This study examines if the use of antipsychotic medications might contribute to an interruption in bone mineral development and/or a reduction in bone mineral content in adolescents.

Studies have shown that some antipsychotic medications, including Risperdal, can increase prolactin levels in both adult and pediatric populations. Prolactin is a hormone made by the central nervous system. The main function of prolactin is to regulate lactation in females. However, having too much prolactin over time can interrupt bone mineral accrual and a decrease in bone density. Since peak bone mass is reached during adolescents, this is a key determinant of a lifetime risk of osteoporosis. On the other hand, there ahve been no reports of increased prolactin using Abilify. In fact, in adults Abilify has been shown to normalize or even lower prolactin levels. In this study, we will compare the amount of prolactin and bone mineral density of adolescents who take Risperdal or Abilify with bone mineral density of adolescents who do nto take antipsychotic medications. We will also compare the amount of prolactin and bone mineral density of adolescents who take Risperdal with those who take Abilify. This study will also help us to learn about the relationship between medications, prolactin levels, sex steroids, and bone formation markers in adolescents.

Inclusion Criteria:

• Between the ages of 11 and 17 years
• Females and males on aripiprazole or risperidone monotherapy for minimum one year
• Within 10th and 90th percentile for height and weight

Exclusion Criteria:

• Pregnancy
• Chronic illness such as asthma, inflammatory bowel disease, rheumatoid disorders or cystic fibrosis, on chronic systemic steroid therapy for past 12 months
• Menstrual irregularities secondary to excessive physical activity
• History of anorexia nervosa and/or bulimia nervosa
• Subjects on hormonal contraception

Subjects will be recruited from psychiatry clinic and community resources