CONCLUSION: The symptoms of hostility, impulsivity, anxiety, and depression are included in the DSM-IV definition of Postconcussional Disorder. Impulsivity, anxiety, and depression were modestly, but not significantly, increased in those with history of grade III concussion. A significant association between hostility and concussion was found. As with other studies of brain injury in adolescents, the direction of the relationship between hostility and brain injury is unclear. However, the effect brain injury may have on the skills necessary to exit street life may be serious, and should be further investigated.