There are several different theories about the causality and development of bulimia

        Bulimia is eight times more likely to occur in people who have relatives with eating disorders. Parents of people with bulimia appear to be more likely to have psychiatric disorders than people without the disorder. Some experts believe that genetic factors may influence more than half the variances in eating disorders. Several family and twin studies suggest that bulimia nervosa runs in families. Women with bulimic or anorexic female relatives are four to five times more likely to develop the disorder, and twin studies reveal that the genetic risk factor may be as high as 58 percent. These findings are evident in the case study and may contribute to the causality of Carla’s condition. The hereditary evidence is that Carla’s sister had recovered from Anorexia Nervosa and her mother had been diagnosed with depression and co-morbid Obsessive Compulsive Disorder. This disorder can be hereditary and a study by the National Institute of Mental Health revealed that many people with bulimia nervosa exhibit obsessive behavior as severe as diagnosed obsessive compulsive disorder (OCD). OCD is often associated with unusual eating behaviors.

        Another major theory surrounding the development of bulimia is environmental and social influences. Eating disorders in general have a great association with the Western cultures obsession with slimness as an indication of beauty and success. In this society great emphasis is placed upon diet and appearance. Young women believe that if they achieve thinness then they have accomplished a major cultural and personal triumph. This portrayal of thin equals beauty is heavily emphasised in the media through the appearance of celebrities and role models. In theory, social attitudes towards beauty and weight loss produce unrealistic body images in people who develop bulimia nervosa. A bulimic's ideal body image makes them believe they are  heavier than they  actually are. The case study discloses that Carla felt extreme pressure to lose weight from her family, peers and netball team coaches. Research has shown that female atheletes involved in competitive sports are at risk of developing an eating disorder as great emphasis is placed on maintaining an athletic physique and appearance. The case study also tells us that Carla’s family placed pressure on her to lose weight. Research has shown that over half the families in which an individual develops an eating disorder were likely to place a strong emphasis on physical appearance and weight. (Haworth and Hoeppner, 2000). Due to social pressure, thinness and weight loss are proritised and a person’s self-worth becomes based upon maintaining a low weight and striving to become thin. This process is known as a weight-related self-schema and once this is established in a person all thoughts and feelings are centralised around weight and shape. This then usually develops into a fully- fledged eating disorder such as bulimia or anorexia nervosa. Other influences in the development of this schema that is evident in the case study may derive from the fact that Carla’s sister had recovered from Anorexia Nervosa. As this is an eating disorder a great emphasis would have been placed on weight within Carla’s family during her sisters illness and probably thereafter Subsequently this exposure may have contributed to the development of her bulimia.