Anxiety modulates odour-linked brain connectivity and alcohol dependence risk

Area of Science:

• Neuroscience
• Addiction Research
• Psychiatry

Background:

• Alcohol use disorder (AUD) frequently begins in adolescence and young adulthood, but early neural predictors are limited.
• The olfactory system's connections to limbic and reward circuits offer a potential avenue for understanding compulsive alcohol use.
• Anxiety, a common AUD comorbidity, may influence these neural circuits.

Purpose of the Study:

• To investigate olfactory-reward brain connectivity as a predictor of alcohol dependence and risky drinking in young adults.
• To examine whether anxiety moderates the relationship between olfactory-reward brain connectivity and alcohol-related outcomes.

Main Methods:

• Analysis of multimodal data from 1003 participants (22-36 years) in the Human Connectome Project.
• Resting-state functional MRI to assess functional connectivity in 41 brain regions related to olfaction, emotion, memory, and reward.
• ElasticNet and LASSO models used connectivity features correlated with olfactory function to predict alcohol dependence and risky drinking, with validation on a separate dataset.
• Logistic regression analyzed anxiety as a moderator.

Main Results:

• Connectivity between precuneus-cingulate-accumbens and lateral occipital-hippocampal regions predicted lifetime alcohol dependence (OR = 1.12, P < 0.001).
• Predictive models demonstrated strong performance (AUC > 0.90 training, >0.80 validation).
• Anxiety moderated connectivity, attenuating risk from memory-reward pathways and amplifying risk via inferior frontal-parietal connections.

Conclusions:

• A novel olfactory-limbic circuit is identified as predictive of alcohol dependence in young adults.
• Anxiety dynamically modulates these neural pathways, influencing individual vulnerability and resilience to alcohol use disorder.
• Findings support integrating sensory, emotional, and transdiagnostic factors into neurobiological models of addiction.