Standard assessment systems like the Diagnostic and Statistical Manual of Mental Disorders (APA 1994) or the International Statistical Classification of Diseases and Related Health Problems (WHO 1992) define Bulimia Nervosa and Anorexia Nervosa as complex syndromes composed of several symptoms (see Appendix for diagnostic criteria). The diagnostic criteria relate to characteristic symptom patterns as well as to aspects of time such as minimum frequency or minimum duration. For example, the diagnosis “Bulimia Nervosa” requires a duration of at least three months with at least two bingeeating episodes per week. Although time is explicitly mentioned, eating disorders are rather conceptualized as state diagnoses. The duration is taken into account rather to control for fluctuations of symptoms over time than to shift attention to the course of symptoms.