Original ArticlesPsychometric Properties of the Defense Style Questionnaire (DSQ-40) in AdolescentsRuuttu, Titta MA(Psych)*†‡; Pelkonen, Mirjami PhD*†; Holi, Matti MD, PhD*§; Karlsson, Linnea MD, PhD*∥; Kiviruusu, Olli BSocSc*; Heilä, Hannele MD, PhD*; Tuisku, Virpi MSocSc*; Tuulio-Henriksson, Annamari LicPhil*; Marttunen, Mauri MD, PhD*†¶ Author Information *Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland; †Department of Adolescent Psychiatry, Peijas Hospital, Hospital District of University of Helsinki, Vantaa, Finland; ‡Department of Psychology, University of Helsinki, Helsinki, Finland; §Department of Psychiatry, Helsinki University Central Hospital, Helsinki, Finland; ∥Department of Psychiatry, Turku University Central Hospital, Turku, Finland; and ¶Department of Psychiatry, University of Kuopio, Kuopio, Finland. Send reprint requests to Titta Ruuttu, National Public Health Institute, Department of Mental Health and Alcohol Research, Mannerheimintie 166, FIN-00300 Helsinki, Finland. The Journal of Nervous and Mental Disease: February 2006 - Volume 194 - Issue 2 - p 98-105 doi: 10.1097/01.nmd.0000198141.88926.2e Buy Metrics Abstract This study examined the psychometric properties of the Defense Style Questionnaire (DSQ-40) in adolescents. Internal consistency, factor structure, and discriminant and concurrent validity of the DSQ-40 were studied in 211 adolescent psychiatric outpatients aged 13 to 19 years and 199 age-matched and sex-matched controls. Principal components analysis yielded four internally consistent components: mature, neurotic, image-distorting, and immature defense styles. The outpatients reported more immature, image-distorting, and neurotic styles and less mature style than did the controls, suggesting adequate discriminant validity. As a demonstration of convergent and concurrent validity, the severity of psychiatric symptoms assessed by the General Health Questionnaire and psychosocial adjustment assessed by the Global Assessment of Functioning Scale correlated theoretically meaningfully with the different defense styles. The DSQ-40 appears to be a reliable and valid instrument for adolescents. © 2006 Lippincott Williams & Wilkins, Inc.