The aim of the present study was to evaluate the behavioral and affective characteristics and the changes in psychosocial functioning resulting from precocious puberty in 15 girls with central precocious puberty treated for 2 y using the GnRH agonist long-acting triptorelin, and in 5 untreated girls. After diagnosis of precocious puberty at 6.6-10.4 y of age, height, weight and pubertal development were evaluated at 3-month intervals over 2 y. Semi-structured interviews were carried out with the patient, the parents and the pediatric endocrinologists at 1, 8, 16 and 24 months after diagnosis. Standardized questionnaires (Child Behavior Checklist, Self-esteem Inventory) were administered at 1 and 24 months or 16 and 24 months, respectively. There was a mean 1.5-y delay between the observation of signs of puberty as reported by the parents and the diagnosis of precocious puberty at the first consultation of a pediatric endocrinologist. Before follow-up, all 20 girls were very concerned about physical differences from peers, particularly breast development. During therapy, breast regression to minimal or absent development occurred in 5/15 treated patients, who then no longer felt embarrassed about pubertal development in contrast to the other patients. Fear of sexuality remained obvious throughout the study in most patients. Feelings of loneliness and exemplary behavior were observed and tended to decrease in the treated patients and to increase in the untreated patients. Elevated scores of withdrawal, anxiety/depression and somatic complaints at Child Behavior Checklist were still observed after 2 y. These changes in behavioral and affective characteristics appeared to be related neither to height and weight, nor to development of pubic hair, which progressed in most patients. After 2 y, the physical differences remained a concern for 13 girls and the risk of short adult stature for 6. In summary, some behavioral and affective characteristics and particularities in psychosocial functioning are observed in girls with precocious puberty. During treatment with long acting triptorelin, problematic behavior and functioning decrease slightly, particularly in the few girls showing breast regression to minimal or absent development.