Abstract
Studies on brain morphology, gene expression, and animal models of depression suggest that neuronal cell death is associated with the pathophysiology of major depressive disorder (MDD) ; however, MDD is different from neurodegenerative disorders. Nevertheless, some forms of dementia, such as Alzheimer’s disease and dementia with Lewy body, often present with depressive symptoms. This discrepancy may arise because the operational diagnostic criteria (the International Classification of Diseases, tenth revision [ICD-10] and the Diagnostic and Statistical Manual of Mental Disorders, fifth edition [DSM-5] ) rely on depressive symptoms. To solve this problem, it may be useful to design clinical studies to strategically classify depression as a subtype and confirm the results of clinical research with supportive basic research. In this article, we discuss the relationship between depression and neuronal cell death and the future direction of depression research, considering the recent findings and results of our studies.
