Effect of a single dose of lorazepam on resting state functional connectivity in healthy adults.

Lorazepam is a fast-acting benzodiazepine that is widely used to manage anxiety symptoms through modulation of GABAergic activity. Despite being one of the most prescribed benzodiazepines, the effects of a single dose of lorazepam on brain functional connectivity at rest is not known. In this placebo-controlled, crossover study, twenty healthy adult participants (9 women; 26.2 ± 5.2 years) underwent two resting-state fMRI (rs-fMRI) scans following administration of either lorazepam (2.5 mg) or placebo. Imaging data were analyzed using an individual brain network parcellation approach and differences in functional connectivity among 78 individual-specific ROIs were estimated. Compared to placebo, functional connectivity was reduced following administration of lorazepam between the left medial paracentral lobule and left temporal pole and between the left posterior cingulate sulcus and right cuneus. Reduced connectivity within higher-order cognitive networks partly supports what has been reported for other benzodiazepines such as midazolam and alprazolam. However, differences across benzodiazepines - possibly due to pharmacokinetics, dosage and receptor selectivity - underscore the need for further research.