Inverse association between caffeine intake and depressive symptoms in US adults: data from National Health and Nutrition Examination Survey (NHANES) 2005-2006.

The objective of this study was to examine the association between caffeine consumption and depressive symptoms. We used data from the 2005-06 National Health and Nutritional Examination Surveys (NHANES). A total of 4737 individuals aged ≥ 18 years who answered the caffeine intake and PHQ-9 questionnaires were selected for this study. Depressive symptoms were assessed using the 9-item Patient Health Questionnaire (PHQ-9) with total scores between 0 and 27. Those with PHQ-9 total scores ≥ 10 were considered as having clinically relevant depression. To investigate the association of caffeine intake and PHQ-9 scores, a multiple logistic regression was used in different models. The overall weighted prevalence of depression was 5.5% (4.3% in men and 6.6% in women). After controlling for potential confounders (age, sex, family PIR, education, marital status, disease history, sleep disorders, thyroid problems, physical activity, social support, smoking, total energy, and cholesterol, retinol, vitamin A, beta-carotene, beta-criptoxanthin, vitamin B1, iron, and phosphorus levels), a significant nonlinear inverse association between caffeine consumption and PHQ-9 scores was observed. In conclusion, caffeine's psychostimulant properties appear to protect against depressive symptoms; however, additional prospective studies are required to ascertain whether or not caffeine consumption can lead to a decrease in depressive symptoms.