This article reviews selected findings of recent histopathological studies conducted on postmortem brain specimens from patients diagnosed with primary mood disorders & age-matched nonpsychiatric controls. The authors first focus on studies of postmortem tissue in which the number & size of primary brain cells & supportive cells are estimated in various brain regions, & then review molecular studies in postmortem tissue that reveal alterations in expression of different protein. They conclude with an overview of the strengths & limitations of postmortem studies in depression. (60 refs)