Scientists find evidence that an “optimal sexual frequency” exists and mitigates depression

New research published in the Journal of Affective Disorders suggests that people who engage in sexual activity at least once a week are less likely to experience symptoms of depression. Drawing from a large, nationally representative sample of U.S. adults, the study found that sexual frequency was negatively associated with depression, even after accounting for factors like age, physical health, and socioeconomic status. The findings also suggest that having sex one to two times per week may offer the greatest psychological benefits.

The study was conducted by researchers from The First Affiliated Hospital of Shenzhen University and Shantou University Medical College. Their goal was to explore whether sexual activity—a commonly overlooked aspect of lifestyle—might serve as a behavioral indicator related to mental health. While sex is widely recognized for its physical health benefits, its role in emotional well-being is less often studied. Depression remains one of the leading contributors to disability and reduced quality of life, and identifying modifiable lifestyle factors that could reduce its burden is an important goal for public health researchers.

To investigate this question, the researchers analyzed data from the National Health and Nutrition Examination Survey (NHANES), a long-running project that collects health and behavior information from a representative sample of adults in the United States. They focused on data collected between 2005 and 2016, selecting participants aged 20 to 59 who reported both their sexual activity over the past year and completed a standard depression questionnaire known as the Patient Health Questionnaire-9 (PHQ-9).

After applying exclusion criteria, the final sample included 14,741 individuals. About 7.5% of these participants had PHQ-9 scores indicating moderate to severe depression. Sexual activity was categorized into three levels: less than once per month, more than once per month but less than once per week, and at least once per week. The researchers also collected information on a wide range of other variables, including age, gender, race, income, education, marital status, insurance coverage, and physical health as measured by the Charlson Comorbidity Index.

Using statistical models that adjusted for these potential confounders, the researchers found a clear association: people who reported having sex at least once per week had significantly lower odds of depression compared to those who had sex less than once per month. Specifically, weekly sexual activity was associated with a 24% reduction in the odds of depression. Those who reported sex more than once per month but less than weekly had about a 23% reduction in depression odds.

The researchers also used a flexible modeling technique called restricted cubic splines to examine whether the relationship between sexual frequency and depression was linear or nonlinear. The analysis revealed what they described as a “saturation effect”—the psychological benefits of sex appeared to peak at a frequency of 52 to 103 times per year, or about one to two times per week. Increasing sexual frequency beyond this range did not seem to offer additional protection against depression.

These findings remained robust across a variety of statistical checks. For example, when participants taking antidepressants were excluded from the sample, the association between sexual frequency and depression remained significant. The researchers also conducted sensitivity analyses using techniques like multiple imputation to handle missing data and inverse probability weighting to adjust for potential biases. Across these different approaches, the pattern held: more frequent sex was associated with lower odds of depression.

Interestingly, the protective association between sex and depression appeared to be stronger in certain groups. Younger adults (ages 20–39), Mexican American and non-Hispanic White participants, and those without health insurance all showed stronger associations. However, the researchers did not find significant differences by gender, income level, or education, and there were no statistically significant interaction effects between sexual frequency and these subgroup variables.

However, it is important to note that the study was cross-sectional, which means that all data were collected at a single point in time. As a result, the researchers could not determine whether reduced sexual frequency leads to depression, whether depression reduces sexual activity, or whether both are influenced by other shared factors. Self-reported sexual activity may also be subject to recall bias or social desirability effects. In addition, the study did not account for sexual orientation, relationship satisfaction, or other contextual factors that might influence both sexual activity and mental health.

Still, the authors argue that sexual frequency may serve as a useful behavioral marker in mental health screening and treatment. They note that sexual activity is a multidimensional experience that combines emotional, physical, and relational elements. Regular sexual activity can contribute to stress relief, intimacy, and emotional bonding—all of which may play a role in protecting mental health. On a physiological level, sexual activity is associated with the release of endorphins and other neurochemicals that are known to elevate mood. It may also function as a form of physical exercise, which itself has well-established benefits for psychological well-being.

The researchers caution against interpreting their findings as encouragement to increase sexual activity indiscriminately. Instead, they suggest that maintaining a moderate, consistent level of sexual activity—particularly within the context of a satisfying relationship—may support emotional health. They also emphasize the need for health professionals to include sexual well-being in their assessments of mental health, as sexual dysfunction or low sexual frequency can be both a symptom and a contributing factor in depression. For patients taking antidepressants, which often have sexual side effects, these considerations may be especially important.

The study, “Optimal sexual frequency may exist and help mitigate depression odds in young and middle-aged U.S. citizens: A cross-sectional study,” was authored by Mutong Chen, Ruibin Yi, and Zhongfu Zhang.