METHODS
Literature Search and Grading the Articles for Quality of Evidence
The project started in September 2011 by formulating 9 clinical questions. Seven questions were chosen based on the Dutch guidelines for functional constipation (6). In addition, 2 new questions were added to the present guidelines: questions 5 and 8. After the questions were formulated, the guidelines committee was subdivided into subgroups that dealt with each question separately. Questions 1 and 2 were answered based on expert opinions and earlier published guidelines (5–9). Questions 3 to 9 were answered using the results of systematic literature searches. Systematic literature searches were performed by a clinical librarian from inception to October 2011. The Embase, MEDLINE, Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Clinical Trials, and PsychInfo databases were searched.