A comprehensive new study contradicts claims about nicotine’s supposed harmful effects on the brain, revealing that nicotine use is an effect – rather than the cause – of variations in brain structure.

The study, published in the Journal of the American Medical Association (JAMA), analyzed brain images of nearly 10,000 adolescents aged 9 to 11 and followed them for three years to see how their brains are affected when they use different substances.

The results showed that adolescents who started using substances before the age of 15 had differences in brain volume, thickness, and structure compared to those who did not use substances. 

Brain differences appear before nicotine use

The findings reveal that the structural differences in the brain linked to early nicotine use were often present even before adolescents tried these substances.

“This adds to some emerging evidence that an individual’s brain structure, alongside their unique genetics, environmental exposures, and interactions among these factors, may impact their level of risk and resilience for substance use and addiction,” said Dr, Nora Volkow, head of the US National Institute on Drug Abuse (NIDA) in a statement.

Dr. Claude Guiron, Scientific Director of Swedish Match in the Nordic region, believes the study is an important contribution to better understanding the causal relationship behind the differences seen in brain structure between nicotine users and non-users.

“The study clearly shows that the brains of users of nicotine and other addictive substances look different already in childhood, long before they have used any addictive substances,” he tells Snusforumet.

“The changes seen in brain appearance are therefore not brain damage, as is sometimes claimed.”

Misunderstanding correlation and causation

Nicotine opponents frequently claim that changes in the brain structure of nicotine users are caused by nicotine itself. However, the new research indicates such claims are built on a common misunderstanding of correlation and causation.

“The study provides further support for what is called the ‘common liability theory.’ It explains why users of a substance like nicotine are also at an increased risk of using other substances, such as cannabis,” says Guiron.

“According to this theory, the cause is not the nicotine itself but entirely different common factors. The use of different substances has a shared underlying cause, which can be genetics, environment, other lifestyle factors, and, as this study clearly shows, differences in brain appearance and function already in childhood.”

A call for science-based public health policies

Patrik Strömer, Secretary General of the Association of Swedish Snus Manufacturers, welcomes the findings. He hopes the new study will force nicotine opponents to stop spreading misinformation about the relationship between nicotine and the brain.

“Youth under 18 should not use nicotine, just like those with certain medical conditions and pregnant women,” he tells Snusforumet.

“But claiming that nicotine damages the brain is propaganda, not science. And now there is independent research confirming this,”

A better future with harm reduction

The study’s conclusions also serve as a reminder of the importance of basing public health policy on robust science rather than assumptions or ideological beliefs.

“The fact that brain structure plays a crucial role in whether someone starts using substances means that many previous conclusions about nicotine need to be reevaluated,” says Strömer.

“If we want to save lives and reduce tobacco-related harm, it’s time to build our public health policy on facts, not prejudice.”