The Doctor Dolittle delusion, of animals conversing with the sufferer, has not heretofore been reported to occur with heroin intoxication.

This 23-year-old right-handed single male used heroin daily since the age of 19. For 2 years prior to presentation, 1 hour after injecting at least one bag of heroin IV, he developed hallucinations of animals talking to him. The voices would occur simultaneously with moving their mouths. Dogs would bark, cats would meow, and birds would squawk his name. Insects would engage him in friendly conversation. Different pitches of voice were produced from each animal; birds were high-pitched; squirrels, insects, and cats were lower-pitched; dogs were medium-pitched. As his intoxication resolved, the hallucinations also evaporated.

Mental Status Examination: Oriented x 1, able to recall five digits forwards and three digits backwards. Able to remember none of four objects in 3 minutes without reinforcement and three with reinforcement. Able to spell the word “world” forwards but not backwards.

The hallucination of animals talking, coincident with their mouths moving, articulating the words, associated with intoxication with high doses of heroin, with resolution with elimination of heroin, suggests opioid intoxication is the causative factor. The mechanism of zoopsia in Parkinson’s disease has been attributed to dysfunction of the inferior longitudinal and inferior fronto-occipital fasciculi which relay visual information from the occipital cortex to the temporal and the orbitofrontal cortices. Heroin may have induced cortical inhibition, disinhibiting such pathways and thus facilitating these hallucinations. The simultaneous congruent auditory and visual hallucinations suggests a central origin of these, controlling both the auditory and visual system, such as the left superior and middle temporal gyrus, or possibly the cerebellar vermis. What is unique about the current description is that multiple animal and insect species were involved, and that the pitch of their voice was species specific (high-pitched in birds, and low-pitched in rodents and insects). The pitch may reflect the individual’s personal hedonics towards the type of animal or the individual’s interpretations of mass media’s representation of these animals (i.e., cartoons of Looney Toons high-pitched Tweety Bird or Disney’s low-pitched Jiminy Cricket). While it is possibly due to the opioids themselves, heroin is frequently adulterated with fillers which may contain hallucinogenic properties, any of which may have been the pathogenic factor. Autophobia, or the need for social contact, may be the nidus motivating such communicative anthropomorphism. Query as to the presence of such Doctor Dolittle hallucinations in those with heroin or other intoxicants may be revealing.

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