Animal models of human disease play a central role in modern biomedical science. Developing animal models for human mental illness presents unique practical and philosophical challenges. In this article we argue that (1) existing animal models of psychiatric disease are not valid, (2) attempts to model syndromes are undermined by current nosology, (3) models of symptoms are rife with circular logic and anthropomorphism, (4) any model must make unjustified assumptions about subjective experience, and (5) any model deemed valid would be inherently unethical, for if an animal adequately models human subjective experience, then there is no morally relevant difference between that animal and a human.

Neuropsychological impairment and DSM-III-R Axis I psychiatric diagnoses were evaluated in a heterogenous group of HIV seropositive individuals and seronegative individuals with similar risk factors for HIV infection. Neuropsychological and psychiatric disorders were common in the HIV seropositive group, but there were no relationships between these two aspects of neuropsychiatric dysfunction in seropositive patients. Results indicate that psychiatric disorders in HIV seropositive individuals tend to predate infection and decrease over time following knowledge of seroconversion, suggesting that they are primarily a function of psychosocial factors. Neuropsychological disorders are specific to HIV seropositive patients and tend to increase over time following seroconversion, suggesting that they are due to neurological effects of HIV-infection. (JINS, 1995, 1, 581–588.)