Neuroinflammation and the possible etiology of various mental illnesses A brain running on inflammation seems to be "a brain on fire":. Some people describe their worst times in terms of an inferno. "It would be like my brain was on fire" "I would pass out from sheer exhaustion. I would be up at three, four in the morning, unable to sleep... but then my brain would be on the second my eyes would open." Mental illnesses and ASD seem to be strongly related to (neuro)inflammation, activation of inflammation in animal models leads to behavioural abnormalities. That said, it is suggested to be at best one cause of depression [1]. Schizophrenia and autism spectrum disorders share core symptoms and overlap in many ways pathologically, mainly by extensive microglial activation and similar behavioural attributes, this microglial activation also extends to brain injuries. Psychological stress activates inflammation and that this activation would be found to predict the later development of pathology. Social isolation/feeling lonely is associated with systemic inflammation. There is evidence that a range of psychosocial stressors lead to elevated microglial activity [2]. Neuroticism has also been associated with higher levels of inflammatory markers while conscientiousness has been associated with lower inflammatory markers [3]. Chronic neuroinflammation and the loss of neurotrophic factors promotes 'locked in' behavioural inflexibility and promotes the pathogenesis of disorders such as addictions and feeds antisocial personality traits [4]. A multitude of studies support the notion that inflammatory processes form an integral part of the mechanisms precipitating addictions [5]. It appears elevated neuroinflammation is important throughout the cortico-striato-thalamo- cortical circuit of obsessive compulsive disorder, too [6] "Inflammatory deregulation as an etiological factor appears to be a plausible hypothesis to explain why 30–50% of the depressive patients do not respond to conventional therapy. The presence of continuous stimuli that increase the levels of pro-inflammatory cytokines in the brain can cause neurotransmitter imbalance, neuroinflammation and neurodegeneration. Intervention in this process could be an 1 important aim to prevent further damage in the CNS" [7] Anti-inflammatory medications routinely used in medical practice, such as nonsteroidal anti-inflammatory drugs, omega-3 fatty acids, and statins, might alleviate psychiatric symptoms and reduce cardiac mortality in people with schizophrenia [8] [1] The inflammation connection https://www.psychiatrictimes.com/view/introduction- inflammation-connection [2] Stress and neuroinflammation: a systematic review of the effects of stress on microglia and the implications for mental illness https://www.ncbi.nlm.nih.gov/pubmed/26847047 [3] Stress and neuroinflammation: a systematic review of the effects of stress on microglia and the implications for mental illness https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4544833/ [4] More inflammation but less brain-derived neurotrophic factor in antisocial personality disorder https://www.ncbi.nlm.nih.gov/pubmed/28810156 [5] Addiction: A dysregulation of satiety and inflammatory processes https://www.ncbi.nlm.nih.gov/pubmed/29054292 [6] Inflammation in the Neurocircuitry of Obsessive-Compulsive Disorder https://www.ncbi.nlm.nih.gov/pubmed/28636705 [7] Anti-inflammatory treatment for major depressive disorder: implications for patients with an elevated immune profile and non-responders to standard antidepressant therapy https://doi.org/10.1177/0269881117711708 [8] https://www.mdedge.com/psychiatry/article/108302/schizophrenia-other-psychotic- disorders/can-anti-inflammatory-medications 2