A teen dating partner can prove to be abusive rather than affectionate as a way to assert power in a relationship, a U.S. psychologist said. Sherry L. Hamby -- a research associate professor at Sewanee, the University of the South in Tennessee, and a research associate with the University of New Hampshire Crimes against Children Research Center -- said teens who use violence and those who are vulnerable to being victimized have typically experienced previous victimization, harsh parenting and other adversities. Some of the most dangerous youth are those who expect their dates to meet all of their emotional and social needs, Hamby said. Warning signs include jealousy -- and jealousy that is way out of proportion to how long a couple have been dating, or how serious their relationship, is a big warning sign. So are controlling and monitoring behaviors. "If you have to send your boyfriend a picture from your phone to prove that you are really at your grandmother's house, that's a problem," Hamby said in a statement. "Youth who turn to violence to solve other problems are also at increased risk of perpetrating teen dating violence." Hamby, editor of the American Psychological Association's journal Psychology of Violence, said the journal was releasing a special issue about the interconnections among different types of violence. Teens, parents or anyone else -- regardless of where they live in the United States -- can call the National Domestic Violence Hotline at 1-800-799-SAFE or loveisrespect at 1-866-331-9474, or text "loveis" to 77054.