Response

We would like to thank Andrea Raballo, Michele Poletti and Antonio Preti for their perceptive commentary on our recent article, which underscores the value of assessing childhood trauma as a transdiagnostic risk factor for future psychopathology in young people. ^{Reference Raballo, Poletti and Preti1}

Our study, Prevalence and risk of psychiatric disorders in young people: prospective cohort study exploring the role of childhood trauma (the HUNT study), is inherently epidemiological, providing a comprehensive overview of the prevalence of exposure to potentially traumatic events in young people, and its relation to later onset of psychiatric disorders. The pathogenicity of (poly)victimisation observed, and measured as a sum score of self-reported exposure to different types of interpersonal violence, may well, as the authors point out, partly relate to the clustering of violence, neglect and other childhood adversity, that presents within families where violence occurs. ^{Reference Kessler, McLaughlin, Green, Gruber, Sampson and Zaslavsky2}

We also want to acknowledge that there are likely several pathways that lead young people to become exposed to multiple potentially traumatic events. In particular, it is crucial not to underestimate the impact of the wider community, including peer violence in the form of bullying, physical violence and sexual abuse, that often go unnoticed and can co-occur. ^{Reference Ranney, Patena, Nugent, Spirito, Boyer and Zatzick3–Reference Korkmaz, Överlien and Lagerlöf4} Moreover, in young people who are predisposed to develop externalising disorders, the associations between exposure and psychopathology appear to be more reciprocal. ^{Reference Carliner, Gary, McLaughlin and Keyes5} We would like to stress that even single traumatic events can have profound ramifications for young people as well. ^{Reference Dyb, Jensen, Nygaard, Ekeberg, Diseths and Wentzel-Larsen6} These studies show that interpersonal violence taking place outside of family relations, individual predispositions and exposure to single events contribute to considerable health problems in young people.

We agree with the authors that assessing childhood trauma is essential – yet also challenging. This is particularly true for experiences that occur in early childhood. Sadly, it is likely that those exposed to violence early in life are also exposed later, at an age when they are old enough to remember and report these events. In our study, the participants were between 12 and 20 years old when reporting about their experiences. However, whether they choose to disclose trauma experiences in the context of a school-based survey remains a personal and sensitive matter.

Disclosure of past experiences is per definition a retrospective activity, affected by contextual factors, as well as past and current experiences, and overall health. Findings from previous research indicate that adults’ reports of childhood trauma may differ depending on the respondents’ level of current health problems. ^{Reference Coleman, Baldwin, Dalgleish, Rose‐Clarke, Widom and Danese7} This indicates that school-based assessments measured in adolescence, and oftentimes prior to the onset of long-term adverse health problems, may be more valid. Nonetheless, previous research has shown that underreporting of trauma is common, which in our study would most likely lead to underestimation of the true impact of trauma exposure on risk for psychiatric disorders. ^{Reference Manay and Collin-Vézina8} Another factor pointing in the same direction is that adolescents with severe post-traumatic psychiatric conditions and related functional impairments are less likely to attend school, and therefore may not have the opportunity to participate in school-based surveys, meaning that some of the most affected voices go unheard. ^{Reference Rangul, Holmen, Langhammer, Ingul, Pape and Fenstad9} Although the HUNT study is known for its exceptionally high participation rate, this limitation also applies to the current study, where 78.4% of eligible participants took part.

Taken together, clinicians and researchers need to have a keen eye when working with young people whose trauma experiences are often well hidden, both within and outside their families. Young people who are exposed to persistent and severe childhood trauma from an early age, furthermore, constitute a particularly vulnerable subgroup of trauma-exposed individuals. Given the barriers that exist in detecting this subgroup and ensuring that they get access to appropriate care from an early stage, we support the authors’ suggestion to explore how supporting families, and targeting parenting as an early modifiable risk factor, can promote healthy development and prevent interpersonal violence and trauma-related developmental derailment. However, other pathways that may lead young people to encounter significant trauma, including community and peer violence, individual predispositions and mass violence events, should not be overlooked as they can have equally detrimental effects on their future mental health.