A person who repeatedly overeats then vomits in an attempt to be thin is suffering from _______.

Bulimia is characterized by a cycle of binge eating followed by purging, which can include vomiting, in an attempt to control weight. Individuals with bulimia often struggle with feelings of guilt and shame about their eating behaviors. This disorder is primarily linked to a preoccupation with body image and weight, leading to the extreme measures some people take to avoid weight gain.

In contrast, amenorrhea, which refers to the absence of menstruation, can occur in various conditions including severe weight loss or stress but is not directly related to the behaviors described. Anorexia involves extreme restriction of food intake and a fear of gaining weight, rather than the cycle of overeating and purging. Obesity, on the other hand, refers to excessive body weight but does not specifically involve the behaviors related to binge eating or purging. Therefore, the description of someone who overeats and then vomits as a method of weight control aligns clearly with bulimia as the appropriate diagnosis.