing regarding how likely subjects are to seek out more of the drug given.
- Intoxication: This is how high people typically get on the drug.
Based on these criteria, we can begin to discuss how addictive some of the most popular legal and illicit drugs are in comparison with one another.
Alcohol is one of the most addictive drugs
If you look purely at the number of people addicted to alcohol, you might come to the conclusion that this is the most addictive substance. According to the National Council on Alcoholism and Drug Dependence, 17.6 million people in the US suffer from an alcohol use disorder. However, it should also be taken into account how many people use alcohol in general due to its legal status and fairly high social acceptability. It can also be very difficult to quit, but ease of access and alcohol marketing campaigns play a significant role in that. Alcohol might be considered moderately addictive based on this category.
Alcohol is considered to be one of the very worst in terms of withdrawal. In severe cases, alcohol withdrawal can even be deadly, producing a condition called delirium tremens that can quickly progress to irregular heartbeat and seizures that are sometimes fatal.
People tend to build up a tolerance to alcohol at a moderate rate. Even people who only drink casually may find they need a little more than when they first started in order to get drunk, though this can be difficult to measure due to the fact that alcohol intoxication can be affected by many outside factors, including what the person ate that day.
Alcohol is also not as high as others on the reinforcement scale due to the fact that, though alcohol intoxication can be very pleasant, it doesn’t produce any kind of intense euphoric high associated with drugs like heroin and cocaine. However, because it is physically addictive, it has a higher reinforcement score than drugs like cannabis.
People can become very intoxicated on alcohol before they reach the level of overdose. The physical and psychological effects of alcohol intoxication are rather severe and varied. It’s always clear when someone’s had too much to drink. Adding to this problem is the fact that alcohol lowers inhibitions, which can contribute to the alcohol binges that increase the risk of addiction.
Nicotine is one of the most addictive drugs
In terms of dependence alone, nicotine is often considered to be the most addictive of the well-known and commonly studied drugs, outpacing heroin and cocaine. This often comes as a surprise to people due to the fact that it doesn’t cause the same problems associated with alcohol, cocaine, or heroin. However, a high number of people who start smoking tobacco become addicted, and people report severe difficulties when trying to quit despite the alarming health risks. There are still over 480,000 deaths every year from cigarette smoking, according to the Centers for Disease Control and Prevention.
Nicotine withdrawal, while troublesome, is actually considered to be more moderate compared to heroin and alcohol withdrawal. Cravings and emotional symptoms like irritability tend to be the most prominent, but it doesn’t keep people in bed with pain and flu-like symptoms for a week.
Tolerance to nicotine builds rather quickly. It helps that due to the high dependence level, nicotine users tend to end up taking the drug multiple times per day fairly soon after first trying it. High frequency of use is associated with a faster buildup of tolerance and a higher risk of addiction.
Nicotine is associated with a lower reinforcement level, as it doesn’t produce the same kind of pleasurable sensations as other drugs, especially in new users. This means that fewer people who try nicotine for the first time will become addicted, as more of these individuals don’t bother to go back a second time. However, this only makes the high dependence level of nicotine all the more alarming.
Nicotine intoxication is generally quite mild, associated with only low-level stimulant effects. This contributes to the fact that fewer people (and test animals) go back for more.
Heroin is one of the most addictive drugs
Heroin is considered to have a high dependence rate – about 23 percent of people who use it will develop an addiction to it. Relapse is an especially severe issue when it comes to this drug, and many people die from overdose after going back to the drug or simply trying to achieve the effects of that first euphoric high. That high and the fear of withdrawal also contribute to users’ reluctance to quit, and heroin cravings are often considered some of the most intense of any drug.
Though not directly dangerous, withdrawal from any opioid is reported to be a terrible experience responsible for many relapses. Addicted individuals describe terrible pains, intense malaise (a general feeling of disturbance), and flu symptoms that could be like the worst flu they’ve ever had. Few are able to make it through these symptoms without professional assistance, which is why medications to treat heroin addiction, such as methadone, are often used to help addicted individuals. Without these medications or any professional help, success rates for quitting any opioid are at a mere 5-10 percent.
Users build up a tolerance to heroin very quickly. In fact, people often report that they are never able to experience the intensity of their first heroin high once it’s over, causing them to “chase” that feeling, sometimes for years. This is also part of what makes heroin so dangerous. Addicted persons often end up mixing heroin with other drugs in order to achieve a better high after developing a tolerance, increasing the risk of overdose.
Due to the intense euphoria experienced from heroin, reinforcement levels are also high. Test animals frequently return for more doses of this drug once its effects wear off. Heroin is often associated with drug bingeing behavior in which people continue to take the drug immediately after effects start to diminish, dramatically increasing addiction potential.
Heroin’s intoxication levels are typically only beat by alcohol’s levels. Heroin users experience a significantly sedated state after the euphoria, often repeatedly nodding off, even in the middle of conversation.
Cocaine is one of the most addictive drugs
Although the typical view of cocaine is that it’s very addictive, its dependence level is not as high as either nicotine or heroin. Even though people do experience a euphoric rush from this drug, fewer will actually develop an addiction. Relapse rates are also significantly lower due to an easier withdrawal and less intense cravings. However, these rates tend to be higher for the cheaper cocaine derivative known as crack cocaine.
Intensity of withdrawal symptoms for cocaine is considered to be the lowest out of all four drugs discussed here. In fact, there are often no observable physical symptoms associated with cocaine withdrawal. Instead, victims tend to experience simple fatigue, malaise, depression, agitation, restlessness, and a general slowing of activity. Cravings can still be very intense during the worst of the withdrawal, but chronic users often quit because the high has started to produce unpleasant effects.
Surprisingly, tolerance to cocaine is also lower on the spectrum than heroin, nicotine, or alcohol. This is likely why its dependence level is not as high as expected, as tolerance and addiction are closely linked.
On the other hand, reinforcement rates for cocaine are considered to be very high – the highest of the four. The high of cocaine is considered to be very pleasant and also produces a feeling of invincibility and high energy levels. These effects are very attractive, but also end in a crash once the effects wear off. This motivates users to immediately come back for more.
The cocaine high is not as noticeable as heroin or alcohol intoxication. It often gives people a serious boost of energy and may cause them to become very active and talkative. They may actually appear to simply be in a very good mood.
What Does It All Mean?
A grand total of 23.5 million Americans are considered to be in need of treatment for addiction, according to the National Institute on Drug Abuse. Looking at the data, although nicotine has the highest rate of dependence, heroin has right rates across the board. If you factor in withdrawal symptoms, tolerance development, reinforcement, and intoxication, heroin could be considered the most addictive drug. It also tends to cause more general harm than nicotine – a factor that many experts include in their analysis of drug addiction. One particular ranking based on harm to the user and to other people, including society at large, ranked alcohol as its top substance, far ahead of both heroin and cocaine.
On an individual level, it’s impossible to tell which drug will be the most addictive. People can have immediate adverse affects to drugs like heroin and cocaine, keeping the risk of becoming addicted to these drugs at bay, but they may end up with a severe addiction to caffeine. There are also many human factors that play into the risk of developing any kind of addiction, including genetic factors, environment, mental health, and body type. No matter who you are, however, the risk of addiction is always present if you choose to abuse a drug.