The relation of ulcerative colitis to psychiatric factors: a review of findings and methods.

The authors reviewed all known English-language literature on the association between psychiatric factors and ulcerative colitis to ascertain the evidence for such an association and evaluate the methods used in these studies. Most of the 138 studies contained serious flaws in research design, such as lack of control subjects, unspecified manner of data collection, and absence of diagnostic criteria. Analysis revealed that methodological flaws were significantly related to the finding of a positive association between psychiatric factors and ulcerative colitis. Seven studies represented solid systematic investigation, and all seven failed to find such an association.