Parental support buffers the association of depressive symptoms with cortisol and C-reactive protein during adolescence

•Depressive symptoms have been linked with inflammatory processes.•Parental support modified this association during adolescence.•Depressive symptoms correlated with CRP for those with low parental support.•The association was non-significant for those with high parental support.•Friend support did not modify the association.

Social experiences can affect the relationship between depression and physical health. The current study examined how social support from parents and friends may moderate the association of depressive symptoms with hypothalamic-pituitary-adrenal (HPA) axis activity and C-reactive protein among adolescents (N = 316, Mage = 16.40, SD = .74; 57% female) from diverse ethnic backgrounds (23.1% Asian, 29.1% European, 41.8% Latino, and 6.0% other backgrounds). Results indicated that parent support, but not friend support, moderated the link between depressive symptoms and both total daily cortisol output (a measure HPA activity) and C-reactive protein (a marker of inflammation). These patterns did not differ by ethnicity. Overall, the study highlights the continued, and perhaps accumulated, importance of parents during adolescence despite increasing needs for autonomy from and exploration outside of the family unit.