Hello Darkness, My Old Friend: Moderating a Random Intercept Cross-lagged Panel Model of Loneliness and Symptoms of Anxiety and Depression.

The present study investigated the trait- and state-like associations between loneliness and symptoms of anxiety and depression during three years in middle to late adolescence. The moderating effect of gender and social self-efficacy was examined on the hypothesised model. The sample consisted of 1508 Norwegian upper secondary school students (61% female; mean age at T1 = 16.33; 52.9% high socioeconomic position; 70.6% Norwegian-born). We found 1) strong and positive trait- and state-like associations between loneliness and symptoms of anxiety and depression, 2) that anxiety and depressive symptoms consistently predicted later loneliness but not the other way around, 3) that gender moderated parts of the state-like associations between loneliness and symptoms of anxiety and depression, and 4) that social self-efficacy had no moderating effect on the longitudinal relationship between loneliness and anxiety and depressive symptoms. The present study might inform future research, theory development, and intervention strategies in middle to late adolescent samples.