Objectives: Anxiety and depression occur frequently in patients with functional gastrointestinal disorders (FGIDs), but their precise prevalence is unknown. We addressed this issue in a large cohort of adult patients and determined the underlying factors.
Methods: In total, 4,217 new outpatients attending 2 hospitals in Hamilton, Ontario, Canada completed questionnaires evaluating FGIDs and anxiety and depression (Hospital Anxiety and Depression scale). Chart review was performed in a random sample of 2,400 patients.
Results: Seventy-six percent of patients fulfilled Rome III criteria for FGIDs, but only 57% were diagnosed with FGIDs after excluding organic diseases, and the latter group was considered for the analysis. Compared with patients not meeting the criteria, prevalence of anxiety (odds ratio (OR) 2.66, 95% confidence interval (CI): 1.62-4.37) or depression (OR 2.04, 95% CI: 1.03-4.02) was increased in patients with FGIDs. The risk was comparable to patients with organic disease (anxiety: OR 2.12, 95% CI: 1.24-3.61; depression: OR 2.48, 95% CI: 1.21-5.09). The lowest prevalence was observed in asymptomatic patients (OR 1.37; 95% CI 0.58-3.23 and 0.51; 95% CI 0.10-2.48; for both conditions, respectively). The prevalence of anxiety and depression increased in a stepwise manner with the number of co-existing FGIDs and frequency and/or severity of gastrointestinal (GI) symptoms. Psychiatric comorbidity was more common in females with FGIDs compared with males (anxiety OR 1.73; 95% CI 1.35-2.28; depression OR 1.52; 95% CI 1.04-2.21). Anxiety and depression were formally diagnosed by the consulting physician in only 22% and 9% of patients, respectively.
Conclusions: Psychiatric comorbidity is common in patients referred to a secondary care center but is often unrecognized. The prevalence of both anxiety and depression is influenced by gender, presence of organic diseases, and FGIDs, and it increases with the number of coexistent FGIDs and frequency and severity of GI symptoms.