Older adults who laugh more often are less likely to develop depression, according to a large study conducted in Japan. These findings suggest that laughter in everyday life, not just structured therapy sessions, could play a role in maintaining mental health in later life. The study was published in the Journal of Affective Disorders.
Depression is common in later life, affecting an estimated 10 to 20 percent of older adults around the world. It can lead to a range of serious health problems, such as heart disease, dementia, and even early death. Despite its wide-ranging impact, depression often goes undetected or untreated in older adults, particularly those who live independently in the community.
Because of this, public health researchers are increasingly interested in prevention strategies that could reduce the risk of developing depression. One area that has received attention is social engagement. Studies have indicated that staying socially active and maintaining relationships may help protect against depression.
Laughter, which often occurs during social interactions, is known to provide physical and mental health benefits. It may reduce stress hormones, support immune function, and improve mood. While structured laughter therapy has shown positive effects in reducing depressive symptoms, there has been limited long-term research on whether spontaneous laughter in daily life can actually prevent depression from developing in the first place. The new study was designed to help answer that question.
“This study was motivated by a long-standing debate on a bidirectional relationship in which whether reduced laughter precedes depression or whether depressive symptoms suppresses laughter,” said study author Yudai Tamada, lecturer at the Tohoku University Graduate School of Dentistry. “In other words, there was a possibility that reduced laughter appears both as a risk factor for future depression and as a symptom once depression is present. Hence, we conducted this study to test the former hypothesis, reduced laughter is associated with a greater risk of subsequent depressive symptoms.”
The study used data from the Japan Gerontological Evaluation Study, which tracks the health and well-being of older adults across Japan. Researchers focused on three time points: 2016, 2019, and 2022. They analyzed information from 32,666 adults who completed surveys during all three of these years. All participants were at least 65 years old and were living independently at the start of the study.
The researchers asked participants in 2019 how often they laughed out loud. They could choose from four answers: almost every day, one to five days per week, one to three days per month, or never or almost never. The participants also completed a questionnaire measuring depressive symptoms in both 2016 and 2022. The researchers used this information to identify who had developed depression during the six-year period.
At the start of the study, just under half of participants said they laughed almost every day. Another 41 percent said they laughed between one and five days per week. Around 12 percent reported laughing only a few days per month, and about 3 percent said they almost never laughed.
By 2022, roughly 15 percent of participants had developed symptoms of depression. When the researchers analyzed the data, they found a strong association between how often someone laughed in 2019 and their likelihood of developing depression by 2022. Compared to those who laughed nearly every day, people who laughed one to five days per week were 25 percent more likely to become depressed. Those who laughed only one to three days per month had a 26 percent higher risk. And participants who rarely or never laughed had a nearly 50 percent higher risk of developing depression.
These associations held even after the researchers took into account a wide range of factors that could influence both mood and laughter. These included age, income, marital status, physical health conditions, cognitive function, and social participation. The findings also showed a dose-response trend. In other words, the less frequently someone laughed, the more likely they were to develop depression. This pattern provides additional support for a possible link between daily laughter and long-term mental health.
One possibility is that laughter reflects a person’s overall social connectedness. People are more likely to laugh when spending time with friends or engaging in enjoyable group activities. In that sense, laughter could be both a signal of social engagement and a mechanism that supports well-being. It may also trigger physical responses in the body that reduce stress or improve mood, contributing to resilience over time.
“We have previously reported that laughing with others is more beneficial for health than laughing alone,” Tamada told PsyPost. “Based on these findings, we hope people will become more socially active, for example by meeting friends more often, and will find more opportunities to laugh in their everyday lives to improve their mental and physical health.
The study provides evidence that frequent laughter may help prevent depression in older adults, but there are some limitations to consider. The measure of laughter was based on self-report, which may be influenced by how participants perceive themselves or how they want to be seen by others. People who were already feeling low or withdrawn might have underreported how often they laughed, even if their actual behavior had not changed much. The researchers attempted to minimize this issue by controlling for earlier levels of depressive symptoms.
Another limitation is that the study could not fully account for all possible influences on both laughter and depression. For example, sleep problems and anxiety were not measured, even though they are likely to be connected to both mood and emotional expression. Although the researchers conducted statistical tests to estimate how strong any missing factors would need to be to change the results, unmeasured influences cannot be ruled out completely.
There is also the question of whether the results can be generalized beyond the Japanese context. Cultural attitudes toward laughter and emotional expression can vary, and what is considered typical or appropriate in one country may not be the same in another. That said, the researchers point out that many of the biological effects of laughter, such as changes in stress hormones and immune response, are not specific to any one culture.
Future studies could explore whether programs designed to encourage more daily laughter, perhaps through social activities or community engagement, can reduce the risk of depression in older populations. It may also be useful to examine whether similar patterns hold in younger groups or in other cultural settings.
The study, “Frequency of laughter and depression onset among older adults: A 6-year longitudinal study from the Japan Gerontological Evaluation Study,” was authored by Yudai Tamada, Masashige Saito, Tetsuya Ohira, Kokoro Shirai, Chikae Yamaguchi, Kohei Hasebe, Katsunori Kondo, Ken Osaka, and Kenji Takeuchi.
