https://www.youtube.com/watch?v=XiCrniLQGYc Hei. I think it is a pun. - Depression is depicted as a Dog. - Mongrel means "bastard dog", ie when dogs are not "pure race" (just Image search) > So, Depression is "an equal opportunity bastard", and here Bastard is clearly derogative Note. The image of a Black dog to depict Depression is not casual. Black dogs are a symbol of the ancient mediterranean (taken up by the Greeks) - goddess Hekates, representing the obscure power of the Night -- therefore the Subconscious fears and also Death. Bye

Sorry about the link. I have post a new one which is shared by AP.

The video link doesn't work for me...?