In a research study conducted at the University of Minnesota, researchers found that children placed in non-parental homes, such as foster homes, showed significant behavior problems and higher levels of internalizing problems in comparison to children in traditional families and even children who were mistreated by caregivers. According to an article written by Elizabeth Curry titled The five things you should know about how orphanage life affects children  they state that a child who has lived in an orphanage or a home for multiple children, they will have learned survival skills but lack family skills due to them never understanding permanency. Medical and psychiatric disorders
A higher prevalence of physical, psychological, cognitive and epigenetic disorders for children in foster care has been established in studies in various countries. The Casey Family Programs Northwest Foster Care Alumni Study was a fairly extensive study of various aspects of children who had been in foster care. Individuals who were in foster care experience higher rates of physical and psychiatric morbidity than the general population and suffer from not being able to trust and that can lead to placements breaking down.In the Casey study of foster children in Oregon and Washington state, they were found to have double the incidence of depression, 20% as compared to 10% and were found to have a higher rate of posttraumatic stress disorder (PTSD) than combat veterans with 25% of those studied having PTSD.
Foster care is correlated with a range of negative outcomes compared to the general population. Children in foster care have a high rate of ill health, particularly psychiatric conditions such as anxiety, depression, and eating disorders. One third of foster children in a US study reported abuse from a foster parent or other adult in the foster home. Nearly half of foster children in the US become homeless when they reach the age of 18, and the poverty rate is three times higher among foster care alumni than in the general population. By country
Australia
In Australia foster care was known as "boarding-out". Foster care had its early stages in South Australia in 1867 and stretched to the second half of the 19th century. It is said that the system was mostly run by women until the early 20th century. Then the control was centered in many state childrens departments. "Although boarding-out was also implemented by non-government[al] child rescue organizations, many large institutions remained. These institutions assumed an increasing importance from the late 1920s when the system went into decline." The system was re-energized in the postwar era, and in the 1970s. The system is still the main structure for "out-of-home care." The system took care of both local and foreign children. "The first adoption legislation was passed in Western Australia in 1896, but the remaining states did not act until the 1920s, introducing the beginnings of the closed adoption that reached it peak in the period 1940–1975.