Although several studies have documented the impact of the COVID-19 pandemic on mental health, the long-term effects remain unclear.

To examine longitudinal changes in mental health before and during the consecutive COVID-19 waves in a well-established probability sample.

An online survey was completed by the participants of the COVID-19 add-on study at four time points: pre-COVID-19 period (2014–2015, n = 1823), first COVID-19 wave (April to May 2020, n = 788), second COVID-19 wave (August to October 2020, n = 532) and third COVID-19 wave (March to April 2021, n = 383). Data were collected via a set of validated instruments, and analysed with latent growth models.

During the pandemic, we observed a significant increase in stress levels (standardised β = 0.473, P < 0.001) and depressive symptoms (standardised β = 1.284, P < 0.001). The rate of increase in depressive symptoms (std. covariance = 0.784, P = 0.014), but not in stress levels (std. covariance = 0.057, P = 0.743), was associated with the pre-pandemic mental health status of the participants. Further analysis showed that secondary stressors played a predominant role in the increase in mental health difficulties. The main secondary stressors were loneliness, negative emotionality associated with the perception of COVID-19 disease, lack of resilience, female gender and younger age.

The surge in stress levels and depressive symptoms persisted across all three consecutive COVID-19 waves. This persistence is attributable to the effects of secondary stressors, and particularly to the status of mental health before the COVID-19 pandemic. Our findings reveal mechanisms underlying the surge in mental health difficulties during the COVID-19 waves, with direct implications for strategies promoting mental health during pandemics.

There is conflicting research regarding the extent to which patient care is a source of stress for emergency medical technicians (EMTs). Some research indicates that it is important, whereas other studies suggest that it takes a “back seat” to administrative and organizational problems. This study sought to explore this issue further by investigating the relationship between caring for patients, daily workday stress, and daily nonworkday stress among EMTs.

All EMTs employed by East Baton Rouge Parish Emergency Medical Services were eligible for participation. After the study was described, subjects completed a demographic information sheet and informed consent was obtained. Participants then completed 30 days of monitoring with a standardized measure of daily stress (the Daily Stress Inventory) and a measure of patient-care stress designed for use in this study (Emergency Call Questionnaire).

A very large portion of the variance in the EMTs' overall daily workday stress was associated with patient care (r = 0.677, p <0.001). Additionally, patient care stress on workdays significantly predicted overall daily stress on the following nonworkday (i.e., post-workday) (r = 0.633, p <0.001). Finally, EMTs who had stressful pre-workdays rated their patient care as more stressful on the following workday (r = 0.512, p <0.01).

Results suggest that patient care is a critical factor in daily stress among EMTs, both on workdays and post-workdays, providing preliminary evidence for a carryover effect. Evidence also suggests that stress on the day before work may influence EMTs' perceptions of their patients on workdays.