The trajectory of mental health problems for UK emerging adults during COVID-19.

Initial COVID-19 restrictions were associated with declining mental health, particularly in UK emerging adults. Prior research has yet to examine changes in mental health in this demographic over the entire course of the three UK national lockdowns. Drawing upon the Understanding Society COVID-19 Survey, this study examined the trajectory of mental health problems for emerging adults (18-29-year-olds) from April 2020-September 2021. Mental health problems were assessed at nine time-points using the General Health Questionnaire. The analytic sample included 1018 participants (304 males, 714 females). Growth curve modelling was used to examine the trajectory of mental health problems and the associated sociodemographic and health covariates. Females and those with fewer household members, lower income, no private garden, and pre-existing mental or physical health diagnoses reported more mental health problems. Gender differences were evident in the rate of change. Females' mental health problems declined from the first lockdown until just after the relaxation of initial restrictive measures (September 2020), increased until April 2021 (constituting lockdowns two and three), and then slightly decreased until September 2021 during the phased exit from restrictions. Males' mental health problems followed a similar trajectory, with a greater rate of increase in mental health problems from July 2020-April 2021, and a greater rate of decline from April-September 2021. Females reported more mental health problems throughout the three national lockdowns than males. These findings can inform public health policies targeted toward young adult populations and highlight sub-populations at greater risk of worsening mental health.