Purpose of review: Structural brain changes are apparent in some magnetic resonance imaging studies of patients with mood disorders, but results are inconsistent. The focus of this review is to examine whether there are demographic or clinical characteristics of people with mood disorders that are associated with regional brain volume changes. A systematic search of the literature in English, from January 2004 to July 2005, was performed on MEDLINE. References cited in all reports were searched iteratively to identify missing studies.
Recent findings: Recent studies have focused on factors that might help to reconcile the divergent reports of regional brain volume changes in major depressive disorder and bipolar disorder. Small hippocampal volumes are apparent in patients with recurrent major depressive disorder, but not generally reported early in the course of adult onset depression. Small hippocampal volumes may be apparent in patients with childhood onset illness. Small hippocampal volumes are infrequently reported in bipolar disorder, but studies to date have not accounted for illness history or treatment status. Changes in amygdala volumes are inconsistently reported in patients with major depressive disorder or bipolar disorder. There are relatively fewer reports of other brain regions, including the areas of the frontal cortex and striatum. An extensive preclinical literature suggests that various psychotropic medications may have neurotrophic and neuroprotective effects, making documentation of treatment history essential.
Summary: Patients' age, sex, age at onset of disease, course of illness and treatment status may affect the detection of regional brain volume changes in people with mood disorders.