Do common antibiotic treatments influence emotional processing?

• Published in: Physiology & behavior Vol. 255; p. 113900
• Main Authors: Johnson, Katerina V.-A., Steenbergen, Laura
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.10.2022
• Subjects: adults; Antibiotics; anxiety; behavior; brain; cognition; digestive system; Emotional processing; Heart rate; humans; immune system; Immunoglobulin A; intestinal microorganisms; microbiome; Microbiome–gut–brain axis; psychophysiology; Heart rate; Emotional processing; Microbiome–gut–brain axis; Antibiotics; Immunoglobulin A
• ISSN: 0031-9384; 1873-507X; 1873-507X
• DOI: 10.1016/j.physbeh.2022.113900

•We investigate the association between antibiotic treatment and emotional processing.•Antibiotic group showed increased attention bias towards sad faces in dot-probe task.•There were no differences in questionnaire scores or emotional biases in memory.•Findings consistent with studies linking antibiotics to increased risk of depression.•Implications for considering recent antibiotic use as a possible exclusion criterion. Antibiotics are among the most commonly prescribed medications worldwide, yet research in recent years has revealed the detrimental effect they can have on the human microbiome, with implications for health. The community of microorganisms inhabiting the gut has been shown to regulate physiological and neural processes. Since studies in both humans and animal models have revealed that the gut microbiome can affect the brain, influencing emotion and cognition, here we investigate whether antibiotic treatment is associated with changes in emotional processing and mood with a between-subject design in 105 young healthy adult volunteers, using both psychological tests and questionnaires. As both the immune system and vagal signalling can mediate the microbiome–gut–brain axis, we also assess whether there is any evidence of such changes in participant physiology. We find that individuals who have taken antibiotics in the past three months show a stronger emotional bias towards sadness and at a physiological level they have a higher heart rate (though this does not mediate the relationship with negative bias). While we cannot rule out a possible role of prior infection, our findings are in any case highly relevant in light of research revealing that antibiotics are linked to increased susceptibility to depression and anxiety. Our results also have implications for listing antibiotic use as an exclusion criterion in studies on emotional processing and psychophysiology.