More patients receive a diagnosis of a mood or anxiety disorder before diagnosis of a functional gastrointestinal disorder (FGID), researchers report in the July issue of Clinical Gastroenterology and Hepatology. The findings indicate opportunities for prevention and support the role of adverse socioeconomic factors in development of FGIDs in patients with psychological disorders.
Functional gut conditions are not associated with any identifiable pathology, but have been associated with anxiety and depression. Understanding the interactions between brain and gastrointestinal disorders requires analysis of the order of disease onset.
Michael P. Jones et al analyzed data from 2 independent studies to determine the proportion of individuals with diagnoses of functional gastrointestinal disorders (FGIDs) before diagnoses of mood or anxiety disorders (gut to brain), and vice versa (brain to gut).
They found that among the 4966 health-care seekers in the UK, 3279 patients were diagnosed with a mood or anxiety disorder before an FGID (ratio of 2:1). This ratio increased with socioeconomic disadvantage.
The time period between diagnosis of mood or anxiety disorder and FGID was longer (median, 3.5 years) than time period between diagnosis of an FGID and a mood or anxiety disorder (median, 1.8 years, see figure).
Among non–heath care seekers (the Australian population study), equal proportions were diagnosed with a mood or anxiety disorder before vs after an FGID. However, anxiety, depression, and neuroticism increased odds for a brain-gut order of incidence.
The authors say that it is possible that some of these gastrointestinal disorders could be caused by central nervous system medications used to treat psychiatric disorders or other indications, although these would be unlikely to cause irritable bowel syndrome (IBS) or functional dyspepsia.
Jones et al state that their findings are consistent with data from studies of the influence of childhood abuse on subsequent FGIDs in adults. Childhood abuse has been associated with anxiety, indicating a chronic rather than acute process in the brain to gut direction.
In contrast, among individuals with an FGID, mood or anxiety disorders generally develop in about half the time of brain-gut disorders—the influence of FGID symptoms on mood or anxiety is relatively rapid.
Jones et al say that the long latency between onset of mood or anxiety disorder and FGID offers an opportunity to prevent the onset of gastrointestinal symptoms that affect quality of life.
One limitation of the study is that the true order of incidence could not be completely established. The authors attempted to add rigor to disease definition by requiring a recorded diagnosis and prescription of a potentially relevant medication.
Strengths of this study include the large sample size and the fact that the patients included were more representative of patients with FGID in general, compared those in tertiary care.
These studies provide insights from health care seekers and from the general population. Although there are important differences between these populations, a comparison of their findings provides information on the generalizability of the findings.