Testing an integrated model of population mental health: study protocol for the epidemiological, two-arm Mannheim...

Monitoring of population mental health is now considered to play a vital role in health, risk factor and demographic surveillance systems across the globe. Adopting a public mental health perspective on monitoring and surveillance requires us to consider the entire spectrum of mental health, which broadly ranges from positive mental health and well-being to severe mental disorders, including at-risk populations. This population mental health approach has become the mainstay of public mental health provision in many European countries but there is a dearth of research on this issue in Germany in the past 20 years and fundamental conceptual and methodological issues remain to be addressed at both the national and international levels.

The Mannheim incidence and inception cohort study is a recently established two-arm population-based incidence (arm 1) and inception cohort (arm 2) study in the catchment area of Mannheim, Germany. In the incidence-arm, case ascertainment of incident cases is carried out for the years of 2024 and 2025 based on clinical assessment via structured clinical interviews and retrospective case record evaluation. In the inception cohort arm, we recruit and follow an epidemiologically characterised population-based cohort of individuals (1) without symptoms (ie, stage 0), (2) meeting the criteria for non-specific psychological distress (ie, stage 1 a) or (3) a Clinical High At-Risk Mental State for severe mental disorder (ie, stage 1b) at baseline and up to four follow-up assessments every 6 months. Assessments include clinical interviews, self-report measures and ecological momentary assessment.Poisson regression will be conducted to quantify variation in incident rates by age, sex and migrant/ethnic minority group status. In the inception cohort arm, we will perform maximum likelihood estimation of hazard rates to estimate rates of transition from earlier stages to later stages. Latent class analysis will be used to identify empirically-based clinical stages to test convergence with contemporary staging models.

The study has received ethical approval from the local ethics committee (Medical Faculty Mannheim, Heidelberg University, 585-21). Results will be published in peer-reviewed journals, presented at academic conferences and disseminated through (social) media to address a broader public audience.