On my hobby horse again -
I believe that "depression" was put forward as a "non-homicidal" explanation / diversion by those with a vested interested in it not appearing to be a homicide.
I agree with your post 100%. I hope people realise that I've only raised the subject to point out that "someone" appears to have implied that "depression" may have played a role in Allison leaving the house that night. I am by no means suggesting that is true.
It just makes me wonder what else they may have done/said in support of their "story" to imply this was the case.