Anxiety among Adolescents : Measurement, Clinical Characteristics, and Influences of Parenting and Genetics

Anxiety is the most commonly reported mental health problem among adolescents. Still, many adolescents in need of treatment are not detected and the clinical characteristics and etiological pathways of adolescent anxiety are under-researched topics. This thesis examined the clinical utility of the Swedish versions of the Spence Children’s Anxiety Scale (SCAS) and the clinical characteristics of multiple anxiety disorders among psychiatrically referred adolescents, and the influence of parenting and oxytocin gene (OXT) variants on anxiety among adolescents in the general population. Studies employed cross-sectional and longitudinal designs and were based on questionnaire, interview, and genotype data. Support for the reliability and validity of both SCAS and SCAS-P was obtained. The overall ability to predict anxiety among referred adolescents ranged from fair to excellent for both scales. Among adolescents psychiatrically referred for any reason, the prevalence of any anxiety disorder was 46%. Homotypic comorbidity was observed in 43%, and heterotypic comorbidity in 91%. Early adolescent anxiety influenced homotypic anxiety in late adolescence independent of parental rejection and control. The mediating role of parenting was small with indirect effect sizes no larger than one-tenth the size of direct effects, irrespective of the informant on parenting behavior. Significant interaction effects with positive and negative parenting were observed for OXT variants rs4813625 and rs2770378 in relation to social anxiety. The nature of the interactions was in line with the differential susceptibility framework for rs4813625, whereas for rs2770378, results indicated a diathesis–stress type of interaction. The findings suggest that psychiatrically referred adolescents with anxiety disorders are best characterized as a highly complex patient group and call attention to the necessity of structured assessment. For this purpose, this thesis provides evidence for the clinical utility of the SCAS; routine utilization of this questionnaire can improve detection of adolescents in need of anxiety treatment. Findings of this theses further suggest that the influence of positive and negative parenting behaviors on anxiety may be of greater importance among some adolescents than others, depending on individual differences in sensitivity to parenting. The etiology of anxiety among adolescents may therefore involve differential susceptibility effects of the interplay between genes and parenting behaviors