Introduction: A Fresh Look at Monoamine Oxidase Inhibitors for Depression

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According to the World Health Organization (WHO), depression is currently a leading cause of disability worldwide, affecting 121 million people, and is expected to be the second greatest cause of disability by 2020. Depression is a complex disorder, and individuals with depression have varying symptoms, history, illness course, and treatment response.

Due to its heterogeneity, depression can be classified into subtypes that encompass specific symptoms, and identifying the subtype can help clinicians determine the direction of the treatment plan for some patients.