This chapter focuses on how recent advances in neuroimaging methods have increased our understanding of a key treatment for bipolar disorder, lithium. Structural magnetic resonance imaging (sMRI) studies suggest that lithium normalises both global and regional reductions in grey matter volume associated with bipolar disorder, while diffusion-weighted imaging (dMRI) studies have shed light on lithium’s potential to rectify abnormalities in white matter integrity. We describe the advent of direct imaging of lithium distribution in the brain using multinuclear MRI techniques (7Li-MRI) which is the first report of noninvasive imaging of a psychoactive drug in its target organ. The spatially heterogenous distribution of the 7Li-MR signal may suggest that lithium directly influences brain structure and function based on lithium tissue concentrations and initial work combining 7Li-MRI and dMRI support this hypothesis. Future directions of research are discussed, including harnessing the potential of multi-modal imaging and longitudinal study designs to develop combined biomarkers or biosignatures of response to treatment. Using lithium as an example, technological and scientific advances in brain imaging can facilitate treatment development and a personalised medicine approach in bipolar disorder.