['Earlier studies suggest that social phobia (SP) and depression (DEP) often have their onset in adolescence, and are highly comorbid, with SP mainly preceding depression. There is a lack of population-based prospective studies among adolescents vulnerable to both disorders, taking into account possible gender differences in the relationship between the two.', 'This study is part of a prospective Adolescent Mental Health Cohort (AMHC) study. Subjects are 9th grade pupils (mean age 15.5 years (sd 0.39)) responding to a survey conducted 2002-2003 (T1) and a 2-year follow-up 2004-2005 (T2) (N=2038). Social phobia was measured by the Social Phobia Inventory (SPIN) and depression by the 13-item Beck Depression Inventory (BDI-13).', 'Risk for depression at T2 by SP at T1 was elevated only among boys (OR 3.6, 95% C.I. 1.507-8.579, p=0.004), whereas among girls, risk for SP at T2 by DEP at T1 was elevated (OR 7.8, 95% CI 4.529-13.391, p<0.001). The course of both disorders was unstable and recovery was common.'] Does relationship between social phobia and depression differ between boys and girls in mid-adolescence?