If a person went to his primary care physician and complained of symptoms of fatigue, guilt, worthlessness, irritability, insomnia, decreased appetite, loss of interest in regular activities, persistent sadness, anxiety, and thoughts of suicide, I am pretty sure he would leave that office with a diagnosis of Major Depressive Disorder (MDD) and a prescription for Zoloft, Prozac, or another popular selective serotonin reuptake inhibitor (SSRI).

http://psychcentral.com/blog/archives/2014/08/06/6-conditions-that-feel-like-clinical-depression-but-arent/