Addiction is a serious problem, and one that many guys struggle with at some point in their lives. Whether that’s being addicted to a substance like alcohol or drugs, being addicted to sex, or being addicted to something else — even work — when we rely on something too frequently, we’re causing ourselves to fall into a negative state of mental health a lot of times.

Sure, not all addictions are negative, but most of them can become bad habits that impact us in a bad way. And since we want you to understand just how serious of an issue addiction really is, we tracked down the most addictive substances in the world, based off of research, which will help you understand what to avoid at all costs.

Thanks to research from David Nutt, a professor at the University of Bristol, and some of his colleagues, the substances below seem to lead to the most addiction. That means they impact the brain’s dopamine system, which leave people with a pleasurable feeling that, if not commonly fed, can cause withdrawals.

After seeing the results, we answer a variety of questions about addiction, while revealing the results that Dr. Nutt and his colleagues found to be the most addictive substances in the world.

How is addiction defined?

As stated above, addiction is more than substance abuse, as it can pertain to things like sex, work and even eating. In essence, addiction is anything that a person becomes reliant on, and is officially defined by the American Society of Addiction Medicine (ASAM) as the below:

Addiction is a primary, chronic disease of brain reward, motivation, memory and related circuitry… This is reflected in an individual pathologically pursuing reward and/or relief by substance use and other behaviors… Addiction is characterized by inability to consistently abstain, impairment in behavioral control, craving, diminished recognition of significant problems with one’s behaviors and interpersonal relationships, and a dysfunctional emotional response. Like other chronic diseases, addiction often involves cycles of relapse and remission. Without treatment or engagement in recovery activities, addiction is progressive and can result in disability or premature death.

So, while many people think that substance abuse is the only type of addiction, that’s not the case. It may be the most common and, potentially, most dangerous, but there are many forms of addiction that people need to be educated about.

How fast can someone develop an addiction to something?

There’s no easy answer to this question, as addiction can occur differently in people. For instance, a person who becomes addicted to a drug has several influencing factors, most notable being biology (your genes, for example), age, gender, environment and social interactions. That’s why, in some cases, people may get hooked on the feeling of taking a drug after just one or two tries, while others are more tolerant and avoid developing bad habits if they occasionally use.

Although there’s no direct way of knowing just how fast someone develops an addiction, there are some clues that are important to know and understand, with the most critical being a person’s family history with addiction.

So addiction is hereditary?

In short, yes, but it’s not all the time.

For instance, the risk of developing an addiction is higher in people whose parents or other family members abused a substance, but it’s not guaranteed that those people will abuse the same thing that their relatives before them did, it’s just that they are more likely to, based off of their interactions being around those addicts while younger.

Addiction isn’t something that’s necessarily a chemical in your brain or a certain blood type when you’re born, predetermining that you’ll become an addict. But because people related to addicts are surrounded by “addictive personalities,” it becomes more common and more likely that they, too, will develop an addiction of some sorts.

What are the most addictive substances in the world?

Back to the research mentioned above from Dr. Nutt and his colleagues, who were on the hunt for the most addictive substances in the world. Based off of their findings, here’s what their research showed.

  1. Heroin
  2. Cocaine
  3. Nicotine
  4. Barbiturates (“downers”)
  5. Alcohol

While most of us avoid some of the heavier substances found on that list — like heroin, cocaine and downers — common substances like nicotine and alcohol are just as dangerous, so it’s important to use in moderation or, even better, not at all.

To find out more about the impact of each of the most addictive substances, head on over to CNN, where they break down some of the research from Dr. Nutt even more in order to better understand the impact they can cause on a person, and why they can lead to addiction.

How can I get help with my addiction?

There are a number of different places where a person can get help with their addiction, no matter what kind of addiction it is.

While alcohol or substance abuse is the most common type of addiction, there’s also gambling addiction, sex addiction and, yes, even smartphone addiction, which can all lead to negative mental health issues that cause you frustration. When you feel like you’re becoming to reliant on something, it may be time to talk with someone by seeking professional help.

This means calling an addiction hotline, finding an online therapist who specializes in addiction, going to see a counselor regularly, join a treatment center or addiction support group, or seek outside treatment that requires time away from work and your regular routine. All of these options are available, it’s just a matter of asking for help if you feel like your addiction is beginning to consume you.