Gratitude letters and well-being

Introduction: Positive psychologists study what helps people flourish. In this study, researchers tested whether regularly writing letters of gratitude increases well-being, and how long any effect lasts.

Participants: Two hundred forty adults aged 18 to 70 (mean age = 38) living in the United States signed up through a university research website advertised on social media. There were 151 women and 89 men. Participants reported their race/ethnicity as 70% White, 12% Black, 9% Hispanic or Latino, 6% Asian and 3% multiracial. Adults who were currently receiving treatment for depression were not eligible. Participants were not paid.

Method: A university institutional review board approved the study. Participants gave informed consent online, and their responses were stored under ID numbers. Participants were randomly assigned to one of two conditions (120 people each). Once a week for 4 weeks, they logged in and wrote for 15 minutes.

Gratitude condition: Participants wrote a letter to a specific person they had never properly thanked, describing what the person did and how it affected them. They did not have to send the letters.

Control condition: Participants described what they had done that day, without including feelings or opinions.

Before the study began (baseline), at the end of week 4 and at week 12, participants completed a 10-item well-being questionnaire (for example, 'I am satisfied with my life'), rating each item from 1 (strongly disagree) to 7 (strongly agree). Each person's well-being score was the average of the 10 ratings, from 1 to 7. At the end of the study, all participants were told the study's purpose, control participants were offered the gratitude-letter instructions, and everyone received a list of free, confidential support services.

Results and Discussion: The table shows the results. At week 4, the difference between the two conditions was statistically significant (p < .01), with an effect size of 0.40. At week 12, the difference was not statistically significant (p = .25). Eighty-five percent of participants completed all three questionnaires.