The Role of Gut Microbiota in Suicidality: Mechanisms, Evidence, and Future Directions

Suicidality, encompassing suicidal ideation, attempts, and completed suicide, continues to be a significant public health concern globally. Traditional research has emphasized genetic, neurobiological, and psychosocial factors; however, recent findings suggest that gut microbiota may play a crucial role in influencing suicidal behavior. The gut microbiota impacts neuroinflammation, neurotransmitter metabolism, and the hypothalamic–pituitary–adrenal (HPA) axis, all of which are associated with psychiatric disorders linked to suicidality. This review gathers current evidence on the gut–brain axis, investigating the role of microbiota in suicidality through mechanisms such as immune system modulation, serotonin regulation, and the stress response. We also consider the potential of microbiota-targeted interventions, such as probiotics and dietary changes, as innovative therapeutic strategies. Despite the accumulating evidence, research in this field remains limited, emphasizing the urgent need for further investigation to clarify the causal relationship between gut microbiota and suicidality.