When I hear exhaustion first thing in the AM, I think adrenal problems. Cortisol levels should be highest around 7-8am and if cortisol is depressed at that time, this correlates with AM fatigue.

Addressing adrenals, thyroid, sleep habits, blood sugar, circadian rhythm disturbances could be huge.

I think the danger is that once a person is deemed to be depressed, every symptom is attributed to this, meanwhile the body might be screaming for help.