Re: You're making an elementary mistake. The definition of clinical depression is not based on evidence, but consensus opinion. It is whatever it is defined to be. Anyone who is said to be in the state 'truly' is in that state.

References?

Clinical depression is a serious medical illness that negatively affects how you feel, the way you think and how you act.

- http://www.uhs.berkeley.edu/lookforthesigns/clinicaldepression.shtml