BackgroundPsychiatric disorder diagnoses are linked to long-term socioeconomic ‘shadows’ into adulthood, but little is known about how these diagnoses are associated with adulthood payment problems in Norway and whether these associations are moderated by parental and area characteristics.MethodsWe combine Norwegian registry data with payment problem records from the public debt enforcement agency for the 1995–1997 birth cohorts (n=173 750). We ascertain behavioural, neurotic, mood and substance use disorder diagnoses from specialised care at ages 13–17. Payment problems are defined as any records of mandatory deductions in wages or benefits up to age 23. Causal forests are used to explore the potential moderating role of sociodemographic variables.ResultsSome 6% of the sample have payment problems, but the share is higher among men and among people with low childhood socioeconomic status. After adjusting for background characteristics, behavioural problem diagnoses are linked to a 4.6 percentage point higher risk of payment problems (95% CI 4.1 to 5), mood disorder diagnoses to a 2.2 percentage point higher risk (95% CI 1.5 to 2.9), neurotic disorder diagnoses to a 2.5 percentage point higher risk (95% CI 2 to 3.1) and substance use disorder diagnoses to a 9.3 percentage point higher risk (95% CI 7.6 to 10.9). The associations between substance use and behavioural diagnoses and payment problems are stronger for people with low childhood socioeconomic status.ConclusionThe associations between adolescent substance and behavioural diagnoses and adulthood payment problems are particularly strong among people with low childhood socioeconomic status. Reducing these associations is critical for preventing the accumulation of disadvantages.