Estonian National Mental Health Study: Design and methods for a registry-linked longitudinal survey.

Objectives: The Estonian National Mental Health Study (EMHS) was conducted in 2021-2022 to provide population-wide data on mental health in the context of COVID-19 pandemic. The main objective of this paper is to describe the rationale, design, and methods of the EMHS and to evaluate the survey response.

Methods: Regionally representative stratified random sample of 20,000 persons aged 15 years and older was drawn from the Estonian Population Register for the study.