Neuroinflammation and Suicide: Are the Gut-Brain Axis and Unhealthy Lifestyle the Key?

Increased brain microglia activation and density have been documented in different severe mental disorders by both postmortem and neuroimaging studies. These brain changes seem to be linked to suicidal behavior in a transdiagnostic way. The gut microbiome has a central role in modulating the immune system and abnormalities in gut-brain interactions have been associated with chronic systemic inflammation and neuroinflammation. Neuroinflammation is known to impact neurotransmission and neuroplasticity, potentially leading to mood abnormalities, cognitive difficulties and suicidality. The gut microbiome is heavily influenced by lifestyle factors such as diet, physical activity, substance use, stress management, and sleep. Unhealthy lifestyle habits have been associated with increased suicidality and can disrupt the gut microbiome, contributing to neuroinflammation through an imbalance in microbial signaling molecules. Brain-gut-microbiome interactions play an important role in moderating the impact of lifestyle habits on brain and behavior, constituting an important neurobiological factor associated with suicidality.