According to Pet Medicine Alberta, dogs can suffer from mental illness which sometimes manifests as the canine equivalent of autism. Symptoms can display as early as 5 weeks old. Because mental illness in canines is rare, dogs are often misdiagnosed with behavioral problems.
The most common causes of mental retardation are genetic (in-breeding), disease or injury. Depression, autism, separation anxiety and obsessive-compulsive disorder are all mental illness conditions that can be misdiagnosed by an uneducated pet owner. Pet Medicine Alberta explains that there are various treatments available for these conditions, including medication for obsessive-compulsive disorder, desensitization training for separation anxiety and an animal companion for a depressed pet. Above all, patience and consideration by the owner are recommended for a mentally ill or "retarded" dog.