Background COVID-19-related information on social media is overabundant and sometimes questionable, resulting in an “infodemic” during the pandemic. While previous studies suggest social media usage increases the risk of developing anxiety symptoms, how induced anxiety affects attitudes and behaviors is less discussed, let alone during a global pandemic. Little is known about the relationship between older adults using social media during a pandemic and their anxiety, their attitudes toward social trust in information, and behaviors to avoid contracting COVID-19. Objective The goal of this study was to investigate the associations between using social media for COVID-19-related information and anxiety symptoms as well as the mediation effect of anxiety symptoms on social trust in information and COVID-safe behaviors among older adults. Methods A cross-sectional telephone survey was conducted in Hong Kong between May and August 2020. A rapid warm-call protocol was developed to train social workers and volunteers from participant nongovernmental organizations to conduct the telephone surveys. Questions related to COVID-safe behaviors, social trust in information, social media use, anxiety and depressive symptoms, and sociodemographic information were asked. The number of confirmed COVID-19 cases at the community level was used to account for the risk of contracting COVID-19. Ordinary least squares regressions examined the associations between social media use and anxiety symptoms, and how they were associated with social trust in information and COVID-safe behaviors. Structural equation modeling further mapped out these relationships to identify the mediation effects of anxiety symptoms. Results This study collected information regarding 3421 adults aged 60 years and older. Use of social media for COVID-19-related information was associated with more anxiety symptoms and lower social trust in information but had no significant relationship with COVID-safe behaviors. Anxiety symptoms predicted lower social trust in information and higher COVID-safe behaviors. Lower social trust in information was predicted by using social media for COVID-19 information, mediated by anxiety symptoms, while no mediation effect was found for COVID-safe behaviors. Conclusions Older adults who rely on social media for COVID-19-related information exhibited more anxiety symptoms, while showing mixed effects on attitudes and behaviors. Social trust in information may be challenged by unverified and contradictory information online. The negligible impact on COVID-safe behaviors suggested that social media may have caused more confusion than consolidating a consistent effort against the pandemic. Media literacy education is recommended to promote critical evaluation of COVID-19-related information and responsible sharing among older adults.

ObjectiveLoneliness is a significant and independent risk factor for depression in later life. Particularly in Asian culture, older people may find it less stigmatising to express loneliness than depression. This study aimed to adapt a simple loneliness screen for use in older Chinese, and to ascertain its relevance in detecting depressive symptoms as a community screening tool.Design, setting and participantsThis cross-sectional study was conducted among 1653 older adults aged 60 years or above living in the community in Hong Kong. This was a convenient sample recruited from four local non-governmental organisations providing community eldercare or mental healthcare services. All data was collected by trained social workers through face-to-face interviews.MeasuresLoneliness was measured using an adapted Chinese version of UCLA 3-item Loneliness Scale, depression symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9), and social support with emotional and instrumental support proxies (number of people who can offer help). Basic demographics including age, gender, education and living arrangement were also recorded.ResultsThe average loneliness score was 3.9±3.0, and it had a moderate correlation with depressive symptoms (r=0.41, p<0.01). A loneliness score of 3 can distinguish those without depression from those with mild or more significant depressive symptoms, defined as a PHQ-9 score of ≥5 (sensitivity 76%, specificity 62%, area under the curve=0.73±0.01). Loneliness explained 18% unique variance of depressive symptoms, adding to age, living arrangement and emotional support as significant predictors.ConclusionA 3-item loneliness scale can reasonably identify older Chinese who are experiencing depressive symptoms as a quick community screening tool. Its wider use may facilitate early detection of depression, especially in cultures with strong mental health stigma.Trial registration numberClinicalTrials.gov NCT03593889

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Expertise in Chinese character recognition is marked by reduced holistic processing (HP), which depends mainly on writing rather than reading experience. Here we show that, while simplified and traditional Chinese readers demonstrated a similar level of HP when processing characters shared between the simplified and traditional scripts, simplified Chinese readers were less holistic than traditional Chinese readers in perceiving simplified characters; this effect depended mainly on their writing rather than reading performance. However, the two groups did not differ in HP of traditional characters, regardless of their difference in reading and writing performances. Our image analysis showed high visual similarity between the two character types, with a larger variance among simplified characters; this may allow simplified Chinese readers to interpolate and generalize their skills to traditional characters. Thus, transfer of perceptual expertise may be constrained by both the similarity in feature and the difference in exemplar variance between the categories.

The brain‐derived neurotrophic factor (BDNF)‐tyrosine kinase B (TrkB) (BDNF‐TrkB) signalling pathway plays a crucial role in regulating learning and memory. Synaptophysin provides the structural basis for synaptic plasticity and depends on BDNF processing and subsequent TrkB signalling. Our previous studies demonstrated that maternal exposure to propofol during late stages of pregnancy impaired learning and memory in rat offspring. The purpose of this study is to investigate whether the BDNF‐TrkB signalling pathway is involved in propofol‐induced learning and memory impairments. Propofol was intravenously infused into pregnant rats for 4 hrs on gestational day 18 (E18). Thirty days after birth, learning and memory of offspring was assessed by the Morris water maze (MWM) test. After the MWM test, BDNF and TrkB transcript and protein levels were measured in rat offspring hippocampus tissues using real‐time PCR (RT‐PCR) and immunohistochemistry (IHC), respectively. The levels of phosphorylated‐TrkB (phospho‐TrkB) and synaptophysin were measured by western blot. It was discovered that maternal exposure to propofol on day E18 impaired spatial learning and memory of rat offspring, decreased mRNA and protein levels of BDNF and TrkB, and decreased the levels of both phospho‐TrkB and synaptophysin in the hippocampus. Furthermore, the TrkB agonist 7,8‐dihydroxyflavone (7,8‐DHF) reversed all of the observed changes. Treatment with 7,8‐DHF had no significant effects on the offspring that were not exposed to propofol. The results herein indicate that maternal exposure to propofol during the late stages of pregnancy impairs spatial learning and memory of offspring by disturbing the BDNF‐TrkB signalling pathway. The TrkB agonist 7,8‐DHF might be a potential therapy for learning and memory impairments induced by maternal propofol exposure.