Just over 20 percent of the sample met diagnostic criteria for PTSD. Adolescents with PTSD were more likely to be female and members of a racial/ethnic minority group. As hypothesized, adolescents with PTSD had higher rates of comorbid disorders, suicidal ideation, and hospital service use compared with adolescents without PTSD. This suggests that adolescents with PTSD require more intensive and extended treatment services. Almost 46 percent of the sample had a history of abuse and neglect, whether or not they were diagnosed with PTSD. Participants were 407 consecutive admissions (242 females) to an adolescent psychiatric inpatient unit in southern New England from February 2002 to February 2003. Due to various exclusions, the final study sample consisted of 377 (60.7 percent females) participants ages 12 to 18. A standard intake evaluation was used to collect the data. Psychiatric diagnoses were conducted with the Children’s Interview for Psychiatric Syndromes, which screens for 20 Axis I disorders in children. Suicidal ideation was identified with the Suicide Probability Scale. The use of hospital services was measured by the number of previous psychiatric hospitalizations and the number of days that each adolescent remained in the hospital for the indexed admission. 4 tables and 43 references