Background: Governments have implemented a range of measure to tackle COVID-19, primarily focusing on changing citizens' behaviours in order to lower transmission of the virus. Some policymakers have expressed concern that citizens would not maintain high levels of compliance with these behaviours over the pandemic and would instead exhibit so-called "behavioural fatigue". While the concept has been criticized, there have been few tests of behavioural fatigue using data from the COVID-19 pandemic, and none that have tracked individuals' compliance trajectories. Methods: We used longitudinal data on self-reported compliance from 50,851 adults in the COVID-19 Social Study collected across two waves of the pandemic in the UK (01 April 2020 - 22 February 2021). We modelled typical compliance trajectories using latent growth curve analysis (LGCA) and tested for behavioural fatigue by attempting to identify a set of participants whose compliance decreased substantially over the study period. Results: We selected a four-class LGCA solution. Most individuals maintained high levels of compliance over the pandemic and reported similar levels of compliance across the first and second waves. Approximately one in seven participants had decreasing levels of compliance across the pandemic, reporting noticeably lower levels of compliance in the second wave, a pattern compatible with behavioural fatigue. Individuals with declining compliance levels differed from those with consistently high compliance on multiple characteristics, including (young) age, better physical health, lower empathy and conscientiousness and greater general willingness to take risks. Conclusion: While a minority, not all individuals have maintained high compliance across the pandemic. Decreasing compliance is related to several psychological traits. The results suggest that targeting of behaviour change messages later in the pandemic may be needed to increase compliance.
Trajectories of compliance with COVID-19 related guidelines: longitudinal analyses of 50,000 UK adults