Introduction
mania/hypomania, depression, Bipolar disorder, mania
DISORDER
Bipolar disorder (BD) is characterised by recurrent episodes of depression and mania/hypomania, affecting not only mood, but motivation, cognition, and behaviour (APA Theoretical models of BD propose emotional regulation (ER) difficulties to contribute to its underlying psychopathology. These difficulties are proposed to lead to emotional extremes and mood dysregulation, ultimately giving rise to its characteristic pathological mood states (i.e. mania and/or depression) (Townsend and Altshuler Unravelling lithium’s effect on core psychological processes impaired in BD, such as ER, can further elaborate on the mechanisms whereby lithium leads to mood stabilisation in the disorder. Here we used an experimental medicine approach with healthy volunteers which allowed the direct assessment of lithium’s effects unconfounded by changes in clinical symptomology. The present study therefore assessed brain activity as well as an explorative analysis of connectivity during ER in healthy participants administered either lithium or placebo for 10–12 days in a double-blind randomised design. It was hypothesised that:lithium would increase activation in PFC and posterior parietal areas during active reappraisal (enhanced cognitive control) and/or decrease activation in amygdala and temporal regions (decreased emotional reactivity) andlithium treatment would result in greater connectivity between critical nodes of this network, in line with the proposed effects on ER.