“Addiction is Not Always Harmful” – Professor on What Addiction Really Means and How it Compares with Dependence

Professor Fredrik Nyström is a senior consultant physician and Professor of Internal Medicine at Linköping University, Sweden. With more than 36 years of clinical experience in endocrinology, he has studied hormones, obesity, diabetes, and cardiovascular disease. In 2025, he published the book "Lighten the Load on Your Shoulders", where he challenges common health myths using scientific evidence.
We met Professor Nyström to discuss addiction, dependence, and why the words we use matter more than we think.

Professor Nyström, before we get into nicotine and snus, let’s start with the basics. What do we actually mean by addiction? Is it, by definition, something harmful?

"Not necessarily. Whether a dependence is harmful or not depends entirely on what kind of dependence we are talking about. We usually distinguish between physical dependence and psychological dependence. That distinction is crucial.

A purely physical dependence can, for example, involve medicines that a person needs in order to remain healthy – drugs used to regulate blood sugar, blood pressure or cholesterol. In those cases, you are “dependent” on the medication in the sense that if you stop taking it, the underlying condition returns. The dependence simply reflects a bodily need for the substance in order to function properly.

Psychological dependence is different, and in professional terms, usually labelled addiction. An addiction includes craving or longing – a mental or emotional pull towards something that makes a person feel unbalanced without it. In this context, the addiction negatively affects the persons behaviour, which can’t fully be controlled."

So the way we define dependence actually varies?

"Yes, very much so. In English, this distinction is often reflected in language. The term addiction is typically used for psychological dependence, while dependence more often refers to physical dependence.

A classic example of harmful substance misuse is alcohol addiction. One of the diagnostic criteria is that the individual continues drinking despite serious consequences – such as losing their job or damaging relationships – rather than enduring being without alcohol. In those cases, people usually suffer from both physical dependence and psychological addiction. You might develop abstinence symptoms such as severe anxiety and, as is well known, alcohol addiction has several mental and sociological drawbacks."

But surely my morning craving for coffee wouldn’t count as misuse?

"That’s a very common and very reasonable question. You can certainly be dependent on caffeine without that dependence amounting to misuse or harm as in severe addiction.

In medicine, we use diagnostic classifications – ICD-10 codes¹ – to describe different forms of dependence. Nicotine dependence, for instance, is included in code F17.2. Caffeine-related diagnoses also exist and fall under stimulant-related codes, including those that explicitly mention caffeine such as F 15.2 ².

To put this in perspective, consider type 1 diabetes, a diagnosis I have made thousands of times in my career. Its ICD code E10.9 literally includes the term insulin-dependent diabetes. That dependence is purely physical and lifesaving. Without insulin, the person becomes seriously ill. This illustrates very clearly that dependence does not automatically equal something dangerous or negative."

You have previously talked about diagnostic terms like “psychotic disorder” in relation to caffeine, it sounds alarming. Is being dependent on coffee dangerous?

"No, of course not, from a medical point of view. And the same applies to nicotine when it is consumed without smoke – for example through snus or nicotine pouches.

What is dangerous is inhaling cigarette smoke into the lungs to get the nicotine-kick. That is where the real harm comes from. Nicotine itself, whether snus or other non-combustible sources, is not what drives lung disease.

That said, addiction to everyday drugs such as caffeine and nicotine can be inconvenient and costly. Daily coffee or snus use does cost money, and some people dislike feeling reliant on a substance to get a sense of balance that also affects their economy."

What about food and water? Are we dependent on those as well?

"Absolutely. Humans are dependent on food, water and sleep in order to survive and remain healthy. This shows very clearly that dependence can be extremely powerful without being pathological.

Of course, food can be misused if overeating leads to severe obesity. And I have treated patients who drank so much water that they developed dangerous electrolyte imbalances and needed to stay at the hospital. So even essential things can be taken too far – but dependence itself is not the problem. Also, you are dependent on getting a certain amount of sleep, but sleeping too much does not cause you bodily harm. The things that you may be dependent on do not automatically become harmful in large “doses”."

The word “addiction” does carry a negative tone, though – something you should get rid of but can’t.

"That’s true. For most people, becoming dependent on caffeine or nicotine feels like an unwanted side effect. But medicine is full of examples where what was once considered a side effect later turned out to be useful.

Early antihistamines caused drowsiness – initially seen as a problem – but that very effect is now used therapeutically as a mild sedative that does not cause dependence. Another well-known example is the blood-pressure drug minoxidil that was later found to reduce hair loss and is now marketed, and very popular for that purpose.

Even opioids, which are highly addictive, cause constipation as a side effect – and drugs from the same group are among the most effective treatments for severe diarrhoea. Some of my patients are physically dependent on them simply to be able to leave their homes.

So, deciding what counts as a “side effect” versus a benefit is often a philosophical or ethical question."

Is nicotine dependence itself harmful? Many authorities often seem to suggest that it is.

"Many people believe that, but as a researcher in this field, I question that assumption. In Sweden, nicotine consumption has largely shifted from smoking to snus – particularly nicotine pouches.

Today, adult smoking rates in Sweden are around five per cent, which the WHO defines as a non-smoking population. Total nicotine intake is roughly similar to when about 20 per cent smoked, but public health outcomes have improved dramatically. Rates of cardiovascular disease and lung disease, such as COPD, have fallen.

This makes it essential to distinguish how nicotine is consumed when discussing harm."

Are some people more sensitive to nicotine or caffeine than others?

"Yes, very much so. There are clear individual – and also genetic – differences. Not everyone who tries snus or smokes becomes addicted. The same applies to coffee.

Some people enjoy coffee occasionally without ever developing withdrawal symptoms. Others feel distinctly unwell without their morning cup. That feeling of needing access in order to feel balanced is often what people find most irritating about addiction and dependence."

You have conducted research on what happens when people stop using snus. Do people become healthier?

"One might assume so, but our data did not support that. In a controlled study of 50 snus users, we measured blood pressure and blood markers while they were using snus and then followed them for three months after stopping.

Seventy-four per cent managed to quit cold turkey without any particular help from us professionals who ran the trial, which in itself was very noteworthy – stopping snus was not nearly as difficult as is often claimed. However, those who stopped did not show any measurable health improvements.

On the contrary, blood pressure measured by the snus users themselves increased slightly, average weight rose by about two kilograms, and markers for mean blood glucose, cholesterol and inflammation shifted in an unfavourable direction, though modestly.

In short, none of the measured parameters improved. If anything, participants would likely have been better off continuing to use snus, at least in the short term."

Why do your findings differ from what we often hear in the media?

"Much of the narrative around snus is based on observational studies, which cannot establish cause and effect. These studies are useful for generating hypotheses, but they are frequently misinterpreted. Also, most people in Sweden who now use snus and seem to develop harmful cardiovascular effects are former smokers who switched from smoking to snus. In a population that I have data on several thousands they are a great majority of snus users. My population data set consists of five thousand middle aged Swedish subjects. Some are former or current smokers and the great majority of those that use snus now are previous smokers

Their former smoking continues to add an increased risk for many diseases the rest of their lives, even though they quit smoking.  Increased calcium deposits in arteries and destroyed alveolae in the lungs, caused by smoking in the past, sadly cannot heal. That’s just how the immune system and body works. Many tissues can not revert to normal again despite the fact that the initial cause of the harm has ceased to exist.

Behavioural changes tend to cluster. Someone who quits snus may also change diet, exercise more, reduce sugary drinks, or experience changes in personal life that improve health. You cannot isolate the effect of snus cessation without controlled studies in which you study subjects before and after using snus. Unfortunately, those nuances are often lost in media reporting. Strangely nobody in Sweden has done and published a trial such as ours, before."

So, to sum up: how dangerous is nicotine addiction, really?

"When nicotine is consumed without smoke, it is not particularly dangerous at all. It is far more comparable to drinking coffee than to smoking. Coffee also seems to have a slight weight reducing effect and to reduce risk for diabetes. Both substances increase the sense of peppiness and focus, at the right individual doses.

Snus may even help some people maintain weight and slightly lower blood pressure. And importantly, it is much easier to quit than smoking – likely because nicotine delivery from snus is slow, whereas cigarettes deliver nicotine to the brain within seconds.

Snus use is not a dangerous form of substance misuse, especially when compared with smoking. For many people, it simply adds a small pleasure to everyday life – much like a good cup of coffee."