BackgroundMultiple or persistent crying, sleeping, or feeding problems in early childhood (regulatory problems) are associated with increased internalizing symptoms in adulthood. Unknown is whether early regulatory problems are associated with emotional disorders in adulthood, and what psychosocial factors may provide protection. We tested whether early childhood multiple or persistent regulatory problems are associated with a higher risk of (a) any mood and anxiety disorder in adulthood; (b) perceiving no social support in adulthood; and (c) whether social support provides protection from mood and anxiety disorders among participants who had multiple/persistent regulatory problems and those who never had regulatory problems.MethodsData from two prospective longitudinal studies in Germany (n= 297) and Finland (n= 342) was included (N= 639). Regulatory problems were assessed at 5, 20, and 56 months with the same standardized parental interviews and neurological examinations. In adulthood (24–30 years), emotional disorders were assessed with diagnostic interviews and social support with questionnaires.ResultsChildren with multiple/persistent regulatory problems (n= 132) had a higher risk of any mood disorder (odds ratio (OR) = 1.81 [95% confidence interval = 1.01–3.23]) and of not having any social support from peers and friends (OR = 1.67 [1.07–2.58]) in adulthood than children who never had regulatory problems. Social support from peers and friends provided protection from mood disorders, but only among adults who never had regulatory problems (OR = 4.03 [2.16–7.94];p= .039 for regulatory problems x social support interaction).ConclusionsChildren with multiple/persistent regulatory problems are at increased risk of mood disorders in young adulthood. Social support from peers and friends may, however, only provide protection from mood disorders in individuals who never had regulatory problems.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12888-023-04854-1.