Background: In a rapidly changing and increasingly interconnected world, the issue of mental health and well-being among adolescents is one of the important research topics. However, there have been few studies amongst Japanese adolescents that have been published in international journals. Objectives: (I) to make a comparison in selfconcept between healthy adolescents in Japan and Sweden, (II) to address the influence of perceived parental rearing on self-concept and mental health problems among Japanese adolescents, (III) to investigate contributions of attachment and self-concept to mental health problems reported by Japanese adolescents, (IV) to address a comparison of mental health problems and self reported competence in adolescents from Greece, Japan, Russia, and Sweden. Methods: The following self-report instruments were used: Self- Description Questionnaire II (Marsh, 1992), Actual-Ideal Questionnaire (Nishikawa, 2003), Self-Description Questionnaire IIShort (Marsh, Ellis, Parada, Richards, & Heubeck, 2005), Youth Self- Report (Achenbach, 1991), Attachment Questionnaire- for Children (Sharpe et al., 1998), and Egna Minnen Beträffande Uppfostran (my memories of child upbringing) for Children (Muris, Meesters, & van Brakel, 2003). The participants for Paper I were adolescents aged 14 and 15 from Japan (n=144) and Sweden (n=96). One hundred ninety three Japanese students between the ages of 15-19 participated in Paper II and 228 students for Paper III. The participants for Paper IV were 812 healthy adolescents between 15 and 17 years of age from Greece (n=152), Japan (n=219), Russia (n=159), and Sweden (n=282).  Results: Paper I showed that Japanese students reported less positive self-concept compared to the Swedish counterparts. The results were discussed in terms of different response style and modesty in Japanese culture. Paper II showed that dysfunctional parental rearing and insecure peer attachment were associated with negative self-concept and more mental health problems. A unique influence on mental health problems from parent-adolescent relationships depending on the gender of parents and adolescents was also found. Paper III showed a mediating role of self-concept in influencing the relationships between attachment style and Internalizing Problems. Paper IV indicated rather small differences across countries in the syndrome scales. Japanese and Swedish adolescents tended to score lower than Russian and Greek counterparts. Some cultural specific syndromes were found. Conclusion: These results reported in this thesis present a general view of Japanese adolescents’ self-concept and the influence of interpersonal relationships in mental health problems assessed by Western self-report instruments. When being compared with other countries, cultural background and response style must be taken into account.

The main objective of this study was to examine the vulnerability factors of Obsessive Compulsive Symptomatology (OCS) in a non-clinical sample. On the basis of Salkovskis&rsquo / cognitive model of OCD, the present study aimed to investigate the role of perceived parental rearing behaviors, responsibility attitudes, and life events in predicting OCS. Furthermore, the mediator role of responsibility attitudes in the relationship between perceived parental rearing behaviors and OCS was examined. Finally, the specificity of these variables to OCS was evaluated by examining the relationship of the same variables to depression and trait anxiety. Analysis of covariance results showed that subjects with higher OCS scores perceived their mothers&rsquo / and fathers&rsquo / rearing behaviors as more overprotective than the subjects with lower OCS scores. The results of the regression analysis showed that perceived mother overprotection, responsibility attitudes and life events significantly predicted OCS. Furthermore, responsibility attitudes mediated the relationship between perceived mother overprotection and OCS. The predictive role of perceived mother overprotection was found to be OCS specific. On the other hand, for depression, perceived mother rejection and father emotional warmth, and for trait anxiety, perceived mother emotional warmth had significant predictive effects. While responsibility attitudes were found to be a common predictor for OCS and trait anxiety, its mediator role was OCS specific. OCS, depression and trait anxiety were all significantly predicted by life events. The results of the study were discussed within the relevant literature, and limitations of the study, suggestions for future studies, and clinical implications of the findings were presented.