GUT FEELINGS: INVESTIGATING THE LINKS BETWEEN ACUTE GASTROINTESTINAL ILLNESS AND MENTAL HEALTH

Abstract

Background: Psychiatric patients have been well documented to have higher rates of physical illness compared to the general population. Treatments of chronic illnesses such as functional gastrointestinal disorders are beginning to incorporate integrated care models to simultaneously address psychiatric and physical symptoms. This is based on recent research emphasizing the importance of the gut-brain axis. However, the intricacies of connections between infectious diseases and mental illness remain unclear. Diarrheal disease and depression account for a disproportionate amount of the total global burden of disease, being the second and fourth greatest contributors respectively. This highlights the need to investigate the possible links between the two, and interactions along the gut-brain axis in general. Objectives: The objectives of this scoping review and thematic analysis was to explore what is known about infectious acute gastrointestinal illness and its relationship to depressive and anxiety symptoms. Ultimately, this review was intended to act as a case study of novel connections between infectious illnesses and mental illness. Methodology: Following Arksey & O’Malley’s framework, five databases (EMBASE, MedLine, PsychInfo, Global Health, HealthStar) were searched resulting in 1156 titles and abstracts. These were screened for inclusion and produced a total of 17 articles included for review and synthesis. Results: Three major themes were identified: 1) Connections between physical and mental status within this context can occur via i) the microbiome, ii) the immune system, iii) the nervous system, and iv) the endocrine system; 2) Bidirectionality of the gut-brain axis is key in understanding cross-talk between symptoms; 3) Integration of care options might result in improved health outcomes. Conclusion: These findings demonstrate that holistic and integrated interventions must be considered not only for chronic and mental illnesses, but also for infectious and mental illnesses, based on the connections between AGI and depressive and anxiety symptoms. More research is required, particularly with human subjects, in order to further understand the connections between the gut and brain. Incorporation of this knowledge into new treatment plans will allow clinicians to deliver more effective care to their patients who suffer from a dual burden of disease.