Parental abuse damages countless lives, and evidence shows that parents who were abused as children often go on to abuse their own children. Difficulties can also arise with other relationships and with careers, and those who have been victims can suffer from depression. But the problem is not confined to incest and violence - toxic parents can be alcoholics or drug addicts, or those who ignore the needs of their children or overburden them with guilt; and there are those who are simply indifferent or inadequate.