Co-morbidity is common among patients with eating disorders (ED) and some previous studies have reported a prevalence of over 80%. However, research in the area has been sparse and no previous studies include both children and adults, and both genders.

Data from the Stepwise quality control database, a large-scale Internet based data collection system for specialized ED care in Sweden, were used. The database includes data from children and adults and both genders. Stepwise contains structured diagnostic interviews for ED- and other DSM-IV Axis I diagnostics (the Structured Eating Disorder Interview and the M.I.N.I.Kid and SCID-I interviews). Part one is performed by trained staff and contains SEDI and SCID-I. Part two is made up of self-rating questionnaires and contains EDE-Q, and CPRS. The system is used in 32 treatment units (in and out patients) and comprises up to date1917 patients from all over Sweden.

96,4% of the patients with ED was women and 3,6% were men. 74,8% of the patients with ED also had at least one other Axis I disorder. The most common type of diagnosis was anxiety (61%) followed by mood disorder (56%). 19% had substance use disorders. No gender differences regarding co-morbidity or specific ED diagnosis were observed.

This study confirms previous results showing that the prevalence in co-morbidity is high among patients with ED. The high level of co-morbidity in patients with ED may change the approach in treatment and calls for more tailored treatment programs.