Caffeine Consumption, Psychological Distress, and Insomnia in a Cohort of Individuals with Depression

Abstract

INTRODUCTION: Caffeine is a widely consumed psychoactive compound that can cause anxiety and sleep difficulties, in part due to genetic variation. We investigated the association between caffeine consumption, psychological distress, and sleep difficulties in a genetically informative cohort of individuals with a history of depression. METHODS: Survey data and genetic information were sourced from the Australian Genetics of Depression Study (AGDS [n = 20,689, %(female) = 75%, mean age = 43 ± 15 years]). Associations between caffeine consumption and symptoms of distress and sleep disturbance, as well as 9 genetic variants associated with caffeine consumption behaviour, were assessed using linear regression. RESULTS: The highest consumers of caffeine reported higher psychological distress measured by the Kessler 10 scale (β = 1.21, SE = 0.25, p = 1.4 × 10(-6)) compared to the lowest consumers. Consumption was associated with 2 genetic variants with effect sizes ∼0.35 additional caffeinated drinks/day between opposite homozygotes (p < 0.005). A deletion near MMS22L/POU3F2 was associated with 10% increased odds of reporting caffeine susceptibility (OR = 1.1 per deletion [95% CI: 1.04-1.17], p = 0.002). CONCLUSIONS: Higher rates of caffeine consumption were associated with higher levels of psychological distress, but not insomnia, in individuals with a history of depression. While the direction of causality is unclear, caffeine consumption may be a modifiable factor to reduce distress in individuals susceptible to mental health problems. Some of the previous findings of common variant associations with caffeine consumption and susceptibility were replicated.

Caffeine is the world’s most popular and available mind-altering drug, commonly found in coffee. Typical caffeine use is generally safe, but caffeine can also cause anxiety and insomnia when consumed in large amounts, or by especially susceptible people. Several genetic variants have been found to change how people react to caffeine. Our study sought to investigate the nature of these relationships. We used data from the Australian Genetics of Depression Study (AGDS), where ∼12,000 people with a history of depression were surveyed about their mental health and behaviours like caffeine consumption. A total of ∼9,000 AGDS participants provided information on genetic variants of interest. We used linear modelling to see how caffeine consumption correlated with psychological distress, sleep quality, substance use, and genetic variants. People who drank high amounts of caffeine each day were more distressed but did not differ in their sleep. Those who said that caffeine interferes with their sleep drank less caffeine. Participants carrying particular genetic variants tended to have more caffeinated drinks each day, or be more susceptible to caffeine. Our survey data only contain one slice of time, so we cannot say whether caffeine causes distress or whether people use caffeine to alleviate symptoms caused by unrelated distress. Our data do not measure precise dosage, or account for tolerance built over time. These results indicate that changing one’s caffeine consumption could help reduce distress in people experiencing depression or similar illnesses.

eng