In a recent study published within the journal Scientific Reports, researchers examined the results of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination on insomnia, depression, and anxiety.

The coronavirus disease 2019 (COVID-19) pandemic has unprecedentedly impacted society. Evidence suggests increased rates of psychiatric disorders through the pandemic. Further, studies have observed a reduced prevalence of tension and depressive symptoms amongst people vaccinated for COVID-19 in comparison with non-vaccinated individuals in the US (US).

Likewise, one other study revealed that the prevalence of those symptoms declined after vaccination in Bangladesh. Although over 3.5 billion vaccine doses have been administered in China until April 2023, data on the results of vaccination on mental health outcomes are limited.

Study: SARS-CoV-2 vaccination may improve anxious, insomnia and depressive symptoms amongst Chinese population aged 18–75 years through the COVID-19 pandemic. Image Credit: aslysun / Shutterstock

Concerning the study

The current study investigated whether COVID-19 vaccination could mitigate insomnia, anxiety, and depressive symptoms through the pandemic. Chinese adults aged 18–75 who could complete online questionnaires were recruited. Individuals with psychiatric diseases or incomplete data were excluded.

The team developed an ordinary questionnaire for demographics and socioeconomic indicators. The seven-item generalized anxiety disorder (GAD-7) assessment was used to look at anxiety symptoms. GAD-7 scores 1–4, 5–9, 10–14, and 15–21 indicated minimal, mild, moderate, and severe symptoms, respectively.

A GAD-7 rating ≥ 5 was deemed the critical value for anxiety. The Athens Insomnia Scale (AIS)-8 was used to evaluate symptoms of insomnia. AIS-8 scores ranged between 0 and 24. The AIS-8 rating of six points was deemed critical for diagnosing insomnia with clinical significance. The patient health questionnaire (PHQ-9) was used to guage depressive symptoms.

PHQ-9 scores ranged between 0 and 27, with higher scores indicating more severe depression. A PHQ-9 rating ≥ 5 indicated clinical depressive disorder. The researchers used the hierarchical regression method to look at the results of vaccination on insomnia, depression, and anxiety symptoms.

Flowchart of the sample selection.

Findings

In total, 9,452 individuals, aged 35.97 on average, were included. Of those, 76.2% were vaccinated, while the rest were non-vaccinated. Over 71% of participants were urban residents, 68.5% were married, and 85% had a monthly income ≤ 10,000 RMB. Overall, 17.7% of respondents had symptoms of tension, 22.7% had symptoms of insomnia, and 28.4% showed depressive symptoms.

The median PHQ-9, GAD-7, and AIS-8 scores of non-vaccinated individuals were 6, 3, and 4 points, respectively, and were considerably higher than for vaccinated individuals. The COVID-19 vaccination significantly decreased the prevalence of severe symptoms of tension or depression. Anxiety prevalence (9.7%) within the vaccinated group was substantially lower than within the non-vaccinated group (43.7%).

Furthermore, individuals with anxiety were younger than those without. Likewise, the prevalence of insomnia was lower within the vaccinated group (16.2%) in comparison with non-vaccinated individuals (43.7%). Further, insomnia prevalence in individuals with anxiety was 63.3% in comparison with 4.3% amongst those without anxiety. Besides, depressive symptoms were less prevalent amongst vaccinated individuals (19.7%) than within the non-vaccinated group (56.1%).

The prevalence of depressive symptoms was significantly higher amongst individuals with insomnia (81.7%) or anxiety (93.4%) in comparison with those without insomnia or anxiety. The researchers noted a big association between the COVID-19 vaccination and anxiety symptoms. That’s, the vaccinated group had about 85% lower anxiety risk than the non-vaccinated group, adjusted for potential confounders (age, sex, marital status, income, education, and occupation).

Further, vaccinated individuals had a 74.9% lower risk of insomnia than non-vaccinated participants, adjusted for confounders. When moreover adjusted for anxiety symptoms, the vaccinated group had 40% lower odds of insomnia in comparison with the non-vaccinated group. Besides, vaccinated participants also had about 80% lower risk of depression than non-vaccinated subjects—this association was sustained after moreover adjusting for anxiety or insomnia.

Conclusions

To summarize, the researchers investigated whether COVID-19 vaccination has a positive impact on symptoms of depression, anxiety, and insomnia through the pandemic. Vaccinated individuals showed significantly lower scores on the PHQ-9, AIS-8, and GAD-7 scales than non-vaccinated individuals. Furthermore, vaccination was related to a reduced risk of depressive, anxiety, and insomnia symptoms.

The study’s limitations include its non-generalizability to other populations, including minors and elderly individuals. Furthermore, the self-reported nature of the study can have introduced some level of (reporting) bias. Besides, the numerous difference in size between the vaccinated and non-vaccinated groups might reduce statistical power. Taken together, the findings illustrate that the COVID-19 vaccination may help alleviate anxiety, insomnia, and depression.