Background and objective:
Despite the contribution to SARS-CoV-2 dissemination control, lockdown measures severely affected the population’s well-being. Previous cross-sectional studies described the prevalence of anxiety and depression symptoms during the pandemic, but longitudinal approaches are needed to understand the impact of implementation and lifting lockdown measures in populations’ well-being. With that purpose, we aimed to assess the impact of lifting lockdown policies in the mental health of the Portuguese population through the COVID-19 pandemic, among different socioeconomic strata.

Methods:
We used the Diaries of a Pandemic database – a longitudinal, web-based, and self-administered questionnaire implemented in Portugal in 2020 and 2021. Using data from the weekly reports of fear, sleep disorders, and negative feelings, we performed an interrupted time series analysis using weekly-aggregated data and a longitudinal analysis using individual data. We further compared the effects across different income, education, and caregiver status.

Results:
We observed negative trends in the proportions of negative feelings [b2020=-1.02, 95%CI2020=(-1.40;-0.64); b2021=-1.12 95%CI2021=(-1.55;-0.69)], sleep disorders [b2020=-3.65, 95%CI2020=(-4.70;-2.61); b2021=-0.87 95%CI2021=(-1.25;-0.49)], and feelings of fear [b2020=-3.65, 95%CI2020=(-4.70;-2.61); b2021=-0.53 95%CI2021=(-0.78;-0.29)], during both lockdowns, and a statistically significant short-term reduction in the risk of negative feelings in 2020 ([b2020=-6.32, 95%CI2020=(-8.33;-4.30)], sleep disorders [b2021=-4.35, 95%CI2021=(-8.10;-0.60)], and feelings of fear in 2021 [b2021=-3.25, 95%CI2021=(-5.47;-1.03). Trends became stable after restrictions’ lifting in both waves. Results from the individual-data longitudinal analysis reflected those from the interrupted time series analysis with aggregated data, except for reports of fear, where a statistically significant increase after lockdown was observed in 2020. Regarding socioeconomic factors, although most favoured groups had lower proportions of symptoms, trends were overall similar to those observed in the non-stratified sample.

Conclusion:
Mental health symptoms became less frequent during the 2020 and 2021 COVID-19 waves and its frequency was affected by the lifting of lockdown measures, globally and across socioeconomic groups.