Abstract

Stress Throughout the Lifespan: Influence of Childhood Adversity on the Relationship Between Gut Microbiome, Diet Quality and Affective Symptoms in Adulthood

Adverse childhood experiences may predict the onset and severity of mental illnesses, including major depressive disorder (MDD) and generalized anxiety disorder (GAD). Appreciable evidence also indicates that a poor quality diet (high in processed foods and low in whole foods) is associated with depression and/or anxiety severity. It has been suggested that alterations in brain circuits involved in stress regulation as well as in stress-related disorders such as anxiety and depression promoted by childhood adversity could be associated with early changes in gut microbiota that persist into adulthood. The associations between gut microbial status, poor diet, and severity of anxiety and depressive symptoms are likely bidirectional, working in a forward-feeding cycle in which a pathology-promoting microbial signature or poor diet would increase symptom severity, and in which depressive and anxiety symptoms would influence microbiota status and dietary choices. In the current study, we examined if childhood adversity and diet quality influenced the relationships between gut microbiota and symptoms severity in the context of depression and anxiety. Individuals with a diagnosis of GAD and/or MDD as well as healthy controls with subclinical symptoms completed questionnaires assessing severity of depressive and anxiety symptoms, childhood adversity, and dietary patterns. Participants also provided a stool sample to determine gut microbiota composition. Our data show that a poor quality diet was related to more severe depressive symptoms only in individuals with moderate-to-severe childhood trauma, with high levels of sexual abuse, emotional neglect, and physical neglect were the trauma subtypes moderating the association between diet quality and depressive symptoms. Importantly, the reduced amounts of the anti-inflammatory commensal Faecalibacterium prausnitzii found in individuals with MDD were negatively correlated to symptom severity only in individuals with moderate-to-high scores of childhood adversity. These data suggest that experiencing trauma early in life might trigger developmental changes in the gut microbiota that may ultimately impact mood in adulthood, and that diet quality may potentially play a role in this regard.