The key aim of our study was to examine pathways from exposure to childhood adversities (i.e., deprivation and threat) to adolescent psychopathology. The assessed mediating mechanisms included cognitive ability and emotion regulation, as proposed by the Dimensional Model of Adversity and Psychopathology (DMAP). The study comprised participants from the nationally representative Millennium Cohort Study. Latent scores for deprivation and threat were derived using confirmatory factor analysis from indicators collected when participants were at age of 9 months, 3 and 5 years. Cognitive ability was measured using the Verbal Similarities subscale of the British Ability Scales II at age 11, and emotion regulation was measured using emotion dysregulation subscale of the Child Social Behavioural Questionnaire at age 7. Psychopathology, defined as psychological distress, was assessed using the Kessler 6 scale at age 17. We conducted causal mediation analysis adjusting for multiple confounding factors. We did not find total effect of either exposure to deprivation or threat on psychological distress, but we did find significant indirect effects of exposure to deprivation on psychological distress via cognitive ability (- 0.11, 95% CI - 0.20 to - 0.05) and emotion regulation (0.03, 0.02 to 0.12), and exposure to threat on psychological distress via cognitive ability (- 0.04, - 0.07 to - 0.01) and emotion regulation (0.09, 0.03 to 0.15). The lack of associations between deprivation or threat and psychological distress may be due to reporting bias or developmental period of psychopathology. Results of mediation analysis partially support the DMAP but indicate limited benefits to reduce adolescent psychological distress by targeting cognitive ability or emotion regulation to those exposed to childhood adversities.