A longitudinal study of healthcare workers' mental health during Western Australia's unique policy response to COVID-19.

Background: Western Australia's response to the COVID-19 pandemic was swift and effective in implementing public health protections and preventing the spread of the virus for the first 2 years. However, healthcare staff continued to be at increased risk of mental health concerns.

Aims: To investigate the longitudinal patterns of post-traumatic stress symptoms (PTSS), depression and anxiety among healthcare workers in Western Australia, and the risk and protective factors associated with changes in status during the first wave.

Method: Participants comprised 183 healthcare staff working at tertiary hospitals and major clinics across Perth, for whom longitudinal data were available. Questionnaire data were collected before Western Australia's first major COVID-19 community wave in early 2022 and following the first wave in late 2022. Online surveys comprised validated measures assessing psychological symptoms, risk and protective factors, and original measures of workplace factors.

Results: Overall rates of PTSS, depression and anxiety remained stable across the two assessment points. However, latent growth models revealed that those with lower PTSS, depression or anxiety symptoms at baseline reported a larger increase in symptoms over time, and those with higher symptoms at baseline had a smaller decline over time, indicating a 'catch-up' effect. Workplace stressors, sleep difficulties and trauma exposure were key risk factors for changes in psychological symptoms from baseline, and workplace and social supports played protective roles.

Conclusions: Improvements in systemic workplace factors are needed to support healthcare workers' mental health during periods of acute stress, even in settings with high levels of emergency preparedness.