Researchers at the University of Gothenburg have spent the past several years asking a question many of us have sensed but rarely named out loud: what's really happening when an adolescent spirals into anxiety, sleeplessness, or a mood that won't lift — and could nicotine be quietly tipping the scales?
Their answer, drawn from three studies involving several thousand Swedish teens and parallel experiments in rats, lands with weight: nicotine use is consistently linked to worse mental health outcomes, and girls appear especially vulnerable to the fallout.
The picture the data paints
The Gothenburg group surveyed nearly 3,000 Swedish high school students and followed about 1,500 adolescents from lower secondary school through graduation. In both samples, nicotine users reported higher rates of anxiety, depressive symptoms, and sleep disruption than their peers, and the smoking group also reported more suicidal ideation. The pattern held across product type — traditional cigarettes and the tobacco-free nicotine products like pouches and e-cigarettes that have quietly become a fixture in school bathrooms across much of Europe.
The figure that stays with me sits inside the gender breakdown. Nearly 80 percent of the girls who used nicotine showed clinically relevant anxiety symptoms — a number that would give any clinician pause. Girls whose tobacco use climbed over the years of follow-up were also more likely to see sleep, mood, and concentration deteriorate in step.
Why the female brain may be especially exposed
The adolescent brain is still under construction — particularly the prefrontal regions that help us govern impulse and emotion. What the Gothenburg animal study, published in Neuropharmacology, adds is a sharper frame: nicotine altered signaling in the amygdala, the brain's emotional alarm system, and reshaped how neurons talked to each other. Those changes persisted even after the nicotine itself had cleared the body. In female rats, the effects were noticeably more pronounced than in males.
It is the kind of detail that should change our clinical reflexes. Physician and PhD student Johanna Andersson, one of the lead authors, points specifically to the rapid rise of nicotine pouch use among adolescent girls — a population we still don't fully understand. Professor Louise Adermark, one of the principal investigators, frames the broader picture: similar patterns showed up across multiple datasets, and the animal work points to biological changes in the brain that could increase vulnerability to anxiety and stress-related symptoms.
What we can — and can't — say yet
Here is where I'd ask us to hold the conclusion loosely. The researchers themselves are careful: they have not proven cause and effect. Socioeconomic stress, alcohol and other substance use, sleep deprivation, and individual vulnerability all shape both nicotine habits and mental health outcomes. The animal work suggests a plausible biological pathway, but human lives are messier than any rat model can capture.
What we can do is use this finding to anchor a question we often skip in the room. When a teenager shows up with rising anxiety, unrestorative sleep, or a mood that keeps sliding, are we asking about nicotine use with the same directness we bring to screen time, school stress, or social media? If the answer is no, that quiet gap is a reasonable place to begin.