How gratitude changes the brain

Many studies over the past ten years point to the benefits of gratitude: when people consciously remember good things, they become happier. But we could not rely on the results of the experiments – most of them were carried out on well-off people. We decided to find out if gratitude helps people with psychological problems.

Our study involved 300 people, most of them were students who faced psychological problems and signed up for psychotherapy sessions. The experiment started before the start of their therapy sessions: many participants suffered from a depressive or anxiety disorder and, on average, showed poor psychological health scores.

We randomly divided people into three groups, the participants of each of them went to sessions with a psychotherapist. The difference was in the extra task. Participants in the first group wrote a letter of thanks to someone once a week. Participants of the second described their thoughts and feelings caused by unpleasant situations in their lives. Members of the third group did not write anything. The experiment lasted three weeks.

A few weeks after the end of the experiment, we assessed the psychological health of the participants. In the first group, it improved significantly, in the other two there were no changes. This means that gratitude also helps those who struggle with psychological problems. We carefully analyzed the research data to understand how gratitude affects the brain and body.

Gratitude saves from destructive emotions

We compared the shares of words with positive and negative emotional evaluation, which were used in the texts by the participants of the two writing groups. Those who wrote thank you letters used more positive words and fewer negative emotional words compared to the second group.

However, positive words do not guarantee mental well-being. Only the participants who used fewer negative words subsequently improved their condition. The absence of negative statements led to a difference in state of mind between the two groups.

A thank you letter shifts attention away from emotions like resentment and envy. When you write about how grateful you are for others and how much good people have brought into your life, it’s hard to get stuck thinking about the bad.

Gratitude helps, even if it is kept secret.

We explained to the participants that thank you letters do not have to be sent to the recipients. And although only 23% of the participants decided to send what they had written, all the other members of the group also improved their condition, although the letters remained with them. So the actual transmission of gratitude does not play a key role.

Let’s say you want to write a thank you letter to someone but don’t dare. Write it anyway. Then decide whether to send or not. The act of writing the letter itself will help shift the focus away from negative thoughts and experiences.

The positive effects of thank you letters don’t happen overnight. In our study, it accumulated over time. A week after the end of the writing practices, we did not notice a difference in the state of mind between the participants in the three groups.

However, four weeks later, the first group to write thank you letters showed an improvement over the other two groups. 12 weeks after the end of the experiment, the difference became even more noticeable.

In other similar studies, the positive effect decreased over time. In our case, the opposite happened. Perhaps the participants discussed their letters, which increased the psychological impact of letter writing.

If you are writing a thank you letter, don’t expect immediate improvement. Be patient. Gratitude takes time to work.

Practicing gratitude improves health

Three months after the beginning of the psychotherapy session, we compared the state of several people who wrote letters of gratitude with those who did not write anything. I wanted to know if their brains began to process information differently.

To do this, we asked the participants to complete the “pay it to another” exercise, and in the process used a CT scanner to assess their brain activity. During the exercise, the “benefactor” gives everyone a small amount of money and asks them to pass it on to another person if they feel grateful. Participants then decide whether to donate the money to a good cause and determine the amount.

We wanted to separate donations motivated by gratitude from donations based on other feelings, such as debt or guilt. To do this, participants were asked to indicate how grateful they are to the “benefactor”, how much they want to participate in charity, and how guilty they feel if they do not. Participants also completed questionnaires that measured how grateful they are overall in life.

People who were generally more grateful gave more money to a good cause and showed higher neural sensitivity in the medial prefrontal cortex, an area responsible for learning and decision making. It can be assumed that more grateful people care more about exactly how to express their gratitude.

We also compared the brain activity of participants who wrote thank you letters with those of those who did not, and noticed a difference. The former showed more marked activity in the medial prefrontal cortex.

We found this effect three months after the start of the experiment. This means that the expression of gratitude has a long-term effect: constant practice trains the brain, and it becomes more sensitive to the experience of gratitude in the future. In the long run, this improves mental health.

Whether you’re going through a hard time right now, try writing a thank you letter. We spend most of our time and energy chasing what we don’t have. Gratitude draws our attention to the people who are already with us, as well as to the things that we already have.

About the Authors: Joshua Brown is a psychologist at Indiana University; Joel Wong is a psychologist at Indiana University.