The dictionary defines psychosis as:

“…a mental disorder characterized by symptoms, such as delusions or hallucinations, that indicate impaired contact with reality.”

Psychologists and psychiatrists may argue indefinitely as to where to draw the line between neurotic and psychotic behaviors, and it is no doubt difficult to discern symptomatic differences at that common junction; but, when one focuses upon the outside extremes of each condition, the differences become obvious, even in dogs.

A neurotic dog may exhibit chronic anxiety, fear, hyperactivity, obsessive behavior, and inappropriate responses to stimuli. Truly psychotic dogs, however, are deranged. Their behavior is acute and unpredictable. It ranges the spectrum from manic highs to deep depression, and tends to be dangerous and destructive to the dog as well as to other animals and humans with which the dog comes into contact.

Many of these behavioral characteristics are sometimes exhibited by non-psychotic dogs that are “having a bad day.” Others may be troubled by some distressing ailment that is temporarily affecting their behavior. When the distress is gone, the behavior returns to normal. The difference between these dogs and the truly psychotic animals is that the psychotic animals seem to be completely unaware of the nature of their destructive behavior. The psychotic dog is not misbehaving; it is simply not able to control its actions.

Dogs suffering from psychosis often have periods of intense violent rage for no apparent reason. They injure themselves, attack inanimate objects, and attack anyone unfortunate enough to be in their aggressive path. They often do not respond to outside stimuli. Their moods quickly change from manic to depressive. Some psychotic dogs will not eat to the extent that they will actually die of starvation.

A dog’s erratic behavior more likely to be diagnosed as psychotic if one or more of the following conditions are present in the dog’s history: an accidental overdose of drugs, extensive corticosteroid drug therapy, distemper before three months of age, a serious parasitic infection before six months of age, diabetes, a history of severe beatings, an injury to the spine or the head, and extreme psychological trauma.

The pattern of the occurrences of psychosis in dogs fairly well parallels the occurrence of psychotic disease in humans. Some dogs have a genetic condition that reveals itself with destructive behavior early in life. Others lead normal lives until, at a certain age, serious psychotic behavior is exhibited.

The mental health of dogs is of interest and concern to veterinarians. Some specialize in the evaluation and treatment of these mental diseases, but psychosis in dogs does not enjoy the same level of scientific research that is invested in studying human psychiatric problems. Most owners, while willing to invest considerable sums of money to treat physical ailments with the proven hope of a cure, are not willing to incur similar costs to speculatively treat their dog’s mental disease. Truly psychotic humans receive professional psychiatric care, in a secure residential facility if necessary. Dogs that exhibit serious psychotic behavior are euthanized.