Gluten disorders, including both gluten sensitivity and celiac disease, have the potential to manifest as abnormalities of the brain caused by inflammation (Hadjivassilion et al., 2015). Gluten comes from wheat, rye, and barley and is composed of both gliadin and glutenin protein molecules and gives bread its soft and elastic characteristics which contributes to its favorability in the Western diet. In most individuals, dietary gluten stays within the intestinal tract and is easily digested. But in some individuals, gluten triggers the immune system as it passes through a more permeable intestinal wall (Sapone et al., 2012). The intolerance to gluten and subsequent immune response classically causes gastrointestinal distress and damage to the intestinal lining (Sapone et al., 2012). But it can also manifest into extraintestinal signs and symptoms such as arthritis, anemia, or psychotic disorders as the resulting inflammation is systemic even with no apparent gastrointestinal symptoms (Sapone et al, 2012).
Schizophrenic symptomology including hallucinations, paranoia, delusions, altered ability to understand reality, disorganized speech and thoughts, and suicide (Kraft & Westmann, 2009) and in a subset of the schizophrenic population can be caused by an autoimmune response to gluten (Cascella et al., 2013). A case study by Kraft and Westman (2009) of a 70 year old female with longstanding schizophrenia presented with symptoms of hallucinations, paranoia, disorganized thinking, and suicide attempts in which antipsychotic medications had been largely ineffective. She was trialed on a ketogenic diet with <20g/day carbohydrate and was instructed to avoid breads, pastas, and starches which also provided the benefit of a gluten-reduced diet. The individual had complete remission of schizophrenic manifestations within 8 days on the diet and improvement was maintained (Kraft, B. & Westman, E., 2009).
Various research studies have found an association between the prevalence of gluten disorders and neurological conditions (Lionetti et al., 2015; Hadjivassilion et al., 2015; Lachance & Mckenzie, 2014). Dohan was the first researcher to bring awareness to occurrence of schizophrenia among those with celiac disease (Dohan, 1966; Dohan, 1970), and Lionetti et al (2015) has demonstrated a connection between gluten sensitivity with psychosis and hallucinations. The prevalence of schizophrenia is experienced by 1% of the population and celiac disease effects 0.75% of the population (Cascella et al, 2011). Of the schizophrenic population, 23.1% have been found to have moderate to high levels of in immunoglobulin A (IgA), an antigliadin antibody most notable in celiac disease (Cascella et al, 2011). Gluten sensitivity in contrast to celiac disease has no apparent immunomarkers, so the associated prevalences of psychosis and gluten disorders may be even higher (Sapone et al., 2012).
An autoimmune response to gluten found in a subset of the schizophrenic population can have varying immunomarkers which complexes diagnosis (Cascella et al., 2011). Gluten autoimmune conditions are a spectrum of disorders (Sapone et al., 2012). A diagnosis for gluten sensitivity has no apparent immunomarkers, while a diagnosis of celiac disease most often has an increase in IgA but not always (Sapone et al., 2012). And gluten ataxia is more likely to have an elevation of immunoglobulin G (IgG) (Sapone et al, 2012). Other relevant antigliadin markers associated with schizophrenia are IgA against transglutaminase 2 and IgA against deamidated epitopes (Jin et al, 2010). And in most recent research, transglutaminase 6 (TG6) has been found to have a significant association with the gluten-associated neurological conditions, gluten ataxia and schizophrenia (Hadjivassilion et al., 2015; Cascella et al., 2013). At this time, there doesn’t appear to be any singular laboratory test with high specificity to diagnosis gluten-affected schizophrenia.
The Evidence Analysis Library of the Academy of Nutrition & Dietetics does not currently remark specifically on gluten and schizophrenia (Evidence Analysis Library, n.d.). Additionally, a diagnosis and intervention for gluten-related schizophrenia is unaddressed by UpToDate, a commonly used resource by practitioners in patient care. Unless clinical dietitians within the field of psychiatry have a personal interest and awareness of the connection between schizophrenia and gluten, the intervention thereof is nonexistent. Although there are several recent observational studies on the association between schizophrenia and gluten disorders, there is a great lack of experimental trials within the last 3 decades. Even still, historical experimental trials between 1965 and 1986 may provide much value for the field of nutrition and mental health and can be found here.
References
Cascella, N., Kryszak, D., Bhatti, B., Gregory, P., Kelly, D., McEvoy, J., Fasano, A., Eaton, W. (2011). Prevalence of celiac disease and gluten sensitivity in the United States clinical antipsychotic trials of intervention effectiveness study population. Schizophrenia Bulletin. Volume 37. pp 94–100. doi: /10.1093/schbul/sbp055
Cascella, N., Santora, D., Gregory, P., Kelly, D., Fasano, A., & Eaton, W. (2013). Increased prevalence of transglutaminase 6 antibodies in sera from schizophrenia patients. Schizophrenia Bulletin, 39(4), 867-871. doi:10.1093/SCHBUL/SBS064
Dohan, F. C. (1966). Cereals And Schizophrenia Data And Hypothesis. Acta Psychiatrica Scandinavica, 42(2), 125-152. doi:10.1111/j.1600-0447.1966.tb01920.x
Dohan, F. (1970). Cœliac Disease And Schizophrenia. The Lancet, 295(7652), 897-898. doi:10.1016/s0140-6736(70)91729-0
Dohan, F., Grasberger, J., Lowell, F., Johnston, H., Jr, & Arbegast, A. (1969). Relapsed schizophrenics: more rapid improvement on a milk- and cereal-free diet. British Journal of Psychiatry: The Journal Of Mental Science, 115(522), 595–596.
Evidence Analysis Library. (n.d.). A - Z Index. Retrieved November 20, 2018, from www.andeal.org/a_z_index.cfm?web_menu_id=5
Kraft, B. & Westman, E. (2009). Schizophrenia, gluten, and low-carbohydrate, ketogenic diets: a case report and review of the literature. Nutrition & Metabolism, 6(1), 10-10. doi:10.1186/1743-7075-6-10
Lionetti, E., Leonardi, S., Franzonello, C., Mancardi, M., Ruggieri, M., & Catassi, C. (2015). Gluten Psychosis: Confirmation of a New Clinical Entity. Nutrients, 7(7), 5532-5539. doi:10.3390/nu7075235
Sapone, Bai, Ciacci, Dolinsek, Green, Hadjivassiliou, Kaukinen, Rostami, Sanders, Schumann, Ullrich, Villalta, Volta, Catassi, Fasano. (2012). Spectrum of gluten-related disorders: consensus on new nomenclature and classification. BMC Medicine, 10(13), 1741-7015.