Although the hippocampus has been found to be smaller in people withdepression, the clinical relevance of this is unclear. We investigatedhippocampal volume (using high-resolution magnetic resonance imaging) and2-year outcome in 57 patients with major depression. The left and righthippocampal volumes of patients with a depression relapse were significantlysmaller than those of healthy controls. Our results support the hypothesisthat the hippocampus is crucial in the outcome of depression.