Three new studies from the University of Gothenburg have linked nicotine use — including tobacco-free nicotine pouches — to anxiety, depression and other mental-health symptoms in Swedish adolescents. Girls appear to be especially vulnerable, and a companion animal study suggests there may be a biological reason why.

The findings matter for the nicotine pouch category because the researchers single it out directly. Johanna Andersson, physician and PhD student at Sahlgrenska Academy and one of the lead authors, said: "We need a better understanding of how nicotine pouches affect mental health, especially among adolescent girls, where the use of nicotine pouches has increased so rapidly."

What the studies found

The research package, released by the University of Gothenburg on 11 August 2026 and covering three peer-reviewed papers, draws on two large adolescent cohorts and a laboratory animal study:

• Nearly 3,000 Swedish high-school students — almost 80 percent of the girls who used nicotine reported clinically relevant symptoms of anxiety. The association held for both traditional tobacco products and tobacco-free nicotine (TFN) products such as nicotine pouches and e-cigarettes.
• Around 1,500 adolescents tracked over time (the LoRDIA program in southern Sweden, followed from lower secondary school through high school) — depressive symptoms and suicidal ideation were more common among adolescents who smoked. Girls who increased their tobacco use over time also showed worsening sleep problems, anxiety, low mood and concentration difficulties.
• A rat study published in Neuropharmacology — nicotine altered communication between neurons in the amygdala, the brain region central to emotional regulation and stress responses, and produced long-lasting changes in brain activity that persisted after the nicotine had cleared the body. The effects were most pronounced in female rats.

The three papers appeared in Tobacco Use Insights (May 2026), Nicotine & Tobacco Research (June 2026) and Neuropharmacology (February 2026).

Why it matters for pouches

Nicotine pouches are tobacco-free nicotine products, and their use has risen sharply among Swedish teenagers — especially girls — even as smoking has fallen. The Gothenburg work is one of the first research packages to look specifically at how tobacco-free nicotine, including pouches, correlates with adolescent mental health, rather than collapsing all nicotine into a single "tobacco" category.

The gender signal is consistent across all three studies: girls who used nicotine reported more anxiety and depression, and female rats showed stronger amygdala changes. The researchers say the marked girl-boy differences warrant further investigation.

Cause and effect is not settled

The studies are observational and questionnaire-based (plus the animal model), so they cannot prove that nicotine pouches cause anxiety or depression. The authors are explicit about this.

Louise Adermark, Professor at Sahlgrenska Academy and one of the principal investigators, said: "One of the key findings is that we see similar patterns across several different studies using different types of data. However, we still cannot determine cause and effect. The animal studies demonstrate biological changes in the brain that could contribute to increased vulnerability to anxiety and stress-related symptoms."

The researchers note that socioeconomic factors, stress, alcohol use, other substance use and individual vulnerability also influence the risk of both mental-health problems and nicotine use. In other words, adolescents already experiencing distress may be more likely to use nicotine pouches — a relationship that runs in both directions. The rat study is the closest the package comes to a mechanism, showing nicotine itself rewiring amygdala signalling in a sex-specific way.

What's next

The findings arrive as the EU consults on its tobacco-control framework revision and as Sweden's own regulators weigh how to handle a market where Folkhälsomyndigheten has recorded rising nicotine-pouch use among 16–29-year-olds. The Gothenburg team frames its work as a prompt for further research on how novel nicotine products affect the developing brain, rather than a settled verdict.

For adult pouch users, the studies do not establish that nicotine pouches cause mental-health harm — the cohorts are adolescents, and the design cannot separate cause from correlation. But they add a new, peer-reviewed data point to a question the category can no longer avoid: what the rapid uptake of tobacco-free nicotine among teenagers is doing to their brains.

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SOURCES:

• University of Gothenburg, "Nicotine use linked to mental health problems in adolescents." 11 Aug 2026. gu.se
• EurekAlert (AAAS), "Nicotine use linked to mental health problems in adolescents." 11 Aug 2026. eurekalert.org
• forskning.se, "Nikotin kopplas till psykisk ohälsa hos unga." 17 Aug 2026. forskning.se
• Andersson et al., "Gender-Specific Associations Between Tobacco and Tobacco-Free Nicotine Use and Symptoms of Anxiety and Depression in Swedish Adolescents." Tobacco Use Insights, May 2026. DOI: 10.1177/1179173X261455075
• "Sex-specific associations between tobacco use and youth mental health: prospective and cross-sectional findings from Swedish adolescents." Nicotine & Tobacco Research, June 2026. DOI: 10.1093/ntr/ntag148
• "Nicotine produces a sex- and subregion-specific hypoglutamatergic state in rodent amygdala which can be reversed by motor-skill training." Neuropharmacology, February 2026. DOI: 10.1016/j.neuropharm.2026.110879