Who believed each stage of development included a personal crisis?

The answer is Erik Erikson.

Explanation:

Erik Erikson was a psychologist who developed a structure of psychosocial development. The structure is based on eight stages, in which the individual must overcome a crisis in order to develop as a succesful member of society.

Some of the stages include Trust vs. Mistrust, appearing from birth to about a year old, in which a child must learn to trust adults; and Integrity vs. Despair, which takes place around age sixty, in which older adults must reflect on their lives and achieve a sense of satisfaction.