Mental health is different.
It holds different thoughts, different values, different insecurities.
In some it is the manifestation of not being pretty or smart 
The feeling of being alone or unable to say,

Please.

For medical students, it is the trauma we see in the hospital
The problems we hear
The conditions we learn about
It is the recognition of symptoms, the knowing of the unknown
It is the pressure of exams, the pressure of constant competition with those you love, hate and. 

Fear.

It is the comparison of z values and centiles, ranks and scores
It is the absence of,

“hey, how are you today?”