“…Adolescents with co-occurring externalizing and internalizing problems comprise a highly vulnerable group being at extreme risk of demonstrating problems in various life domains, including school failure, violent behaviour, and adult psychiatric illness (Capaldi, 1992;Capaldi & Stoolmiller, 1999;McCarty, Stoep, Kuo, & McCauley, 2006). In addition, co-occurring problems may be related to poorer treatment success (Newman, Moffitt, Caspi, & Silva, 1998;Ollendick, Jarrett, Grills-Taquechel, Hovey, & Wolff, 2008).…”