[The Barbie-Matrix: effectiveness of a school-based German program for the primary prevention of anorexia nervosa developed for girls up to the age of 12].

More than 25 % of the 12-year-old girls in Thuringia (Germany) show problematic eating behaviour as measured with the Eating-Attitudes-Test (EAT-26D), which corresponds to an increased risk for the development of anorexia nervosa or bulimia nervosa. This was the starting position of a controlled study using a pre-post-design to check the effectiveness of a newly developed German program for the prevention of anorexia nervosa in girls ("PriMa"). 42 Thuringian schools (20 as treatment group) with 1006 girls participated in the pilot study, which lasted from September 2004 to July 2005. Program effectiveness was analysed with mostly standardized questionnaires at three times of measurement (before, after the intervention and at 3 months follow-up) referring to body related self esteem (FBeK), satisfaction with body shape (KEDS), eating behaviour (EAT-26D) and body related attitudes. The program was established in 9 x 90-minute lessons including interactive exercises and discussing especially developed posters that show scenes of a Barbie-doll's life including the reports of a patient suffering from anorexia. Significant improvements on all variables could be reached for the higher risk group (EAT-26D >/= 10 points; = 26,7 %). Mean values in the EAT-26D decreased 5 points at the average which is equivalent with 6.6 % of the EAT-26D range, reflecting a practically significant change effect.