Celiac Disease (wheat gluten allergy) may increase risk for schizophrenia; gluten-free diet may decrease schizophrenia symptoms for small number of people

The link between celiac disease (a disorder in which the body has an allergic response to a gluten found in grains, leading to damage of the absorbant villi fingers that line the intestinal tract) and schizophrenia is suggestive, but questionable. If there is such a link, celiac disease certainly does not cause the symptoms of schizophrenia for more than a handful of individuals, given the low incidence of both disorders.

One large study of 7,997 Danish citizens (Eaton et al, 2004) who were admitted to health facilities with a diagnosis of schizophrenia between 1981 and 1998, found that four patients and eight parents of patients were being treated for celiac disease symptoms. The authors calculated an incidence of 1.5 cases of celiac disease per 1000 people in this population, as compared to a 0.5 incidence of celiac disease in the control population. Based on this data, the authors suggested a 3-fold increased risk of schizophrenia symptoms in an individual with celiac disease, over that of an individual in the general population (relative risk for general population is 1%).

Another article (Wei 2005) commented on the possible genetic link between celiac disease and schizophrenia (the genetic marker of celiac disease is close to the disbindin gene locus, a gene that may be linked to schizophrenia - thus the two loci may have a higher probability of being inherited together), and hypothesized that for individuals with celiac disease, the abnormal gut permeability that is characteristic of the disorder may contribute to schizophrenia symptoms by causing malnutrition (significantly decreased absorption of key vitamins and nutrients - vitamin D deficiency has been linked to schizophrenia), or by allowing greater amounts of psychosis-inducing toxins to enter the body.

It is important to note that there is a fair amount of dissent about the above conclusions. Campbell and Foley (2004) commented in a later edition of the British Journal of Medicine that the "data do not support the hypothesis" of the Danish study cited above. They believe that parents of people with schizophrenia should not be included in the total cases of celiac disease for that population. "If the parents' data are excluded from the analysis the prevalence of coeliac disease in people with new onset schizophrenia is only 0.5 per 1000, which is the same as in their control group." (Campbell and Foley, 2004). Another study (Peleg et al, 2004) examined 50 patients with schizophrenia for the presence of celiac-specific anti-endomysial antibodies, a screening mechanism for celiac disease. They found no antibodies in either the schizophrenia population or the control population (age-matched healthy individuals with no history of gastrointestinal disorder), and concluded that a link between gluten sensitivity and schizophrenia is "unlikely." However, the very small number of patients tested may not have been a large enough sample to detect a stastisically significant incidence of celiac antibodies over that of the general population. The actual prevalence of celiac disease in the general population has very wide-ranging estimates (from as common as 1:100 adults in the United States or 1:300 in some European countries, to as rare as 1:5000 - see 'Celiac Disease' in Dr. Joseph Smith Health Encyclopedia). This is due to the fact that the disorder can present with different symptoms, or "silently" (no obvious symptoms) - thus, there may be many undiagnosed cases. More information on the estimated prevalence of celiac disease in different populations and different countries can be found at American Family Physician 2005 Guidelines for Celiac Disease Screening. Most agree that celiac disease is far more common in white, or European, populations.

Helpful Actions: Although the possibility of celiac disease contributing to schizophrenia is small, it may be important to identify those few individuals for whom such a link might exist. In November, 2005 researchers reported that the longer a child is breast fed, the lower the risk of celiac disease. Breastfeeding has also been linked in research to lower risk of schizophrenia for the child. One case study (de Santis et al, 1997) of an individual with schizophrenia diagnosis reported that after the patient had been shown to have signs of celiac disease and was put on a gluten-free diet, the psychiatric symptoms regressed. Authors of the Danish cohort study likewise point out that "Removal of gluten from the diet is not dangerous or expensive and is an effective treatment for coeliac disease...An important question is the degree to which removal of gluten from the diet will alleviate symptoms in the small proportion of people with schizophrenia who screen positively for coeliac disease but do not show its classical symptoms." (Eaton et al, 2004, p. 439).

If you have schizophrenia and if celiac disease runs in your family, you may want to consider getting tested for the presence of IgA anti-endomysial and anti-tissue transglutaminase antibodies (these are protein markers that show up with specific lab tests - the sensitivity and specificity of the tests exceed 90% and 95%, respectively). If you show evidence of celiac disease, talk with your doctor about trying a gluten-free diet.

More information from the NIH on testing for and treating celiac disease

Supporting Research (a sample):



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