Coronavirus disease (COVID-19) is an infectious disease caused by a new strain of severe acute respiratory syndrome coronavirus, SARS-CoV-2 (1). It first emerged in December 2019 in China and was declared as a global pandemic in March 2020 (2). COVID-19 brings about both physical and mental health complications. Adverse mental health outcomes such as increased stress, higher levels of worry and fatigue, pandemic-related fear and anxiety, depressive, anxiety and post-traumatic stress symptoms have been consistently reported in COVID-19 studies on the general population across different countries (3–7). The indirect effects of COVID-19 such as economic ramification (8) and social isolation (9, 10) due to public health policies further compromise individuals’ psychological well-being. In particular, individuals with pre-existing mental illness constitute one of the vulnerable populations in the pandemic. Literature showed that psychiatric patients had higher rates of COVID-19 infection (11, 12) and mortality (13, 14), and experienced greater psychological distress with more severe depressive and anxiety symptoms, and sleep disturbances (15, 16).

Owing to its high contagious nature, many countries have implemented a myriad of preventive measures in containing COVID-19 infection. In Hong Kong (HK), local infections waxed and waned in an early pandemic stage until an emergence of the Omicron variant in the community in late December 2021. Subsequently, a new wave of outbreak began (Supplementary Figure S1) and the 7-day rolling average of COVID-related deaths reached 3.73 per 1000 people at the peak, the highest worldwide, since Omicron variant was detected (17, 18). It was even estimated that approximately half of the HK population (i.e., 3.6 million) have contracted COVID-19 during the fifth wave by mid-March (19). Epidemiological control measures were further tightened, together with the consideration of implementing compulsory mass COVID-19 testing (and the associated lockdown measures) to the entire population by the government (20). Previous studies reported increased prevalence of depression and anxiety in the general population (21–23), and worsening of mood symptoms in psychiatric patients (24) during the early stage of COVID-19 in HK.

Of note, recent data have found that COVID-19 outbreak and its related psychological distress may be associated with poorer cognitive functioning in the general population (25, 26) and psychiatric patients (27). In particular, psychiatric patients may have already experienced certain extent of cognitive deficits due to their pre-existing mental illness, and may be therefore more susceptible to further cognitive deterioration in the midst of pandemic. Despite the significance of cognitive impairment on psychosocial functioning, there is a paucity of research specifically investigating cognitive complaints in psychiatric patients and its relationship with COVID-19 related factors. To this end, the current study aimed to: firstly, examine the prevalence of subjective cognitive impairment (SCI) in a representative cohort of Chinese patients with common and severe mental disorders during the fifth wave of COVID-19 pandemic in HK; and secondly, to identify correlates of SCI among psychiatric patients by comprehensively evaluating a wide array of factors encompassing socio-demographics, psychopathological symptoms, level of resilience, stress coping strategies and COVID-19 related variables.

The current study aimed to examine the prevalence and correlates of SCI in Chinese psychiatric patients during the fifth wave of COVID-19 in HK. To our knowledge, this is one of the few studies to investigate SCI in psychiatric patients in relation to COVID-19 pandemic, and is the first of its kind in Asia and in Chinese population. Our results showed that almost half of our patient sample reported moderate-to-severe SCI. This is slightly higher than that observed in a recent Spanish study which found that 40.9% of psychiatric patients reported cognitive complaints during COVID-19 lockdown (27).

Our results from a multivariate model 1 on psychopathological symptoms revealed that depressive and PTSD-like symptoms were related to CI+ status. Importantly, these two symptom domains remained significant in the final combined model, indicating that more severe depressive and PTSD-like symptoms were independently associated with moderate-to-severe SCI. In fact, the observed association between depression and CI+ is consistent with a prior Spanish study which demonstrated that psychiatric patients with greater depressive symptom severity were significantly more likely to be categorized in CI+ group (27). It is noteworthy that this Spanish study also found a significant association between CI+ and negative symptoms (as measured by CAPE), which, nonetheless, are greatly overlapped with (and thus likely represent) depressive symptoms (27). There is also ample evidence supporting the link between depression and cognitive impairment. Literature has shown that patients with depression exhibit cognitive dysfunction during an acute phase as well as in remission (48–50). Alternatively, the significant relationship between PTSD-like symptoms and CI+ status corroborates with previous findings suggesting that the pandemic can act as a traumatic stressor, which may compromise individuals’ cognitive functions via the process of maladaptive mind wandering (51). Briefly, maladaptive mind wandering has been put forward as an important pathway mediating the association between PTSD-like symptoms and cognitive impairment by competing for the limited cognitive resources such as working memory capacity (52). In the context of COVID-19, maladaptive mind wandering comprises persistent worries of contagion and other pandemic-related adverse consequences, increased alertness and self-monitoring of physical symptoms, and constant checking of COVID-19 related news, to name a few (51). Taken together, our findings on psychopathological symptoms indicate that early recognition and prompt intervention (e.g., psychological treatments) of depressive and PTSD-like symptoms emerged in the pandemic not only alleviate symptom severity but may also reduce the risk of developing SCI in psychiatric patients.

We have conducted a comprehensive evaluation of coping strategies, resilience and COVID-19 related factors among psychiatric patients. Our multivariate model 2 showed that adoption of avoidant coping style, lower resilience and a greater number of stressors were related to CI+ status. The final model incorporating psychopathological symptoms as well as socio-demographics and illness profiles indicated that avoidant coping style remained significantly associated with CI+. It is acknowledged that avoidant coping is characterized by making cognitive and behavioral efforts in evading traumatic-related stressors (53). An extensive literature has documented the bi-directional association between avoidant coping strategies and various psychopathological symptoms including PTSD symptoms (54, 55), depression and anxiety (56). Recent data have also found that individuals with more frequent use of avoidant coping strategies experienced more depressive and anxiety symptoms during COVID-19 lockdown (57). Given its close relationship with PTSD-like, depressive and anxiety symptoms, avoidant coping style may thus exert an indirect effect on the development of SCI via manifestations of these psychopathological symptoms. Conversely, an earlier Spanish study demonstrated that positive coping strategies including performing physical and relaxing activities, and maintaining a routine during the lockdown were protective factors against cognitive complaints during lockdown, albeit these coping variables became non-significant in their final combined model incorporating psychopathological symptoms (27). Of note, we failed to identify any COVID-19 related factors that were independently associated with CI+. It is possible that the potential effect of COVID-19 related factors on SCI could be fully mediated by psychopathological symptoms and maladaptive coping styles. Owing to the paucity of existing data, further research is required to verify our findings on the relationship between pandemic-related factors and SCI in psychiatric patients.

This study has several methodological limitations. First, although the SCI questionnaire was adapted from COBRA, an established self-report measure of cognitive complaints in psychiatric patients, and has been adopted in a recent study examining SCI in patients with CMD and SMD during pandemic, further research is still needed to verify its psychometric properties. Second, our results were based on patients’ self-perceived cognitive complaints rather than objective cognitive assessment, which was not included in the study. This precludes us from clarifying whether our findings on SCI would be discrepant from data obtained via objective measures. Notably, there is evidence indicating poor concordance between subjective cognitive ratings and objective cognitive performance in healthy participants (58, 59) and psychiatric samples (60, 61). It is postulated that SCI and objectively-measured cognitive functions may represent two relatively distinct, albeit related, constructs. An inherent difference in settings between objective cognitive evaluation using standardized battery conducted in laboratory environment and self-perceived deficits emerged in unstructured real-world situations may also contribute to a lack of concurrence between these two cognitive measures. Third, the cross-sectional study design precludes establishment of causal relationship. Longitudinal research is warranted to determine the course of SCI over time and its predictors. Fourth, we did not collect data regarding the use of pharmacological or psychological treatment, and side-effects of psychotropic medications. Thus, we were not able to assess the potential effect of these treatment modalities on mental health outcomes and cognitive impairment. Lastly, as HK is a highly urbanized city and is categorized by the World Bank as a high-income economy (62), our findings may not be generalizable to mainland China or other Asian regions. Differences in ethno-cultural backgrounds as well as access to and quality of healthcare services across regions may further limit the generalizability of our results to other countries.

In conclusion, our study shows that moderate-to-severe cognitive complaints are prevalent in Chinese psychiatric outpatients during the fifth wave of COVID-19 pandemic. Depressive symptoms, PTSD-like symptoms and avoidant coping style are found to be correlates of CI+ status. Our results have several clinical implications. Although COVID-19 related factors are not independently associated with subjective cognitive impairment, the susceptibility of patients with pre-existing mental illness to COVID-19 related stressors and their ramifications on exacerbation of psychopathological symptoms and the overall psychological wellbeing should not be overlooked. Given the increased vulnerability to exacerbation of pre-existing cognitive dysfunction among psychiatric patients amidst the pandemic (and future public health crisis), early detection and psychosocial interventions of psychopathological symptoms, in particular depressive and PTSD-like symptoms, as well as rectification of maladaptive coping strategies are hence, crucial to minimize negative mental health impact and cognitive impairment. Exploration and development of effective strategies to promote personal resilience and the use of positive coping methods may also enhance protection against elevated risk of cognitive complaints. Prospective follow-up investigation is required to track the longitudinal trajectories of SCI and its predictors in relation to the subsequent course of pandemic and the post-pandemic era as well as the accompanied changes in public health policy measures.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving humans were approved by Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

Wic, EC, and CW designed and conceptualized the study. VF, JaC, JoC, and RC conducted data collection. VF and JaC conducted statistical analysis. VF wrote the first draft of the manuscript. Wic, VF, EC, CW, and CL interpreted the study data. Wic and VF revised and finalized the manuscript. All authors contributed to the article and approved the submitted version.

The study was supported by the Hong Kong Research Grants Council (grant number: 10617014). The funders had no role in study design, data collection, data analysis, interpretation of the data, manuscript preparation or journal submission.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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