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- MATERIALS AND METHODS
Most studies of depression and inflammatory bowel disease (IBD) have been drawn from clinical populations or from samples selected from the membership of Crohn's and ulcerative colitis community organizations. This study determined the prevalence and correlates of depression in people with IBD or a similar bowel disorder from 2 nationally representative Canadian surveys. In the Canadian Community Health Survey, conducted in 2000 through 2001, there were 3076 respondents who reported that they had “a bowel disorder such as Crohn's disease or colitis” that had lasted ≥6 months and had been diagnosed by a health professional. The National Population Health Survey, conducted from 1996 through 1997, had 1438 respondents who reported that they had such a condition. Within each subsample, bivariate analyses were conducted to compare the depressed and nondepressed individuals. Logistic regression analyses also were conducted using the Canadian Community Health Survey 1.1 data set. The 12-month period prevalence of depression among individuals with IBD and similar bowel disorders was comparable in the 2 data sets (16.3% and 14.7%). Depression rates were higher among female respondents, those without partners, younger respondents, those who reported greater pain, and those who had functional limitations. Seventeen percent of depressed respondents had considered suicide in the past 12 months; an additional 30% had considered suicide at an earlier time. Only 40% of depressed individuals were using antidepressants. Individuals with IBD and similar bowel disorders experience rates of depression that are triple those of the general population. It is important for clinicians to assess depression and suicidal ideation among their patients with active IBD symptoms, particularly among those reporting moderate to severe pain.
Although inflammatory bowel disease (IBD) can occur at any age, it is diagnosed most frequently in the second and third decades of life.1,2 At a time when young people are separating from their family of origin, pursuing educational and career goals, and starting their own families, they are forced back into the dependency of illness. Moreover, the chronic relapsing nature of IBD, the need for debilitating treatments, and its threats to body image and social and sexual functioning can seriously impair psychological well-being and quality of life.3,4 It is therefore understandable that, like other chronically ill patient groups,5–10 studies have reported a higher prevalence of psychosocial distress in people with IBD than in the general population.11–13 In nonpediatric IBD populations, the literature specifically examining depression is limited,12,14–16 but depression has been studied more extensively as a component of psychological disturbance, mood, and health-related quality of life (HRQOL)17–27 or as a comparator for alexithymia.13 Not surprisingly, higher levels of depression are associated with symptom severity,14,17,21-23,25,28 poorer quality of life,3,21,23,29 and lower life satisfaction scores.4 Stressful events, particularly when patients have low levels of social support, are associated with higher levels of psychological distress, including depression.28 Other studies have found that the presence of a psychological disorder in IBD is associated with poor HRQOL21,22,26,27 and self-perceived functional disability,27 regardless of symptom severity. A recent synthesis of the literature indicates that depression may exacerbate Crohn's disease.30 Depression in IBD patients also is associated with more visits to both gastroenterologists and primary care physicians.19,20
Most studies that explore the relationships among IBD, HRQOL, and psychological distress, including depression, have been drawn from clinical populations that tend to be sicker than community populations or from samples selected from the membership of Crohn's and ulcerative colitis organizations. The data reported in this study are from large, nationally representative samples. The question in both surveys asked whether respondents had been diagnosed by a health professional as having a bowel disorder such as Crohn's disease or colitis. Because of the wording of the question, it is possible that the sample includes some individuals with a bowel disorder that is not IBD. However, because these are nationally representative studies, they may be helpful in understanding the nature and extent of depression in the broader spectrum of individuals living with IBD and similar bowel disorders in the community.
- Top of page
- MATERIALS AND METHODS
The prevalence rates of depression among respondents with IBD or similar bowel disorders were 16.3% in the CCHS and 14.7% in the NPHS. Bivariate analyses in both data sets yielded similar demographic profiles of depressed respondents with IBD or similar bowel disorders (see Table 1). Depressed respondents were younger and were more likely to be female, to be born in Canada, to have graduated from high school, and to have experienced food insecurity. Although in the CCHS data set depressed respondents had lower mean incomes than nondepressed respondents, the 2 groups had comparable incomes in the NPHS.
Table Table 1. Demographic Characteristics of IBD Patients by Dichotomized Depression Index (CCHS and NPHS)
| ||% Within Not Depressed (n = 2575; 83.7%)||% Withi Depressed (n = 501; (16.3%)||Total (n = 3076;* (100%)||P||% Within Not Depressed (n = 1227; 85.3%)||% Within Depressed (n = 211; 14.7%)||Total (n = 1438;0 100%)||P|
|20Y29||12.0||16.4||12.7|| ||13.8||16.7||14.2|| |
|30Y39||14.3||22.6||15.6|| ||18.6||31.6||20.5|| |
|40Y49||20.5||29.3||21.9|| ||20.3||25.8||21.1|| |
|50Y59||18.9||18.8||18.9|| ||12.0||13.4||12.2|| |
|60Y69||12.3||6.4||11.3|| ||12.7||5.7||11.7|| |
|70Y79||12.8||3.8||11.3|| ||11.6||3.3||10.4|| |
|Q80+||6.5||1.2||5.6|| ||7.8||0.5||6.7|| |
|Mean age,1 yr||50.5||43.2|| ||G0.001||49.5||41.1|| ||G0.001|
| ||(SD = 17.9)||(SD = 13.9)|| || ||(SD = 19.3)||(SD = 14.1)|| || |
| ||(n = 2575)||n = 501|| || ||(n = 1227)||(n = 210)|| || |
|Not a high school||27.0||19.8||25.9||0.001||28.7||21.4||27.6||0.03|
|Mean income,1||48,662||44,605|| ||G0.01||35,981||36,811|| ||0.65|
|Canadian $||(SD = 27,588)||(SD = 27,375)|| || ||(SD = 23,647)||(SD = 22,169)|| || |
| ||(n = 2306)||(n = 462)|| || ||(n = 1029)||(n = 189)|| || |
|Food insecurity||17.8||37.8||21.1||G0.001|| || || || |
|Household ran out|| ||NA|| || ||12.0||22.4||13.5||G0.001|
|of money to buy food|
|Has someone|| ||NA|| || ||90.7||87.1||90.2||0.11|
|to confide in|
The health-related characteristics of depressed respondents with IBD or a similar bowel disorder also were comparable in both data sets (see Table 2). Depressed respondents were more likely to report poor or fair health, to identify ADL and IADL limitations, and to have ≥2 chronic conditions. They experienced a higher likelihood of having asthma, chronic bronchitis, back problems excluding arthritis, and migraines, and they were less likely to have cataracts. The diseases of fibromyalgia and chronic fatigue syndrome also were associated with depression in the CCHS. These diseases were not studied in the NPHS. Those reporting high levels of pain (NPHS) and those whose activities were restricted by pain (CCHS) were more likely to be depressed.
Table Table 2. Health-related Characteristics of IBD Patients by Dichotomized Depression Index (CCHS and NPHS)
|% Within Not Depressed (n = 2575; 83.7%)||% Within Depressed (n = 501; 16.3%)||Total (n = 3076;* 100%)||P||% Within Not Depressed (n = 1227; 85.3%)||% Within Depressed (n = 211; 14.7%)||Total (n = 1438;0 100%)||P|
|Self-reported health status|
|Excellent/very||67.7||47.8||64.4|| ||69.5||52.4||67.0|| |
|ADL limitations||8.8||12.2||9.3||0.0|| ||NA|| ||0.02|
|IADL limitations||20.6||33.8||22.8||G0.001|| || || || |
|Activities prevented||35.1||58.4||38.9||G0.001|| ||NA|| || |
|Activity limitations|| ||NA|| || ||48.4||72.0||51.8||G0.001|
|(whether or not|
|caused by pain)|
|Level of pain|
|No pain|| ||NA|| || ||61.2||48.6||59.3||G0.001|
|Mild pain|| || || || ||9.2||10.0||9.3|| |
|Moderate pain|| || || || ||21.3||21.0||21.2|| |
|Severe pain|| || || || ||8.3||20.5||10.1|| |
|Number of chronic conditions|
|Has IBD and no other||24.6 (n = 725)||20.2||23.9||G0.001||14.2||9.6||13.5||0.03|
|Has IBD and 1||28.0 (n = 798)||17.8||26.3|| ||21.2||16.3||20.5|| |
|Has IBD and Q2||47.4 (n = 1510)||62.0||49.8|| ||64.6||74.0||66.0|| |
|Prevalence of other chronic||conditions|
|Arthritis or rheumatism||38.6||42.3||39.2||0.12||38.1||35.2||37.7||0.43|
|Suffers from the||2.3||1.4||2.1||0.21||3.8||1.0||3.4||0.03|
|effects of stroke|
|Chronic fatigue syndrome||2.3||11.6||3.8||G0.001|
A separate analysis was conducted to explore the interaction between social support, pain, and depressed status (see Figure 1). Because the social support data were available only for the complete sample of the NPHS, not the CCHS, this subanalysis was restricted to the NPHS data set. Respondents with IBD or a similar bowel disorder who experienced moderate or severe pain were more likely to be depressed if they did not have a confidant (see Figure 1; P < 0.05). In contrast, the presence of a confidant was not a significant factor in the rates of depression for those who were not in pain (P = 0.35).
Figure FIGURE 1.. Percent of individuals with depression by level of pain and presence of a confidant (NPHS 1996–1997; n = 1421 individuals with IBD or a similar bowel disorder).
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A substantial minority of depressed respondents in both the CCHS and NPHS had not consulted a mental health professional in the past 12 months (47.6% and 37.3%, respectively; see Table 3). Depressed respondents were more likely to consult their family doctor about mental health issues than any other health professionals. In both surveys, depressed respondents with IBD or a similar bowel disorder were more likely to report that during the previous 12 months they felt they had needed health care but did not receive it. However, the CCHS depressed respondents were twice as likely to report unmet healthcare needs as the depressed respondents in the NPHS sample.
Table Table 3. Healthcare Utilization Characteristics of IBD Patients by Dichotomized Depression Index (CCHS and NPHS)
| ||% Within Not Depressed (n = 2575; 83.7%)||% Within Depressed (n = 501; 16.3%)||Total (n = 3076;* (100%)||P||% Within Not Depressed (n = 1227; 85.3%)||% Within Depressed (n = 211; 14.7%)||Total (n = 1438;† 100%)||P|
|Healthcare utilization characteristics|| || || || || || || |
|Consulted mental health professional||11.1||52.4||17.9||<0.001|| || || || |
|Mental health visits, n|| || || || || || || || |
|1–3||5.8||21.4||8.4|| ||4.5||13.4||5.8|| |
|4–12||5.3||31.0||9.5|| ||5.6||49.3||11.9|| |
|Consulted mental health professionalYfamily doctor||6.0||26.9||9.4||G0.001|| || || || |
|Consulted mental health professional-psychiatrist||2.3||12.8||4.0||<0.001|| || || || |
|Consulted mental health professional-psychologist||1.7||12.4||3.5||<0.001|| || || || |
|Consulted social worker for mental health use||2.1||12.4||3.8||<0.001|| || || || |
|Attended self-help group||4.7||13.2||6.1||<0.001||5.6||13.8||6.8||<0.001|
|Felt that health care was needed but did not receive it||22.4||41.1||25.4||<0.001||11.3||21.4||12.7||<0.001|
|Drug use|| || || || || || || || |
|Used antidepressants in the past month‡||7.2 (n = 67)||26.2 (n = 44)||10.1||<0.001||9.2||40.2||13.7||<0.001|
|Used tranquilizers in the past month|| ||NA|| || ||6.3||29.2||9.6||<0.001|
|Used sleeping pills in the past month|| ||NA|| || ||7.6||21.9||9.7||<0.001|
The logistic regression analyses of individuals with IBD and similar disorders in the CCHS indicate that the odds of depression were higher among female responders, the unmarried, and high school graduates (see Table 4). The highest odds of depression were among those 20 to 49 years of age. Food insecurity, a measure of extreme poverty, was associated with increased odds of depression. Those in fair or poor health had almost twice the odds of depression as those who were in good to excellent health. Those with IADL limitations had higher odds of depression. Individuals who had activities prevented by pain were more likely to be depressed. In contrast to the bivariate findings, when other characteristics were controlled in the equation, the presence of ADL limitations and the number of chronic diseases were not significantly associated with depression.
Table Table 4. Logistic Regression Analysis Predicting Depression Among IBD Patients: CCHS
|Variables Confidence||Odds Ratio (95% Interval)||P|
|Demographic characteristics|| || |
|Age by decade, yr|| || |
|Q80 (Reference)|| || |
|Immigrant status|| || |
|Reference: Canadian-born||0.72 (0.50–1.04)||0.08|
|Marital status|| || |
|Unmarried (never married,||1.78 (1.39–2.28)||<0.001|
|separated, divorced)|| || |
|Education|| || |
|Secondary school||1.35 (1.01–1.81)||0.045|
|graduation and higher|| || |
|Reference: less than secondary||school graduation|| |
|Race|| || |
|Reference: visible minority|| || |
|Derived income adequacy||category|| |
|Middle income||1.42 (0.99–2.04)||0.056|
|High income||1.27 (0.89–1.83)||0.21|
|Reference, low income|| || |
|Food insecurity|| || |
|Reference: no||1.55 (1.19–2.01)||0.001|
|Health-related characteristics|| || |
|Self-reported health status|| || |
|Fair/poor health||1.93 (1.48–2.50)||<0.001|
|Reference: excellent/very||good/good health|| |
|Chronic conditions|| || |
|Has IBD and 1 additional||0.83 (0.59–1.17)||0.291|
|chronic condition|| || |
|Has IBD and Q2 additional||1.31 (0.95–1.80)||0.099|
|chronic conditions|| || |
|Reference: has IBD and no||other chronic||conditions|
|Activity limitations|| || |
|ADL limitations||0.71 (0.47–1.09)||0.119|
|IADL limitations||1.49 (1.10–2.03)||0.011|
|Reference: no ADL/IADL||limitations|| |
|Activities prevented by pain|| || |
|Reference: no||1.71 (1.32–2.23)||<0.001|
|n = 2689.|| || |
Suicidal ideation was explored in a subsample of the CCHS. Seventeen percent of depressed respondents had considered suicide in the past 12 months. An additional 30% had considered suicide earlier in their lifetime. When the sample was restricted to those individuals who were currently depressed, several factors were associated with suicidal ideation (P < 0.05): female responders were more likely than male responders to have ever considered suicide (50% vs 31%). Half of those with at least a high school education reported suicidal ideation compared with one third of those who had not graduated from high school. Individuals 30 to 59 years of age had higher rates than those respondents who were younger and those who were older. Two thirds of the lowest-income group had considered suicide in contrast to 40% of the highest-income group.
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- MATERIALS AND METHODS
The rates of depression for respondents with IBD or similar disorders in the CCHS sample (16.3%) and the NPHS sample (14.7%) were comparable. These rates were much higher than in the general Canadian population, in which an estimated 5.6% have a 12-month prevalence of major depression.36 In the study of depression in a clinical sample of IBD patients by Walker et al,27 prevalence rates ranged up to 35%. The lower rates in this study are not surprising because the CCHS and NPHS community samples include individuals in remission, whereas Walker and his colleagues recruited their sample from a tertiary care center where the clients were more likely to have acute symptoms. The rates of depression among those with IBD and similar disorders in this study appear to be comparable to community-based samples of individuals with type 1 diabetes (15.2%),40 rheumatoid arthritis (15%),41 and older people with cancer (15%)42; lower than those with type 2 diabetes (19.0%)40 and chronic back pain (19.8%)43; but higher than those of people with heart failure (11%).44 In keeping with trends in the general population, the prevalence of depression was higher among women and younger respondents and lower among those who were married.36,45 Previous studies of clinical populations reported that women with IBD were more likely to be depressed than men2,17 and that IBD symptom severity, which itself correlates with depression, was elevated in women.46,47 Similar to studies of immigrant mental health in the United States48 and Canada,49 immigrants were less likely to be depressed.
In the present study, respondents ≥50 years of age had lower odds of depression than did those 20 to 49 years of age. Casellas and colleagues17 found that longer disease duration in IBD patients was associated with a significantly better HRQOL. Over time, adaptation to illness may lessen the perceived burden of disease and improve well-being. Because IBD often is diagnosed at a young age, the interruption of normal developmental tasks creates additional stressors in this population. Illness flare-ups, side effects of treatment, and the chronicity of pain and debility can tax personal resilience and can disrupt educational plans, careers, relationships, and raising families. These factors may contribute to a greater likelihood of depression in the younger IBD population. Similar to IBD, major depressive disorder often has an early age of onset.50 As a consequence, there may be intersecting risk factors that potentiate the likelihood of depression in younger IBD patients.
Surprisingly, in the logistic regression analysis of the CCHS sample, respondents who had a secondary education or more had 35% higher odds of being depressed than those who did not complete high school. This is in contrast to other research in which people in higher educational categories report a lower prevalence of depression.50,51 One can speculate that for people with higher education, the chronic relapsing nature of IBD interferes with the ability to keep up with professional, economic, and social demands, all of which can be sources of increased stress.
In addition, unlike other studies,50–52 income adequacy did not quite reach the level of significance in the multivariate analysis. However, a measure of extreme poverty-whether in the past year the respondent ever had insufficient money to buy food-was highly associated with depression. In the general population, food insecurity also has been associated with depression.53,54 Under such circumstances, coping with IBD would make a difficult existence even more stressful. Moreover, food insecurity may give rise to malnutrition. Addolorato et al14 found a significant relationship between depression and nutritional status in IBD patients.
Our findings shed some light on the inverse relationship between social support and depression.55–57 For example, respondents with IBD who were not with a partner (single, separated, divorced) had greater odds of being depressed than those who were married. Moreover, social support appears to play a more substantial role in the context of pain. Clinical implications include the expansion of mutual aid support groups for the IBD population and their families.58
Understandably, respondents in the CCHS sample whose activities were limited by pain and respondents in the NPHS who were in severe pain were much more likely to be depressed. The finding about the ameliorating interaction between the presence of a confidant and pain and depression is in keeping with the findings of the study by Sewitch et al,28 which correlated social support and decreased vulnerability to psychological distress in IBD patients.
People reporting poor or fair health were much more likely to be depressed. This agrees with the findings of Guthrie et al,21 who report that depression is independently associated with general health perceptions, and with Casellas and colleagues,17 who found that the need for hospitalization and the presence of clinical relapse were associated with social impairment and emotional function. Nabalamba et al59 reported that in the past 2 decades the percentage of hospitalizations in Canada for IBD has actually risen. Given the association of depression with poor health and hospitalization, it follows that hospitalized IBD patients could benefit from careful screening of mood. Another study19 found that depression correlated with visits to the gastroenterologist and that current poor emotional functioning was associated with both gastroenterologist and general practitioner visits. In a large Norwegian population study of depression, Stordal et al60 found that somatic symptoms had more influence on depression at a younger age (30–49 years) and that the most frequently reported symptoms were gastrointestinal complaints. Similarly, Barkow and colleagues61 reported that abdominal pain was 1 factor associated with persistent depression. Because gastrointestinal symptoms appear to be a risk factor for depression and its persistence in non-IBD populations, assessment of depression becomes even more pertinent in people with IBD and similar bowel disorders.
Respondents in the CCHS also were more likely to be depressed if they experienced limitations in their IADL but not in their basic ADL. People with IBD who have limitations in ADL (e.g., needing personal care, help transferring) are more likely to be acutely ill; therefore, the need for assistance may be viewed as a temporary situation related to a flare-up or hospitalization. However, IADL limitations that necessitate help with preparing meals and shopping for groceries and banking imply that individuals are incapable of carrying out their normal roles in the community. This latter situation may increase the risk of depression. Consistent with this finding, Guthrie et al21 reported that disease severity or activity and depression each showed an independent association with the 4 SF-36 subscales62 of physical function, role limitation (physical), energy/vitality, and general health perception. This is in accordance with de Rooy et al,46 who found that people with IBD who were unable to work experienced poorer well-being and greater concerns about body image, interpersonal issues, and the general physical impact of illness.
Similarly, people in both the CCHS and NPHS samples who had specific comorbid chronic conditions (asthma, chronic bronchitis, back problems excluding arthritis, or migraine headaches) were more likely to be depressed. In addition, the CCHS sample studied fibromyalgia and chronic fatigue syndrome and found that people with these comorbid conditions were more likely to be depressed. Walker et al27 found that clients with psychiatric disorders were more likely to have both gastrointestinal and medically unexplained symptoms. Some of these conditions are likely to be coincidental rather than extraintestinal manifestations of IBD,63–65 but the similarity of findings in relation to depression in both samples is interesting. For the person who is ill, they represent an added burden of illness that can trigger depression.
The worrisome finding of high rates of recent and previous suicidal ideation among depressed respondents underlines the importance of mental health interventions. However, consistent with the pattern of undertreatment of major depression,66 only slightly more than half of all depressed people with IBD or a similar disorder reported that they had consulted a mental health professional. Even among those who did, many did not receive ongoing treatment. Fewer than half of the depressed patients had ≥4 visits in the preceding year. Furthermore, fewer than half of the depressed respondents were using antidepressants, and because antidepressant medication may be prescribed for other conditions, this may be an overestimate of treatment for depression. Thus, it appears that increased provision of treatment for depression and heightened monitoring of suicidal ideation would be helpful to this population.
In keeping with this finding of undertreatment of depression, depressed respondents were much more likely than nondepressed respondents to report unmet health needs. Although the question does not specify the nature of those unmet needs, it is likely that mental health issues play a prominent role.19
There are several limitations to this study. The designation of IBD was by self-report; study participants were not screened by a gastroenterologist. As discussed above, the wording of the question permitted those with similar bowel disorders to incorrectly classify themselves as having IBD. Longobardi and associates67 noted that this question results in few false negatives but does include substantial numbers of false positives who may not have IBD but have other bowel disorders such as irritable bowel syndrome. However, individuals with irritable bowel syndrome and IBD have been shown to experience comparable levels of depression68 and impairment in HRQOL.69 Therefore, the estimates of depression in people with IBD may not be biased substantially by this misclassification.
Depression was diagnosed by a reliable self-report tool, not by a psychologist or a psychiatrist. Although the CIDI-SF has been used in studies of adolescents,70,71 it appears not to have been validated specifically for pediatric and adolescent populations. Only 3% of our samples were individuals under the age of 20; therefore, it is unlikely that including adolescents seriously biases our finding.
Given these limitations, this study determined the prevalence and correlates of depression in people with IBD and similar bowel disorders from 2 nationally representative Canadian surveys. These individuals experienced rates of depression triple those of the general population. One in 6 depressed respondents reported suicidal ideation. Depression rates were higher among female respondents, younger respondents, those who reported greater pain, those without partners, and those who had functional limitations. Those who reported greater pain and were without social support were particularly vulnerable to depression. Only 40% of depressed individuals were using antidepressants. Between one third and one half of depressed respondents were not consulting any mental health professionals. It appears that many are not voluntarily presenting their mental health concerns to their clinicians. This study suggests that it is important for clinicians to proactively screen for depression and suicidal ideation among their patients with active IBD symptoms, particularly among those reporting moderate to severe pain.