Main areas of interest are pastoral theology and psychology, psychology of religion, narrative approaches, trauma, sexuality, and popular culture. Have published or edited 16 books and more than 130 scientific or professional publications.

He was president of the International Academy of Practical Theology and of the International Society for Empirical Research in Theology.

Since June 2011, He is also a member of the Upper Chamber of the Dutch national parliament for the Green party GroenLinks.