Experiences in childhood can have a tremendous influence on wellbeing in adulthood, and on the ways in which illness presents in adulthood. Conversely, illness in a parent, and the way the illness is managed, can have a great impact on the children in the family. This chapter examines these two areas, examining the knowledge base and the implications for practice in adult liaison psychiatry. Child sexual abuse is the environmental factor which has the greatest influence on those areas of adult functioning which are of interest to the liaison psychiatrist. Mental health problems in childhood are common. Some of these conditions are short lived. However, many conditions persist, in varying form, into adulthood, including anxiety, depression, eating disorders and conduct disorder. Children bereaved of a parent have higher rates of morbidity, and substantial numbers meet diagnostic criteria for major depressive disorder in the first year after parental death.