Neurochemical brain imaging studies in bipolar disorder

Objective: We reviewed the neurochemical brain imaging literature in bipolar disorder to synthesize the findings and provide directions for future research. Methods: Relevant articles were retrieved by computerized Medline Ovid search (up to and including 2002) and complemented by bibliographic manual searches of reviews known to the authors. Results: PET and SPECT studies in bipolar disorder have identified changes in various aspects of dopaminergic and serotonergic neurotransmission. Ligands for other neurotransmitters are actively being pursued. Spectroscopy studies have utilized a number of MRS-sensitive nuclei to chemically 'biopsy' the brain of patients with bipolar disorder. Few consistent findings are emerging, however, the majority of nuclei that can be measured are not directly related to the pathophysiology of the disorder. Conclusions: Brain imaging has the potential to unravel the neurochemical underpinnings of bipolar disorder, however, there is a continuing need for clinical, technical and methodological sophistication.