Ripples across generations: offspring outcomes after parental infant institutionalisation, study protocol of the LifeStories Offspring Project

Intergenerational transmission of adversity is increasingly studied, yet little is known about the transmission of specific early-life experiences, particularly deprivation-related experiences. The LifeStories Offspring Project addresses this gap by examining whether infant institutionalisation under conditions of psychosocial deprivation is associated with outcomes in the next generation. The study builds on a population-based, non-selective cohort of individuals placed in Swiss infant care institutions between 1958 and 1961 under social and compulsory measures before the 1981 law reform. The parent generation was first assessed in infancy, followed up in adolescence, and reassessed approximately 60 years later. Compared with a non-institutionalised community cohort from the Zurich Longitudinal Studies, formerly placed individuals showed poorer physical and mental health, poorer cognitive functioning, and increased mortality. The current study will examine the adolescent and adult offspring of formerly institutionalised individuals (N = 163) and compare them with offspring from the non-affected ZLS cohort. Using questionnaires, neuropsychological assessments, and semi-narrative interviews, the study will investigate physical, cognitive, socioemotional, and socioeconomic outcomes, as well as potential pathways of transmission. Quantitative data will be analysed using longitudinal statistical techniques, including latent growth models, latent mediation and moderation models, and random-intercept cross-lagged models. By focusing on adult “children” of individuals exposed to a clearly defined context of early psychosocial deprivation, this globally unique study moves beyond general adversity frameworks and threat-based models of intergenerational transmission. It investigates how the absence of early caregiving experiences may reverberate when those affected become parents themselves, while also contributing to societal recognition and reconciliation related to compulsory social measures in Switzerland.