Other risks related to the infant's milieu and often found in combination with maternal deprivation
include nutritional deprivation, maltreatment (Johnson, 2000) and experiences that have been characterised as global deprivation (Rutter and the ERA study team, 1998; Gunnar 2001).
Scientists conducting maternal deprivation
studies have long been able to induce permanent changes in the behaviors of animals, notably their responses to stress.
In particular, thorough studies have been carried out on the relationship between an early experience of loss and psychopathology, frequently stimulated by Bowlby's (1951) hypothesis on the negative consequences of maternal deprivation