Introduction Childhood trauma has been suggested to be involved in susceptibility to bipolar disorder (BP). However, it remains unclear whether the occurrence of childhood trauma is differently distributed in subthreshold bipolar disorder (SBP). Objective To assess childhood trauma in young adults with SBP, as compared to young adults with BP and population controls (PC). Method This was a cross-sectional, population-based study. The Mini International Neuropsychiatric Interview (MINI) was used to define the groups with BP (subjects with a lifetime or current manic episode or lifetime or current hypomania with a history of a depressive episode), SBP (subjects with a history of hypomanic episode without lifetime or current depressive episode), and subjects without mood disorders (PC). Childhood trauma was assessed using de Childhood Trauma Questionnaire (CTQ). We investigated differences regarding childhood trauma across the three groups (BP, SBP and PC). Result Except for sexual abuse, all subtypes of childhood trauma remained associated with the BP group as compared to PC. Additionally, when we compared SBP and BP, significant differences were found only for emotional abuse. No significant differences were found in relation to childhood trauma between the SBP and PC groups after adjusting for confounding factors. Conclusion These findings suggest that investigating childhood trauma, with a particular focus on emotional abuse, could be considered a preventive measure and potentially improve the prognosis.