Exploring the Relationship Between Smoking and Brain Functional Connectivity in Schizophrenia
Rohail Kahn
23/02/2026
Schizophrenia is a chronic psychiatric condition affecting around 1% of the global population ((Rizvi., 2024)). Individuals with schizophrenia exhibit higher levels of smoking (80%) than the general population (15-20%) ((Leonard et al., 2007)). Given that schizophrenia is associated with disrupted functional connectivity, this study will determine the relationship between smoking and functional connectivity in schizophrenic individuals. We used an open dataset of a total of 81 participants who were categorized into four groups: non-schizophrenic smokers (n=22), non-schizophrenic non-smokers (n=22), schizophrenic smokers (n=12), and schizophrenic non-smokers (n=25). Resting-state functional magnetic resonance imaging (fMRI) was available. The CONN toolbox was used to analyze the fMRI data to assess for differences in connectivity using ROI-to-ROI and graph theoretic methods in both the whole brain and a subset of ROIs chosen based on prior literature. Functional connectivity analysis controlling for age and sex revealed a significant difference in degree when comparing all groups with an ANOVA, and a followup pairwise comparison showed reduced average degree for the smoking control group compared to nonsmoking schizophrenia group. In the subset of ROIs, we found a statistically significant group difference for global efficiency and degree, and pairwise comparisons revealed reduced global efficiency for the smoking SCZ group compared to the nonsmoking SCZ group when controlling for age and sex. These findings suggest that smoking is associated with differences in brain network function in individuals with schizophrenia.