*2.2. Materials*

All information provided was self-reported and completed online through the use of *Qualtrics* (SPA, London, England). Demographic information regarding gender, age, marital status, household and family composition, and years of education were collected. The following scales were used: the Depression, Anxiety, and Stress Scale (DASS-21) [28], the Warwick–Edinburgh Mental Well-Being Scale (WEMWBS) [29], the Brief Illness Perception Questionnaire (BIPQ) [30], and the ECQ (Berry and Carr 2020).

The DASS-21, which yields scores for depression, anxiety, and stress, was the primary measure for this study. Each scale contains 7 items. The Depression scale assesses dysphoria, hopelessness, devaluation of life, self-deprecation, lack of interest/involvement, anhedonia, and inertia. The Anxiety scale assesses autonomic arousal, skeletal muscle effects, situational anxiety, and subjective experience of anxious affect. The stress scale is sensitive to levels of chronic non-specific arousal. It assesses difficulty relaxing, nervous arousal, and being easily upset/agitated, irritable/over-reactive, and impatient. Scores for depression, anxiety and stress are calculated by summing the scores for the relevant items per scale; then, the DASS-21 subscale total is multiplied by 2 to give the final score for categorization into Normal, Mild, Moderate, Severe, or Extremely Severe. The reliability of the DASS-21 was considered acceptable [31] and has "good" Cronbach's alpha values of 0.81 and 0.89 for the depression and anxiety subscales, respectively. The alpha value for the stress subscale was observed at 0.78, which is considered "fair" [31].

The WEMWBS is a 14-item measure that focuses on the positive aspects of mental health and well-being including optimism, autonomy, agency, curiosity, clarity of thought, positive relationships, positive affect confidence, and having energy to spare [29]. High scores indicate greater well-being. The reliability of the WEMWBS is noted to be "good" within a student sample, with an observed Cronbach's alpha of 0.89 [31].

The BIPQ assesses the cognitive and emotional representations of illness. For this survey, we included the "Cognitive Perceptions" subscale adapted for COVID-19, which asks about the effect of COVID-19 on life (item 1); perceived duration of COVID-19 (item 2); control over COVID-19 (item 3); beliefs about the effectiveness of treatment for COVID-19 (item 4); and experience of COVID-19 symptoms (item 5). We further employed a single item to capture understanding of COVID-19 (item

7); items 1–5 are summed to give a total score for the "Cognitive Perceptions" scale. High BIPQ scores reflect negative perceptions of COVID-19. The reliability of the BIPQ has been shown to have a "good" Cronbach's alpha value of 0.85 [31].

The ECQ is a bespoke 34-item tool that measures perceptions of COVID-related stresses as well as gratitude arising from the COVID-19 crisis, as developed by the second and senior author following a review of the literature and discussions as part of a doctoral thesis (Supplementary Table S1). Items 1–25 are about COVID-19-related stresses. Items 26–34 are about things participants felt grateful for arising from the COVID-19 crisis. For COVID-19-related stresses, participants were asked, "In the past month, how much stress have you experienced as a result of the following things?" For COVID-19-related gratitude, participants were asked, "In the past month, how much has your experience of the COVID-19 crisis led you to feel grateful for the following things?" For all items, there are 5 response options: none, a little, some, quite a lot, and a great deal. The ECQ contains four a priori scales: Personal Stress (items 1–13), Parenting Stress (items 14–21), Older Aging Parent Stress (items 22–25) and Gratitude (items 26–34). Items in the Personal Stress scale cover financial hardship, difficulty getting supplies, loss of social contact, loss of routine, family conflict, conflicting media information about COVID-19, witnessing or worrying about COVID-19-related illness, hospitalization, death, and long-term effects for oneself and one's family. Items in the Parenting Stress scale (which are only relevant to respondents with children) cover school closure, preventing children having social contact with extended family and friends, helping children observe social distancing, handwashing, cough etiquette, and worrying about their health due to the presence an underlying condition that makes them vulnerable to COVID-19-related adverse outcomes. Items in the Older Aging Parent Stress scale (which are only relevant to respondents with aging parents) cover worrying about the impact of COVID-19 on older aging parents, especially loneliness, difficulty getting supplies, risk of illness, and risk of not receiving adequate medical care. Items in the Gratitude scale cover things that the COVID-19 crisis has made one feel grateful for including personal and family health, relationships, employment, social, sports and cultural events, community, schools, children's friendships, children's involvement in activities, and aging parents' health and safety. The ECQ is included in the supplemental materials.
