Individual differences in anxious apprehension and anxious arousal alter resting-state network structure and connectivity

Background

Pathological anxiety is commonly treated as a unitary construct, manifesting as various clinical subtypes. However, there is a growing consensus that anxiety has at least two unique dimensions, anxious arousal and anxious apprehension. Nevertheless, their distinguishable neurobiological mechanisms are unclear. Here, we take a transdiagnostic approach to disentangle network-level functional and structural disturbances at rest, a state when some anxiety symptoms may be most apparent.

Methods

53 adults experiencing a range of anxiety and/or depressive symptoms completed resting-state fMRI. Resting-state networks were identified by independent components analysis. Dual-regression tested anxious arousal and anxious apprehension derived within-network connectivity differences while controlling for depression. FSLNets tested differences in between-network functional connectivity.

Results

Anxious apprehension was associated with expansion of the default and somatomotor networks, while anxious arousal was associated with hyperconnectivity in the salience, limbic, frontoparietal, and default networks. Anxious apprehension was also associated with increased connectivity between the default and salience networks as well as decreased connectivity between the dorsal attention and limbic networks.

Limitations

Evaluating a larger sample size and longer resting-state scans can better ensure reproducibility of results. The cross-sectional design limits conclusions about the temporal dynamics of anxious apprehension and anxious arousal and functional connectivity alterations observed in the present study.

Conclusions

Results suggest that anxious apprehension and anxious arousal have distinguishable neurobiological mechanisms that contribute to maladaptive differences in threat evaluation, stress response, and self-referential thought. These findings enhance our understanding of anxiety's nosology and pathophysiology, informing potential mechanisms for intervention.