I wondered if "depressed" could have been thrown in there because they knew she had reportedly just had an argument...
I don't believe so. Since Mother is at precinct reporting her missing, I believe the clothing described, what was in her possession such as glasses, ring, handbag, etc., as well as the description of her mental state, would be what the Mother last observed upon her daughter leaving the home.
To use term Depression implies, IMO, she noticed more than a typical sadness, for a few days.