Recent studies have concluded that the expression of gratitude can have profound and positive effects on our health and moods. As Drs. Blaire and Rita Justice reported for the University of Texas Health Science Center, "a growing body of research shows that gratitude is truly amazing in its physical and psychosocial benefits."
In one study on gratitude, conducted by Robert A. Emmons, Ph.D., at the University of California at Davis and his colleague Mike McCullough at the University of Miami, randomly assigned participants were given one of three tasks. Each week, participants kept a short journal. One group briefly described five things they were grateful for that had occurred in the past week, another five recorded daily hassles from the previous week that displeased them, and the neutral group was asked to list five events or circumstances that affected them, but they were not told whether to focus on the positive or on the negative. Ten weeks later, participants in the gratitude group felt better about their lives as a whole and were a full 25 percent happier than the hassled group. They reported fewer health complaints and exercised an average of 1.5 hours more.
In a later study by Dr. Emmons, people were asked to write every day about things for which they were grateful. This daily practice led to greater increases in gratitude than did the weekly journaling in the first study. The results also showed another benefit, where the participants in the gratitude group reported offering others more emotional support or help with a personal problem, indicating that the gratitude exercise increased their goodwill towards others, or more technically, their "pro-social" motivation.
Several studies have shown depression to be inversely correlated to gratitude. It seems that the more grateful a person is, the less depressed they are. Philip Watkins, a clinical psychologist at Eastern Washington University, found that clinically depressed individuals showed significantly lower gratitude (nearly 50 percent less) than non-depressed controls.
Another study on gratitude was conducted with adults having congenital and adult-onset neuromuscular disorders (NMDs), with the majority having post-polio syndrome (PPS). Compared to those who were not jotting down their gratitude nightly, participants in the gratitude group reported more hours of sleep each night and feeling more refreshed upon awakening. The gratitude group also reported more satisfaction with their lives as a whole, felt more optimism about the upcoming week, and felt considerably more connected with others than did participants in the control group.
The positive changes were markedly noticeable to others; according to the researchers, "Spouses of the participants in the gratitude (group) reported that the participants appeared to have higher subjective well-being than did the spouses of the participants in the control (group)." Dr. John Gottman at the University of Washington has been researching marriages for two decades, and states that the conclusion of the research is that unless a couple is able to maintain a high ratio of positive to negative encounters (5:1 or greater), it is likely the marriage will end. With 90 percent accuracy, Gottman says he can predict, often after only three minutes of observation, which marriages are likely to flourish, and which are likely to end, based on a formula that for every negative expression (a complaint, frown, put-down, expression of anger) there needs to be about five positive ones (smiles, compliments, laughter, expressions of appreciation and gratitude).