So you feel down.
You visit a doctor.
He doesn’t know you can feel better by just taking a walk and looking at things so he does what he’s been trained to do.
He prescribes you an antidepressant.
The effect of which is to put you into a numb, non-empathetic, zombie like state where you are capable of shooting dozens of your classmates.
One other side effect of which is suicidal tendencies.
That makes perfect sense.
To the criminally insane.