Table 2.

Observational studies included in review (n = 11).

Author (s) and date	Study details and data collection	Focus/population	Measurement tools	Outcomes
Starkey et al. (2019) United States of America	Descriptive cross-sectional study. Participants recruited through nursing professional organisation. 12 weeks of weekly surveys. Sample: 146 nurses, 91.1 % female, M age 44 years, 63 % worked full time.	Focus: How receiving expressions of gratitude predicts physical health outcomes in acute care nurses Population: Nurses	· Self-developed ‘Gratitude expression and reception’ scale · Life Orientation Test · Quality Care Scale · Pittsburgh Sleep Quality Index · Health Event Checklist	Gratitude predicted sleep quality, sleep adequacy, headaches, and attempts to eat healthily.
Kim et al. (2019) South Korea	Descriptive cross-sectional study. Data collection – survey, single time point Sample: 360 nurses. Participants recruited from a single tertiary hospital. M age 34.1 years old, 99 % female.	Focus: To estimate the influence of resilience and gratitude disposition on psychological well‐being in Korean clinical nurses in variety of surgical, medical, and mixed wards Population: Nurses	· Gratitude Resentment and Appreciation Test · Dispositional Resilience Scale – 15 · Job Satisfaction Scale · Psychological Wellbeing Scale	Gratitude disposition had significant direct effect on psychological well‐being. Gratitude disposition had significant indirect effects through the effect on burnout, compassion satisfaction and job satisfaction.
Lau (2017) Hong Kong	Cross-sectional study. Participants recruited from 9 local non-government organisations who support providers of dementia-related care. Sample: 101 participants completed a face-to-face verbal questionnaire. Data collection on a single time point. M age 57.6 years, 82 % female. Participants were excluded if undergoing cancer treatment or structured counselling programs.	Focus: Investigate the role of gratitude in the coping process among familial caregivers of People With Dementia. Population: Caregivers	· Gratitude Adjective scale · Gratitude Questionnaire · Caregiver competence · Social support measures · Brief Coping Orientation to Problems Experienced scale · Caregiver burden- Zarit Burden Interview · Center for Epidemiological Studies – Depression Scale	Gratitude adjective positively related to social support and emotion-focused coping. Gratitude was associated with problem-focused coping as well as emotion-focused coping and associated with greater use of planning.
Lee et al. (2019) United States of America	Study 1: Experience sampling methodology. Sample: 51 employees, also enrolled as a part time Master of Business Administration student in a large United States of America university over 10 consecutive days. Demographic data collected 1 week before the daily surveys. 49 % were female, 80.4 were Caucasian, and worked an average of 50.6 h per week. Study 2: Critical Incident Technique, single time-point survey to capture two samples both a helper's perspective (sample 1) and receiver (sample 2) of help's perspective. Sample 1: 400 full time employees, 44.9 % female, 85 % Caucasian, 72.1 % aged between 20 and 39 years old Sample 2: 250 full-time employees, 41.3 female, 79.4 % Caucasian, 76.7 % aged between 20 and 39 years.	Focus: Association of receiving gratitude with prosocial impact and work engagement. Population: Employees in North America	· Likert scale.	Receipt of gratitude is associated with increases in perceived prosocial impact and work engagement the following day.

Author (s) and date	Study details and data collection	Focus/population	Measurement tools	Results
Petrocchi and Couyoumdjian (2016) Italy	Descriptive Cross-sectional study. Data collection – survey, single time point, Sample: 410 participants. Participants recruited from mailing lists of a university and professional organisations and web advertising. M age 33.35 years old, 61.46 % female.	Focus: To evaluate possible mediation models for the relationship between gratitude and symptoms of depression and anxiety Population: Students, employed, unemployed adults.	· Gratitude Questionnaire · Forms of Self-Criticizing /attacking and Self-Reassuring Scale · Center for Epidemiological Studies – Depression Scale · Spielberger State-Trait Anxiety Inventory – Trait Form	Gratitude negatively correlated with self-criticising and self-attacking scales, and positively with the self-reassuring scale. Direct effect of gratitude on anxiety but partially mediated by self-criticising and self-reassuring pathway.
Lin (2015) Taiwan	Descriptive Cross-sectional study. Data collection – survey, single time point. Sample: 375 participants. Participants recruited from undergraduates studying at 9 universities in Taiwan. M age 20.3 years old, 65 % female.	Focus: To examine simultaneously the effect of gratitude on social, cognitive, physical, and psychological resources. Population: Undergraduate students	· Gratitude Questionnaire-6 (Chinese version) · Inventory of coping style · Inventory of social support · Inventory of negative emotions · Inventory of positive emotions · Satisfaction with Life Scale	Gratitude: · Was significantly associated with social support, emotional-companion support, and informational-tangible support. · Had significant effect on coping style, on problem-focused active coping, on problem-focused passive coping, on emotion-focused passive coping. · In high levels with problem focused active coping and emotion-focused active coping strategies · had a significant positive effect on negative emotions, specifically shame, anger, and on life satisfaction. · In low levels was associated with negative emotions of shame and anger Positive emotion partially mediates the association between gratitude and life satisfaction.

Author (s) and date	Study details and data collection	Focus/population	Measurement tools	Results
Sirois and Wood (2017) United Kingdom	Longitudinal associations study. Data collection – paired survey, two time points, 6 months apart. Arthritis sample: Timepoint 1 423 participants, M age 44.5 years, 88.1 % female, Timepoint 2. 163 participants, M age 46.9, 91.6 % female. Inflammatory Bowel Disease sample: Timepoint 1: 427 participants, M age 35.6 years, 76.8 % female, Timepoint 2: 144 participants, M age 38.3 years, 77.8 % female. Participants from North America, United Kingdom, and other countries via support groups for arthritis and Inflammatory Bowel Disease, web advertisements, classified advertisements, and support foundation resource pages.	Focus: To evaluate associations between gratitude and depressive symptoms in chronic illness. Population: Adults with arthritis or Inflammatory Bowel Disease	· Gratitude questionnaire -6 · Center for Epidemiological Studies – Depression Scale · Medical Outcomes Survey 36 item short form · Arthritis Impact Measurement Scales · Inflammatory Bowel Disease Questionnaire · Perceived Stress Scale · Duke-University of North Carolina Functional Social Support · Illness Cognition Questionnaire · Psychological thriving scale (based on Carver's 1998 model of psychological thriving)	Gratitude was associated with lower depressive symptoms
Leppma et al. (2018) United States of America	Descriptive Cross-sectional study. Data collection – survey, single time point, 7 years after traumatic event. Sample: 113 participants. Participants recruited from one police department in New Orleans. M age 43.2 years old, 23.89 % female.	Focus: Role of gratitude in Post-traumatic Growth (post-Hurricane Katrina). Population: Police Officers	· Gratitude Questionnaire-6 · Satisfaction With Life · Recent Stressful Life Changes Questionnaire · Post-Traumatic Growth Inventory · Interpersonal Support Evaluation List	Gratitude was positively correlated with Post-Traumatic Growth (r = 0.20, p < .05), Satisfaction with life (r = 0.64, p < .001) and Social support (r = 0.69, p < .001)

Author (s) and date	Study details and data collection	Focus/population	· Measurement tools	Results
Vieselmeyer et al. (2017) United States of America	Descriptive Cross-sectional study. Data collection – survey, single time point, 4 months after a traumatic event. Sample: 359 participants, recruited from staff and students at a university where an on-campus shooting occurred. M age 27.26 years old, 75 % female, 66 % were undergraduate, 5 % postgraduate, 11 % faculty and 17 % staff members.	Focus: To investigate relationship between trauma and mental health outcomes following university campus shooting. Population: University students and staff	· Gratitude Questionnaire-6 · The Brief Trauma Questionnaire · Trauma exposure measures · Posttraumatic Stress Disorder Checklist – Civilian · Posttraumatic Growth Inventory · Connor-Davidson Resilience Scale- 25	Gratitude moderated effect of post-traumatic stress on post-trauma growth. High gratitude associated with high levels of post-trauma growth
McCanlies et al. (2014) United States of America	Descriptive Cross-sectional study. Data collection – survey, single time point, 7 years after traumatic event. Sample: 114 participants. Participants recruited from one police department in New Orleans. M age 43.0 years old, 26.3 % female.	Focus: To evaluate if higher levels of resilience, gratitude, life satisfaction, and posttraumatic growth were associated with lower Post-Traumatic Stress Disorder symptoms among law enforcement officers Population: Police Officers	· Gratitude Questionnaire · Post-Traumatic Growth Inventory · Post-Traumatic Stress Disorder Checklist – Civilian version · Connor-Davidson resilience scale · Satisfaction With Life Scale	Gratitude may be protective or mitigate symptoms of Post-Traumatic Stress Disorder. Expressing gratitude or having a grateful disposition is positively associated with increased life satisfaction, hope, and happiness

Author (s) and date	Study details and data collection	Focus/population	Measurement tools	Results
Jans-Beken et al. (2018) Netherlands	Four-wave prospective survey design. Data collection – survey, four time points, at Time 0, 6, 18, and 30 weeks from Time 0. Sample: 706 participants commenced, 280 completed. Adult participants recruited from the public in multiple advertisements. From completions, M age 48 years old, 71 % female.	Focus: To evaluate if a grateful trait influences psychopathology and subjective wellbeing. Population: Adults (general population)	· Dutch Short Gratitude, Resentment, and Appreciation Test · Dutch version of Symptom Check List -90 · Satisfaction With Life Scale · Positive and Negative Affect Scale	The grateful trait did not predict symptoms of psychopathology. Gratitude predicted subjective wellbeing.

Note: n = number, M= Mean, SD = Standard Deviation, p = Probability Value, r = correlation coefficient.