The current study evaluated the prevalence of depressive and anxiety disorders among mainland Chinese outpatients visiting GI clinics, regardless of confirmed GI diagnosis. The adjusted current prevalence of depressive disorders, anxiety disorders, and comorbid disorders was 14.39%, 9.42% and 4.66%, respectively.
It is well recognized that depressive and anxiety disorders impair life quality and cause a heavy disease burden[35-38
]. Nevertheless, more than half of patients with depression or anxiety visit non-psychiatric departments, especially the GI department, for somatic symptoms[20,21,39,40
]. However, most general physicians are not appropriately trained in psychiatry and cannot diagnose or treat depressive and anxiety disorders. Thus, GI physicians tend towards a low detection rate[41-43
]. It is meaningful to investigate overall prevalence of depressive and/or anxiety disorders in GI outpatients to understand the actual patient population involved and the importance of diagnosing such disorders.
According to our knowledge, this is the largest study investigating the prevalence of depressive and anxiety disorders in GI outpatients from tertiary general hospitals in mainland China. The reliability of the current prevalence figures was assured by the use of experienced psychiatrists administering a structured diagnostic instrument. The tertiary general hospitals enrolled in this study were distributed in north (Beijing), east (Shanghai), south (Guangzhou), west (Chengdu) and central (Changsha) China, and represent the majority of national tertiary general hospitals. In addition, the DSM-IV-based MINI was used by experienced psychiatrists to produce accurate and consistent diagnoses. Finally, the study was carried out in two stages, preliminary screening and diagnostic interview.
Prevalence of depressive disorders and/or anxiety disorders in general hospitals or primary care
The overall prevalence figures of depressive disorders and/or anxiety disorders in general medical care have been reported previously[15,44
]. The current adjusted prevalence of depressive disorders in our study was 14.39%. However, this value was 19.5% in a meta-analysis of primary care patients in ten countries[41
]. The current adjusted prevalence of anxiety disorders reported in our study was 9.42%, which was lower than the 19.0% prevalence reported among Belgian outpatients in 86 general practices[45
] and the 19.5% prevalence reported in 15 United States general medical care centers[15
]. These apparent discrepancies may be a result of subjects in the previous studies being from primary care and the Primary Care Evaluation of Mental Disorders being used for diagnosis.
Furthermore, other previous domestic investigations have reported varying prevalence of depressive disorders and anxiety disorders. Qin et al[46
] reported prevalence of 11.01% for depressive disorders in internal medical outpatients from 23 general hospitals in Shenyang. The prevalence of depression was 12.5% in family practices in Taiwan[25
], while the prevalence of anxiety disorders was 11.61% in six tertiary general hospitals in Shenyang[42
]. Generally speaking, these different results were due to variances in subjects and investigation instruments. The prevalence of depressive disorders and/or anxiety disorders in our study and other domestic studies are lower than results from abroad, which may relate to differences in ethnicity or culture[47,48
The 1.25% current prevalence of dysthymia, the third top depressive disorder in our study, was higher than the 0.6% prevalence in Shanghai subjects reported by the WHO[43
] in 1990, but was similar to the 2.1% mean prevalence for all international sites that participated in the research and the 2.8% prevalence of dysthymia in the study of Qin et al[46
]. It was lower than the 12.6% prevalence of dysthymia among outpatients from 86 general practices in Belgium[45
It is well-known that comorbidity of depressive disorders and anxiety disorders can exacerbate symptoms, and co-occurrence of anxiety is an independent risk factor of suicide among depressive patients[35,49
]. In the current study, anxiety disorders were comorbid in 32.6% of depressive individuals. This comorbid proportion in depressive patients was found to be 68.9% in a study conducted in 15 centers of China[50
], and 50.6% in the United States[51
]. It is a common phenomenon that depressive disorders and anxiety disorders are in comorbidity among outpatients in general medical care.
Detection rate by physicians in general hospitals or primary care
Detection rate in this study was 4.14%, similar to the 4% reported for Shenyang[42,46
]. A United States-based study of outpatients with GI symptoms revealed that 52% of anxious patients and 26% of depressive patients were recognized by gastroenterologists[16
]. Family practices surveyed in Taiwan[25
] indicated that the recognition rate of depression disorders was 12.5%, and that of general anxiety disorder was 8.0%. Prevalence of depression disorders in internal medicine inpatients was 26.9% and only 40% of these patients received antidepressant treatment[52
]. Another MINI-based study of internal medicine inpatients revealed that prevalence of depressive disorders was 26%, and 43.8% of them were treated with antidepressants[53
]. A meta-analysis conducted by Mitchell et al[41
] indicated that correct diagnosis rate of clinicians was 47.3%-50.1%. The remarkable difference in detection rate between other investigations and ours suggests the urgent need to improve the diagnosing rates in mainland China.
Meanwhile, comorbid disorders deserve great attention due to their significant correlation to suicide risk. Current prevalence of depressive disorders with suicidal problems was 3.91% in our study, suggesting that over a quarter of patients with depressive disorders were at suicide risk, while only 4.48% of those patients were recognized. Carson et al[54
] indicated that morbidity of major depression with suicide ideation was 29.9%, while its recognition rate by physicians was 58%. Moreover, prevalence of depression and/or anxiety disorders in our study was higher in females than in males, which is consistent with results in Qin’s study[42,46
], and reminds physicians to pay more attention to female outpatients with mood problems.
Discrepancies of prevalence and detection rate between our study and previous studies likely reflect the limitations of methodology, which require significant effort to be overcome in subsequent research.
These findings confirm the high prevalence of depressive and anxiety disorders and disappointing detection and treatment rate in the GI departments, and highlight the particular challenge posed by the contrasts between these two rates. Although all 13 tertiary hospitals represent the top general hospitals in China, low recognition and treatment rates raise significant concerns and indicate the need to improve the physician’s abilities to diagnose and identify emotional disorders in GI patients.
Several potential explanations exist for the high prevalence of depressive and anxiety disorders and low detection rate in GI outpatients. Physicians are less specialized than psychiatrists in recognizing mental disorders correctly. Furthermore, culture may limit physicians’ abilities in this regard. In the Chinese traditional culture, social and cognitive processes or mental status are closely related, which contributes to interpreting emotional distress and anxiety as social or ethical problems rather than mental disorders. Somatic symptoms can also serve as cultural idioms of depressive emotion[55-57
]. Depressed or anxious people are inclined to experience physical symptoms, masking the underlying mental disorder[39
]. In addition, there is a distorted cognition of mental disorders. It is common to consider depressive individuals as having no self-control and weak. Jorm et al[58
] reported that around a quarter of Australian adults consider antidepressants as harmful to suicidal depressive patients, who are more likely to reject relevant treatments, including psychotherapy. Finally, the established stigma of mental disorders causes hiding of emotional problems and rationalization to resist therapy. Dramatic reports in the mainstream media of aggressive behavior by mental disorder sufferers prejudice both patients and physicians against the disorder[59-61
Previous studies have proven that depressive and anxiety disorders influence prognosis of physical diseases, raise medical risk, and increase economic burden[62,63
]. However, appropriate treatment does benefit recovery from physical disease and maintenance of social function[64-66
]. Therefore, clinicians should improve their ability to diagnose depression and anxiety, especially in patients with complaints of unexplained GI symptoms.
Several limitations exist in the current study. Firstly, excluding outpatients who could not complete the investigation due to severe physical or mental dysfunction may have biased the results since severity of physical symptoms is positively related to depression, anxiety or other mental problems[67,68
]. Secondly, the 385 missing cases (due to busy schedules and denial of mental issues) from the diagnostic interview accounted for 19.3% of the total. There were no statistically significant differences between missing and follow-up cases in sex (χ2
= 0.066, P
= 0.797) or age (t
= -0.860, P
= 0.390). Although statistical adjustment was performed, representation of the sample in the study may have been impacted.