To impress the diversity of positive symptoms in patients with schizophrenia.

Case report and review of the literature (PubMed).

Male patient, 43 years old, single, elementary school graduate, living with his mother. First hospitalization.

Persecutory ideas and auditory hallucinations dating from 8 months: he was convinced that his neighbor wanted to harm him; for this reason he had recruited his dog. He noted that the dog was following him when he was going out in the neighborhood, and was very aggressive towards him (he“heard” the dog barking at him continuously). His fear made him stop working (scrap dealer) and he was afraid of coming out of his home. He had even thought of poisoning the animal. Laboratory as well as neuroimaging exams (EEG, brain CT) were normal. The patient was treated with haloperidol (30 mg daily) and olanzapine (15 mg daily). He was discharged after 18 days. Three months later, he spontaneously stopped medication (15 mg olanzapine daily); in three weeks time the same ideas had resurfaced and was “hearing” the neighbor's dog barking again loudly at him. Since then he takes his medication regularly without experiencing any symptoms. Only one relevant article was found in the literature (Dening, T.R., and West, A.“The Dolittle phenomenon: hallucinatory voices from animals”, Psychopathology. 1990; 23: 40–45).

Animals could, rarely, play a key role in the delusional ideas of patients with schizophrenia. This doesn’t make these ideas less debilitating or even potentially dangerous.