A new population-based, case-control study has produced additional evidence that celiac disease (gluten intolerance) is a risk factor for schizophrenia, according to an article in the February 21st issue of the British Medical Journal. Previous studies had suggested a correlation between the two disorders.

In the current study, an international team of researchers used Danish registries to identify 7,997 people older than 15 years who were admitted to a psychiatric unit for the first time between 1981 and 1998 with a diagnosis of schizophrenia.

For each case, they randomly selected 25 controls, matched by year of birth and sex, and looked for any history of celiac disease, ulcerative colitis, or Crohn's disease in psychiatric patients, controls, and the parents of both groups of people.

Investigators identified 4 patients, 5 mothers of patients, and 3 fathers of patients who were under treatment for celiac disease at the time of initial psychiatric admission. With adjustment for known risk factors for schizophrenia, the relative risk for schizophrenia in people with celiac disease was 3.2. In contrast, the relative risk for people with either ulcerative colitis or Crohn’s disease was 1.4.

The authors concluded that findings support a moderately strong risk relation between celiac disease and schizophrenia. However, they also stressed that the correlation is based on a very small proportion of cases, since both disorders are rare.