Kandola A, et al. - Researchers investigated if and how depressive symptoms are associated with objectively measured physical activity and sedentary behavior in adolescents. They used regression and group-based trajectory modeling to determine the associations between the physical activity and sedentary behavior variables and depression (CIS-R) scores at age 18 years. Among the 14,901 adolescents whose mothers were invited to participate in the Avon Longitudinal Study of Parents and Children (ALSPAC) study, they identified 4,257 adolescents who had a CIS-R depression score at age 18 years. Observations revealed a negative correlation of moderate-to-vigorous physical activity (per 15 min/day increase) at age 12 years (0·910 [0·857–0·966]) and total physical activity (per 100 CPM increase) at ages 12 years (0·941 [0·910–0·972]) and 14 years (0·965 [0·932–0·999]) with depressive symptoms. Throughout adolescence, sedentary behavior displaces light activity, which is linked with a greater risk of depressive symptoms at 18 years of age. They suggest the possible value of increasing light activity and decreasing sedentary behavior during adolescence as a relevant target for public health interventions directed at decreasing the prevalence of depression.