It might be. Take him to the vet to make sure he's okay. It's a dumb answer that I heard from somebody.
Depends which psychiatric illness...
A symptom is a characteristic of illness, to which the antonym would be normality.
There could be many reasons why a dog is pacing and walking into things. He should be seen by a veterinarian as soon as possible. It may be a symptom of poisoning or he may have another health problem. It may also be a symptom of a stroke or of sudden blindness.
Yes
Hepatitis A
Not eating is a symptom of mental illness. It can also be a symptom of other medical problems. Since it is a symptom, it is extremely difficult to determine if it is a cause.
I would say its a symptom of something. You should get an appointment with the vet.
Cachexia
Yes, Diarrhea is a symptom of a disease or illness
This is likely a hallucination, which is a symptom of mental illness.
A fever is a sign of an illness, since it can be measured objectively.
Pain is a symptom. It presents itself during illness or injury.