ABSTRACT

True psychosis is a condition identifiable in humans; animals exhibit psychotic behaviour and may or may not suffer from true psychoses. Psychotic individuals may know what they are doing but be unable to judge the significance of their behaviour, a presumably normal characteristic of lower animals. Robbins and Sahakian propose three characteristics – behavioural similarities, common aetiology and similar responses to treatment – as criteria for animal models of human disorders. Acute morphine administration induces hyperactivity in cats, mice and rats, although the required effective doses range over a factor of more than a hundred. In comparing animal models with their human originals, Ellison warns of difficulties in three areas: matching symptomatologies; comparing behavioural units; and the importance of social environments. In support of the model Gallup and Maser offer some of the characteristics as common to catatonic schizophrenics and tonically immobile animals.