Mood Munchies: Chocolate and Depression

Abstract & Commentary

By Russell H. Greenfield, MD, Editor

Synopsis: Increased intake of chocolate was associated with higher rates of depression on a mood screening instrument in this cross-sectional study. Whether cause and effect or self-treatment, the generally accepted idea that chocolate is comfort food appears in doubt.

Source: Rose N, et al. Mood food: Chocolate and depressive symptoms in a cross-sectional analysis. Arch Intern Med 2010;170:699-703.

The authors of this cross-sectional study gleaned data from an independent investigation of the noncardiac effects of lowering cholesterol levels to explore the relationship between chocolate consumption and depressed mood in adults. Initially, 1,018 people in San Diego aged 20-85 years (694 men; mean age, 58 years; mean BMI, 27.8 kg/m2; > 50% college graduates) were screened for participation in the trial, of which 1,009 completed a study-specific "Statin Study Questionnaire" chocolate consumption (SSQ-C) question: "How many times a week do you consume chocolate?" A small number (n = 78; 35 men) were taking antidepressant medication and were subsequently removed from consideration, such that the primary analysis focused on data from 931 participants.

Subjects completed the Center for Epidemiological Studies-Depression Scale (CES-D), a validated screening instrument related to mood. A score ≥ 16 was considered positive and used as a cutoff; a second cutoff of 22 was used to signify the possible presence of major depression.

A Food Frequency Questionnaire specific to chocolate intake (FFQ-C) was used; a medium serving was considered 1 ounce (28 g) of chocolate candy. Proportionately, a small serving was deemed equal to one-half a medium serving, and a large serving equal to 1.5 medium servings. Responses were converted to per-month consumption to provide a unified metric. Frequency (times/month) and rate of chocolate consumption (servings/month) were captured using the FFQ-C, while frequency (times/week) was determined with the SSQ-C. A number of other foods and specific nutrients were analyzed to assess for specificity of findings associated with chocolate intake.

Participants' mean CES-D score was 7.7 (range, 0-45). Mean chocolate consumption values were 6.0 medium servings/month and 6.0 times/month per responses to the FFQ-C, and 2.0 servings/week according to SSQ-C results. Those subjects with a CES-D score ≥ 16 reported significantly higher chocolate intake than those with lower CES-D scores (findings significant for FFQ-C times/month, FFQ-C servings/month, and SSQ-C times/week). Significance of the findings was evident with a cutoff point of 16, as well as with a cutoff of 22, and the findings were independently significant for men and women. The findings were not influenced by differential intake of high-antioxidant or other types of foods or caffeine ingestion, and BMI did not vary by CES-D score. The authors concluded that people with higher depression rating scores consume greater amounts of chocolate.

Commentary

People commonly joke about turning to chocolate as "comfort food," a perspective that seems well-ingrained in society but one lacking significant supportive data.1 On the flip side, a few studies have found high rates of chocolate consumption to be associated with worsened mood, and one study looking at groups of people reported an increased suicide rate.

It's important to remember that the investigation was designed with a completely different purpose in mind, and that it is cross-sectional in nature, so causality cannot be assumed. The authors were forthright in pointing out these limitations, as well as the fact that a positive score on the CES-D is not strictly equivalent to a clinical diagnosis of depression, and that different chocolate products contain myriad constituents. Still, the strengths of the study findings are formidable, with consistent findings for both men and women, and analyses suggesting specificity of the chocolate-related results.

The authors posit that a depressed emotional state could trigger chocolate cravings as self-treatment; that, like alcohol, chocolate could offer initial benefits but long-term challenges to mood; and the possibility that specific physiologic changes could drive both chocolate cravings and depression. Regardless, it is intriguing (if not dispiriting...) to consider that frequent chocolate ingestion may not be a reasonable treatment for the blues, and might even contribute to them. Such sobering news needs to be appropriately confirmed, of course, but compels me to reach for a small piece of dark chocolate. Perhaps I should hold off, but I'm going to rationalize that it's good for my heart.

Reference

1. Parker G, et al. Mood state effects of chocolate. J Affect Disord 2006;92:149-159.