BACKGROUND: Functional gastrointestinal disorders, such as irritable bowel syndrome and nonulcer dyspepsia, are difficult for primary care physicians to treat. These conditions result in frequent referrals and are frustrating for both patients and physicians. Because of their usefulness for other painful chronic conditions, antidepressants have been suggested as a therapeutic alternative.
POPULATION STUDIED: This meta-analysis included 12 studies of the use of antidepressant medications for the treatment of functional gastrointestinal disorders. Most only included adults, with a range of mean ages of 33 to 48 years.
STUDY DESIGN AND VALIDITY: The authors obtained articles through a MEDLINE, PsycLIT, and EMBASE search covering 1966 through 1998. They also searched the Cochrane Controlled Trials Register and Federal Research in Progress to identify unpublished research. Of 90 articles, 12 met their inclusion criteria. The quality of each study was formally evaluated using a standard instrument. In a meta-analysis, the validity of the study depends on the validity of the individual studies, as well as the authors’ ability to group the data in a reasonable fashion. Because each study was listed in a table, we are able to assess quality independent of the meta-analysis.
OUTCOMES MEASURED: The primary outcome was a subjective decrease in gastrointestinal symptoms.
RESULTS: Most of the studies were of low quality. Only 2 studies had a quality rating of 7 (out of 8), and most were in the 2 to 4 range. The authors acknowledge the difficulty of blinding patients in these studies because of the noticeable side effects of most of the drugs tested. In addition, the size of the individual studies was small (only 1 included more than 100 patients), and the duration of follow-up was usually only 4 to 8 weeks. However, the findings were consistent. All studies demonstrated an improvement in both abdominal pain scores and the likelihood of overall improvement in gastrointestinal symptoms among patients treated with antidepressants when compared with placebo. The authors estimate that 3 patients have to be treated for 1 to benefit, which would compare favorably with other widely used interventions for this and other problems. Improvements were seen with both tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs).
The use of tricyclic antidepressants and SSRIs for the treatment of functional gastrointestinal disorders can be of benefit to some patients. Given the difficulty of treating these disorders, the relative safety of the doses studied, and the potential benefit in symptom relief and reduction in referrals, antidepressants are a reasonable alternative despite the weakness of the studies. More studies of higher quality are needed to definitively answer this question and to assist in the selection of the best class of antidepressants.