Klein argued that people who never succeed in working through the depressive position in their childhood will, as a result, continue to struggle with this problem in adult life. For example: the cause that a person may maintain suffering from intense guilt feelings over the death of a loved one may be found in the unworked- through depressive position. The guilt is there because of a lack of differentiation between phantasy and reality. It also functions as a defense mechanism to defend the self against unbearable feelings of sadness and sorrow, and the internal object of the loved one against the unbearable rage of the self, which, it is feared, could destroy the internal object forever.