Childhood maltreatment is common and associated with a wide range of adverse outcomes, yet few large, well-designed longitudinal studies follow children and adolescents with substantiated maltreatment over time. The Norwegian Triple-S Cohort Study was established to recruit and follow children and adolescents, together with their non-offending caregiver, to identify key risk and resilience factors and understand long-term health and functioning.

The cohort invites children and adolescents aged 5–18 years with substantiated maltreatment, including physical abuse, emotional abuse, sexual abuse, neglect or exposure to domestic violence. Participants attend the Stine Sofie Centre, a national learning and coping centre for families affected by maltreatment in Norway. At intake, both the child/adolescent and the non-offending caregiver are invited to participate. Participants are followed at regular intervals after enrolment, typically at 2-year intervals, and, with consent, survey data can be linked to national health, education, employment and social welfare registries. As of June 2026, 733 caregivers and 325 adolescents aged 12–18 years had completed baseline questionnaires. Recruitment is ongoing and will continue until the cohort reaches approximately 1500 participating children and adolescents.

Data collection includes information on children and adolescents’ maltreatment type, mental and somatic health, behavioural and neurodevelopmental symptoms, self-harm and suicidality, sleep, social relationships, school functioning, health behaviours and service use. Caregiver data cover mental and physical health, self-harm and suicidality, interpersonal victimisation across the life course, socioeconomic and lifestyle factors, parenting practices, family dynamics and relationship quality and perceived service needs. Published analyses have documented substantial mental health and sleep difficulties, impaired school functioning and high levels of non-suicidal self-harm among children and adolescents exposed to maltreatment. Other studies have shown considerable variation in service use and coordination, and that emotional, relational and practical barriers may hinder disclosure. Analyses of caregiver data have also highlighted both relational strengths and areas of difficulty in parenting, as well as socioeconomic vulnerability among mothers with cumulative exposure to interpersonal violence across childhood and adulthood.

Continued follow-up will enable detailed investigation of long-term outcomes after substantiated childhood maltreatment, including trajectories of mental health, education, work participation and service use. The cohort will be used to identify key risk and protective factors, including intergenerational patterns of adversity and resilience. Planned linkages to national registries will provide comprehensive life-course data, and additional data collection within the cohort through qualitative interviews is intended to offer deeper insight into the lived experiences of children and caregivers. Findings will inform prevention efforts and contribute to improved service delivery and coordination for maltreated children and their families.