Building on findings from animal studies, pediatric clinical trials, epidemiologic research in adults, and on preliminary findings from the investigators' laboratory in children and adolescents, this project aims to investigate whether selective serotonin reuptake inhibitors (SSRIs), a group of widely-used psychotropics, are associated with impaired bone mineralization in youths. Establishing such an association is a first step in a process that would eventually involve developing preventative interventions. Identifying genetic factors that place certain youths at higher risks for this side effect would ultimately allow clinicians to tailor treatment to the needs and vulnerabilities of each youth, moving the field closer towards individualized medicine.