An animal model of social instability stress in adolescence and risk for drugs of abuse

There is increasing evidence that adolescence, like early life, is a sensitive period in which ongoing brain development can be influenced by environmental factors. This review describes our use of social instability as a model of mild adolescent social stress, its effects on social interactions and on hypothalamic-pituitary-adrenal function over the course of the procedure and in response to new stressors. The effects of social instability are sex-specific, with qualitative differences between the sexes on HPA function over the course of the stressor procedure, and with greater effects in males on behaviour observed during the social instability and greater effects in females on behavioural responses to drugs of abuse into adulthood, long after the stress exposure. The results from investigations with this model of adolescent social stress are discussed in relation to those of studies using other stressor procedures. Elevated exposure to glucocorticoids over the course of adolescence confers sex-specific changes in behavioural responses to drugs of abuse, which may be of relevance for understanding risk factors in people. (C) 2009 Elsevier Inc. All rights reserved.