The present study set out to test Coleman's focal theory of adolescence in a cross-national context. The London Sentence Completion Test (LSCT) and the Louvain Loneliness Scale for Children and Adolescents (LLCA) were administered to 370 adolescents (11 to 17 years of age) in the Dutch-speaking part of Belgium. The findings confirm those of earlier work using the London Sentence Completion Test (LSCT) and other questionnaire-type measures in various English-speaking countries (England, Scotland, New Zealand and United States). The general pattern of peak ages for adolescents' interpersonal concerns provided support for the focal model. Negative feelings about being alone, relationships with parents, heterosexual relationships, small groups and rejection from larger groups do not emerge all at once, but seem to be dealt with issue by issue. The results for the Louvain Loneliness Scale for Children and Adolescents (LLCA), which measures loneliness in relationships with both parents and peers, and adolescents' attitudes towards being alone, confirmed the age trends observed with the sentence completion measure. Taken together, these findings strongly suggest that the changes in adolescent relationships are intimately linked to the general process of individuation, as implied by the focal model. It should be pointed out, however, that important parts of the focal theory remain at present untested. Suggestions for future empirical and conceptual work related to these aspects of Coleman's model are outlined. (C) 1999 The Association for Professionals in Services for Adolescents.