Cannabis Impairs Attention While Nicotine Enhances It, But Both Harm Developing Brains | Research

The takeaway

A comprehensive review found that cannabis/THC generally impairs multiple aspects of attention in adults, while nicotine tends to enhance it, but prenatal exposure to either substance is linked to attention deficits and behavioral disorders in offspring.

Neuropsychologists, addiction researchers, prenatal care providers counseling on substance use.

Cannabis impairs and nicotine enhances adult attention, but both harm prenatal brain development

What the researchers found

Cannabis impairs selective attention and creates attentional bias toward cannabis cues. Reaction time effects depend on timing of last exposure. Preclinical studies show cannabis-induced attention deficits persist after abstinence. Nicotine has dose-dependent effects on attention. Prenatal exposure to either substance increases risk for ADHD, attention deficits, and impulsivity in offspring.

Why it matters

Cannabis and nicotine are among the most commonly used substances and are often co-used. Understanding their opposing effects on attention in adults and shared harmful effects on prenatal development is important for clinical guidance and public health messaging.

The numbers in context

Review covers preclinical and clinical studies across all developmental periods; prenatal cannabis exposure linked to increased ADHD, schizophrenia, and drug-seeking risk in offspring; prenatal nicotine exposure shows sex differences with males more affected.

How the study worked

Narrative review synthesizing preclinical and clinical findings on THC and nicotine effects on selective attention, sustained attention, visuospatial attention, attentional bias, and attentional disorders across all developmental stages.

What this study cannot tell us

Narrative review methodology. Preclinical and clinical results may not be directly comparable. Dose and timing of exposure vary widely across studies. Co-use effects are understudied.

How to read the evidence

Moderate: Comprehensive narrative review spanning preclinical and clinical literature across developmental stages, though narrative methodology is less rigorous than systematic review.

When this study was published

Published in 2025.

The bigger picture

The opposing effects of THC (impairing) and nicotine (enhancing) on adult attention may partly explain why they are commonly co-used. Their shared prenatal harm, despite opposite adult effects, highlights that developmental neurotoxicity operates through different mechanisms.

Questions still open

Do the opposing effects of THC and nicotine on attention interact when co-used? Why do both substances harm prenatal attention development despite opposite adult effects? Are there sex-specific attentional effects of cannabis that mirror nicotine findings?

Common questions

How does cannabis affect attention?

Cannabis impairs selective attention, creates attentional bias toward cannabis-related cues, and in preclinical studies produces attention deficits that persist even after stopping use. The effect on reaction time depends on how recently cannabis was used.

Why are prenatal effects different from adult effects?

During fetal development, both substances interfere with the formation of neural circuits critical for attention, regardless of their opposing effects in the mature brain. Prenatal exposure to either substance increases risk for ADHD and other attentional disorders.

Read the original research

The Effects of THC and Nicotine on Attention: A Narrative Review.

Current topics in behavioral neurosciences, 75, 183-238

View on PubMed ↗Publisher’s paper ↗

Citation

Oleszak, Kennedy; Striegel, Lily Freeman; Roeder, Nicole; Mohr, Patrick; Penman, Samantha; Collins, Lorraine; Smith, Danielle M; Thanos, Panayotis K. (2025). The Effects of THC and Nicotine on Attention: A Narrative Review.. Current topics in behavioral neurosciences, 75, 183-238. https://doi.org/10.1007/7854_2024_568