The Microbiome and Mental Health: Looking Back, Moving Forward with Lessons from Allergic Diseases

Abstract

Relationships between gastrointestinal viscera and human emotions have been documented by virtually all medical traditions known to date. The focus on this relationship has waxed and waned through the centuries, with noted surges in interest driven by cultural forces. Here we explore some of this history and the emerging trends in experimental and clinical research. In particular, we pay specific attention to how the hygiene hypothesis and emerging research on traditional dietary patterns has helped re-ignite interest in the use of microbes to support mental health. At present, the application of microbes and their structural parts as a means to positively influence mental health is an area filled with promise. However, there are many limitations within this new paradigm shift in neuropsychiatry. Impediments that could block translation of encouraging experimental studies include environmental forces that work toward dysbiosis, perhaps none more important than westernized dietary patterns. On the other hand, it is likely that specific dietary choices may amplify the value of future microbial-based therapeutics. Pre-clinical and clinical research involving microbiota and allergic disorders has predated recent work in psychiatry, an early start that provides valuable lessons. The microbiome is intimately connected to diet, nutrition, and other lifestyle variables; microbial-based psychopharmacology will need to consider this contextual application, otherwise the ceiling of clinical expectations will likely need to be lowered.

An exposome perspective: Early-life events and immune development in a changing world

“…14 In part, this might explain the high levels of overlap between NCDs, such as allergic diseases and mental disorders. 14,15 The emerging science of the microbiome and its influence on early-life immune priming to be discussed below has forced a total environment perspective.…”

Microglia and Autism Spectrum Disorder: Overview of Current Evidence and Novel Immunomodulatory Treatment Options

“…Studies also have suggested relationship with symptom severity in ASD patients and gastrointestinal disturbances 57). Gut bacteria have been frequently implicated in ASD,58) and animal and human studies have demonstrated its correlation with behavioral disturbances 59–61). Interestingly, modeling MIA-induced ASD offspring in mice resulted not only in behavioral disturbance but also alterations in gut microbiota, which were however reversed by treatment with Bacteroides fragilis ( B. fragilis ) 62).…”

Features of Cutaneous Microbiome in Children With Atopic Dermatitis and New Pathogenetic Therapy Options

“…Нарушение регуляции указанных выше факторов может нарушить структуру микробного сообщества, привести к развитию состояния, известного как «дисбиоз», характеризуемого доминированием одного представителя из всего разнообразия микроорганизмов [9]. Потеря функциональности или даже исчезновение древних видов бактерий микробиома человека с постоянным изменением образа жизни поднимает важные вопросы о взаимосвязи между состоянием окружающей среды и воспалительными заболеваниями [9], которые включают в себя не только аллергию и иммунные болезни, но и многие другие состояния, включая психическое здоровье, на которые влияют как иммунная система, так и микробиом [10]. Оригинальные постулаты «гигиенической гипотезы» получили развитие в теории биоразнообразия, согласно которой среда, богатая различной макро-и микробиотой, оказывает значимое влияние на микробную экосистему человека.…”