Medical literature documents a wide variety of adverse reactions to gluten, a component of wheat, barley and rye, among people with untreated celiac disease. Whether -- and how --an autoimmune condition that originates in the digestive tract can cause psychiatric and neurological disorders is a controversial issue among experts. However, scientific studies reporting that conditions such as clinical depression, bipolar disorder and intermittent explosive disorder disappear and don't return after gluten is eliminated from a celiac's diet provide persuasive evidence that the connection is real.
Intermittent Explosive Disorder
Intermittent explosive disorder involves much more than merely losing your temper. According to the American Psychiatric Association, this diagnosis may apply after someone has at least three episodes of flying into an uncontrollable rage out of all proportion to the precipitating incident. Classified as an impulse control disorder, IED also involves violence -- either an attempted or actual assault on a person, or the deliberate destruction of property. It typically starts in the early teens and may overlap with other psychiatric conditions such as depression and bipolar disorder. According to a study published in the June 2006 "Archives of General Psychiatry," more than 15 million Americans may suffer from IED.
A series of studies from Finland examined the connection between untreated celiac disease and psychiatric disorders, including IED. A paper published in the August 2002 "Psychosomatics" described two adolescents who had both exhibited serious mental and behavioral disorders prior to being diagnosed with celiac disease. In addition to other symptoms of mental illness, "Tom" satisfied the diagnostic criteria for IED and "Anne" had a record of "clinically abnormal aggression." A few months after eliminating gluten from their diets, all symptoms of rage disorder had disappeared and the remission lasted two years, the length of time the teens were monitored.
The authors of the Finnish studies theorize that damage to the lining of the small intestine caused by celiac disease prevents essential nutrients from being properly absorbed, leading to disruptions in levels of the mood-regulating neurotransmitter serotonin. UK neurologist Dr. Marios Hadjivassiliou, a pioneer in the study of the effects of gluten on the brains of celiacs and gluten-sensitive people, doesn't agree with them. As he argues in a paper published in "The Lancet Neurology" in March 2010, many of the patients he treats have no gastrointestinal damage, so malabsorption of nutrients couldn't account for their neurological symptoms. However, all of these experts are in agreement that more research is needed before conclusions can be drawn.
New Treatment Coming
Dr. Alessio Fasano, director of the University of Maryland's Center for Celiac Research, believes that celiac disease shares one characteristic with most -- and perhaps even all --- other autoimmune diseases -- an unusually porous intestinal wall that allows toxins to seep into the bloodstream, triggering an autoimmune response. As Fasano wrote in the August 2009 "Scientific American," celiacs and people with other autoimmune diseases all have abnormally high levels of the protein zonulin, which increases intestinal permeability. As of September 2011, phase 2B of clinical trials for a zonulin-inhibiting drug, larazotide acetate, were set to begin. Positive results in restoring gluten tolerance in celiacs were reported in previous phases.