Our aim is to harmonise existing mental health measures over the life course in UK based birth cohorts. In childhood we will focus on measures of internalising and externalising symptoms as available in all studies, while in adulthood we will focus on measures of common mental disorder (depression and anxiety symptoms. The harmonised measures will allow us to investigate and compare the evolution of common mental disorder over the life course in different generations, as well as test whether mental health is improving or declining in more recently born cohorts that are expected to live longer. At the second stage of the project we will build on the existing harmonised from a previous CLOSER work packages on social class and income data to investigate mental health inequalities in different generations.