Eventually dog, knowing what horror was coming, would get upset as evening approached.
Owners, on the advice of a dog-psychiatrist, put dog on antidepressants to cure the upsettedness.
It's emblematic of something.
What this whole scenario illustrates is that the dog's suffering depression was due not to any chemical imbalance but to it being in an environment radically unsuited to its deep-seated psychology. So, the dog's case, I would argue, is a case of anti-depressants being over-prescribed. The people were being cruel to the dog. They should have stopped being cruel.
I'm writing all this because the dog's owners were on anti-depressants too, presumably to ameliorate their suffering. Perhaps they've created just as bad an environment for themselves as they have for the dog. Is it better for them to have the medication or to suffer? I say, that may be a false alternative.