Now, preliminary findings of research presented at the 2016 Annual Meeting of the American Psychiatric Association (APA) in Atlanta, Georgia, indicate a likely connection between obsessive-compulsive disorder (OCD) and a disrupted gut microbial milieu.5....It is worth noting that in this sample, comorbid generalized anxiety disorder (GAD), major depressive disorder (MDD), social anxiety disorder (SAD), attention-deficit/hyperactivity disorder (ADHD), or tic disorder was established in 40% to 60% of patients diagnosed with OCD.

Temporal Association of Certain Neuropsychiatric Disorders Following Vaccination of Children and Adolescents: A Pilot Case–Control Study - There is a considerable body of scientific evidence indicating that the immune system plays a key role in normal brain development and in the pathobiology of several neuropsychiatric disorders (1). These include obsessive–compulsive disorder (OCD) (2,3), anorexia nervosa (AN) (4), tic disorders (5), attention deficit hyperactivity disorder (ADHD) (6), major depressive disorder (7), and bipolar disorder (8)....Receipt of any vaccine in the previous 6 months was highest for children with AN (21.4%), followed by OCD (15.9%) and tic disorder (15.8%) ... In general, vaccination rates were highest among children in the AN, OCD, and tic disorder groups....Children with tic disorder were more likely to have received an influenza or a meningococcal vaccine in the previous 6 or 12 months.  

It should be noted that both of those vaccines, influenza and meningococcal, can contain approximately 25 mcg. of Thimerosal .

Another aspect of this in both autism and neuropsychiatric disorders like PANDAS and PANS, is that mercury can affect the MICROBIOME, the bacteria that play a huge part in our body's physical and mental health.  

A Study in Balance: How Microbiomes Are Changing the Shape of Environmental Health   

......prevalent and well-defined external human health hazards—suggest the role of commensal bacteria may equal or exceed that of genetic polymorphisms that regulate metal transformations within the body....Thousands of studies have shown that mercury affects many metabolic processes and organ systems in humans and experimental animals. Silbergeld says research by her laboratory and others indicates inorganic mercury can also impact the mucosal immune system, for instance by increasing the production of proinflammatory cytokines and serum levels of biomarkers of immune alteration related to autoimmunity. ...humans have generated unprecedented environments with high concentrations of antibiotics and metals, especially mercury, inside our bodies.

Summers says bacterial exposure to metals such as mercury can contribute to antimicrobial resistance because many transferrable plasmids carry genes for multiple types resistance. In other words, in the process of developing metal resistance, a bacterium may also become resistant to an antibiotic it hasn’t even encountered. 

Xenobiotics: Interaction with the Intestinal Microflora 

....mercury exposure increased the abundance of mercury-resistant bacteria, but also found that mercury exposure completely eliminated Bacteroidetes and elevated levels of Actinobacteria, Betaproteobacteria, and Alphaproteobacteria.....a recent epidemiological study found that probiotics have a protective effect against increases to blood levels of mercury in pregnant women (Bisanz et al. 2014), suggesting that modulation of a mercury-exposed gut microbiome could possibly counter the effects of mercury-exposure-related disease. However, there remains a need for more experimental studies that use animal models greater of similarity to humans as well as cutting-edge microbiome profiling techniques in order to better establish the relationship between mercury exposure and the gut microbiome.

Chemical transformation of xenobiotics by the human gut microbiota  

In addition to organic pollutants, human gut microbes modify the structures and alter the toxicities of various heavy metals, including bismuth, arsenic, and mercury. Mercury bioaccumulates in living organisms, posing a threat to human health, and gut microbial metabolism may affect mercury toxicity and lifetime in the body. Rat fecal samples reduce methylmercury (CH3Hg+) to the less toxic inorganic mercury, thereby facilitating mercury excretion from the host (84). Depletion of the gut flora in rats and mice can result in the accumulation of methylmercury, thereby causing neurological symptoms (85). The enzymes responsible for this protective activity could include homologs of the demethylating, organomercuric lyase (MerB) and mercuric reductase (MerA), which have been identified in human isolates (86). However, the abundance of mer genes did not correlate with fecal methylmercury levels in a recent clinical study, raising the possibility of additional enzymes or indirect effects (87). Notably, incubation of a mixture of 16 metal(oid)s with suspensions from an in vitro simulator of the GI tract resulted in volatilization of many metal species and the production of As/S compounds not previously observed in biological systems (88). These studies indicate that there are major gaps in our knowledge of the gut microbiota’s interactions with heavy metals and the resulting toxicological implications.

Lisa Helbling Chadwick, the NIEHS liaison for the Human Microbiome Project, says the institute is increasing its focus on the impact of microbiomes on toxicology. “One thing we are really interested in at NIEHS is understanding how individuals respond differently to exposures, what makes one person more susceptible to adverse health outcomes from an exposure than another,” she says. “Genetics only partially explains this.”

Thoughts?  Feelings?  Solutions?  More research?

Teresa Conrick is Science Editor for Age of Autism.