Social isolation in animal models of relevance to neuropsychiatric disorders

Animal models of social isolation have been suggested to be relevant to several neuropsychiatric disorders; however, social isolation is usually not purely an alteration of social environment, as it often involves such factors as decreased complexity of the environment, loss of tactile stimulation, and increased metabolic demands of temperature maintenance. In this study, female prairie voles (Microtus ochrogaster, a highly social rodent) were assigned to four experimental groups: continued housing with sibs, with or without nesting material; and individual housing, with or without nesting material. Isolation increased serum corticosterone and affected body weight; the presence of the nesting material lowered corticosterone but did not alter weight. There was no statistical interaction between these two factors. In animal models, factors other than specifically social variables may contribute to the physiological response to social isolation, and the various aspects of the stress response may respond differentially to these factors. (C) 1996 Society of Biological Psychiatry.