As early as 1953, Loretta Bender observed a higher incidence of celiac disease among individuals with schizophrenia compared with the general population. Building on this observation, Curtis Dohan noted that during the Second World War, cereal consumption declined due to rationing. During this same period, hospitalizations for schizophrenia decreased, even as hospitalizations for other psychiatric disorders increased. These observations led Dohan to hypothesize a possible relationship between cereal grains and schizophrenia.
In 1969, Dohan conducted a double-blind study in which patients with schizophrenia followed a cereal- and milk-free diet. The study reported clinical improvements in some patients, suggesting that dietary factors might influence symptoms in at least a subset of individuals.
Further investigation appeared in the American Journal of Psychiatry (November 1978; Volume 135, Issue 11, Pages 1417–1418). This study examined 16 patients with schizophrenia, with a mean age of 38 years and an average hospitalization duration of nine years. Participants were given gluten in gradually increasing doses, starting at 30 grams per day and increasing by 5 grams each week over a three-week period. Patients were evaluated weekly using the Brief Psychiatric Rating Scale, and additional clinical observations were recorded by ward staff using the Missouri Mental Status Examination Scale.
Increased gluten intake was associated with significant clinical changes. One patient experienced severe symptom regression, requiring discontinuation of gluten and treatment with intramuscular medication. Two patients showed notable improvement. One individual, who had been hospitalized for 13 years with chronic schizophrenia, improved sufficiently to be discharged from the hospital.
These early findings contributed to ongoing discussion about the potential relationship between gluten sensitivity, celiac disease, and psychiatric symptoms, while also highlighting the need for further controlled research to clarify which patients, if any, may be affected by dietary factors.
