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Keywords:

  • inflammatory bowel disease;
  • depression;
  • pain;
  • social support

Abstract

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. References

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.

MATERIALS AND METHODS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. References

Data Sources

This study investigated the relationship between demographic characteristics, a wide range of co-occurring chronic conditions, healthcare utilization patterns, and depression among Canadians with IBD. The decision was made to conduct the analyses in 2 independent data sets, particularly because many of these relationships have not, to the best of our knowledge, been previously explored in the literature. The Canadian Community Health Survey 1.1 (CCHS), conducted from 2000 through 2001, and the National Population Health Survey (NPHS), conducted from 1996 through 1997, are 2 large, nationally representative surveys using similar designs and questionnaires. The analyses reported in the present article used the public-use data files for these data sets from which all personal identifying information has been removed. Statistics Canada (the Canadian equivalent of the US Census Bureau) was responsible for data collection and the original ethics approval of and confidentiality of these data. Additional ethics approval is not required for any secondary data analysis of these public-use data sets.

Survey Design

National Population Health Survey

The NPHS is a longitudinal survey conducted by Statistics Canada that collects information about health and healthcare needs from a representative sample of the people living in Canada. This analysis examines the NPHS wave data gathered in Canada from June 1996 to August 1997. The survey collects information about health status, use of health services, and related demographic and economic information to understand the determinants of good health and to develop and evaluate health policies and programs. The target population of the NPHS is household residents throughout Canada, excluding people living on native reserves, on Canadian Forces bases, and in some remote areas. The sample for this survey is composed of 2 parts: (1) a longitudinal sample of respondents interviewed in 1994 through 1995 and reinterviewed in 1996 through 1997 in which households were sampled using a multistage stratified sampling design and 1 person was randomly selected from each household (n = 15,681), and (2) a cross-sectional sample of an additional 66,123 selected respondents in which respondents were sampled using Statistics Canada random-digit dialing system. The overall response rate for the combined sample of core and cross-sectional respondents was 82.6% for households and, within these, 95.6% for nonchild selected members. The total sample includes 81,804 selected respondents.31 Of these, 1520 reported that they had been “diagnosed by a health professional” with “a bowel disorder such as Crohn's disease or colitis,” “which had lasted or was expected to last 6 months or more.” When the 82 respondents (5.4%) with missing information for the depression measure were excluded, the final sample size was 1438.

Canadian Community Health Survey 1.1

The CCHS was gathered from 2000 through 2001 by Statistics Canada. The target population of the survey was the same as that of the NPHS, covering ≈98% of the Canadian population ≥12 years of age. The CCHS had a response rate of 84.7% after 14 months of collection, which resulted in a final sample of 130,880 respondents.31,32 Of the original 3157 respondents reporting that they had IBD or a similar disorder, 81 respondents (2.6%) had incomplete data on their depression index. Thus, the total sample for these analyses is 3076. The logistic regression analysis included only respondents with complete data on all 12 variables incorporated into the analysis (n = 2689).

Statistical Analysis Plan

The prevalence of depression among individuals with IBD or a similar disorder was calculated in both data sets. Within each subsample of individuals with IBD, bivariate analyses were conducted to compare the depressed (n = 501 CCHS and n = 211 NPHS) and nondepressed (n = 2575 CCHS and n = 1227 NPHS). We conducted χ2 analyses for categorical variables and independent t tests for interval and ratio level variables. A logistic regression analysis also was conducted in the CCHS data set. Additional bivariate analyses were conducted among the 501 depressed respondents with IBD in the CCHS to assess risk factors for suicidal ideation. All of the data were weighted to adjust for probability of selection so that the respondents were demographically representative of the Canadian population. Unless otherwise noted, the questions and measures in the CCHS and NPHS are identical.

Identification of IBD Patients

The question about IBD was nested in a long list of chronic illnesses. The preamble to that list began with, “Now I'd like to ask about certain chronic health conditions which you may have. We are interested in 'long-term conditions' that have lasted or are expected to last 6 months or more and that have been diagnosed by a health professional.” After being asked about several other chronic diseases such as asthma and diabetes, the respondents were asked, “Do you have a bowel disorder such as Crohn's disease or colitis?” We have classified all of those responding affirmatively as if they had IBD, although this grouping may include other individuals with similar bowel disorders. Respondents were diagnosed as depressed if they had a probability of depression of ≥90% as classified by the Kessler and Mroczek scale based on a subset of items from the Composite International Diagnostic Interview (CIDI).33,34 The questions cover a cluster of symptoms for depressive disorder, which are listed in the 1987 Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association.35 This short-form (SF) scale was developed to operationalize criteria A through C of the DSM-III-R diagnosis of major depressive episode. The sensitivity and specificity of the CIDI-SF were 89.6% and 93.9%, respectively, with a total classification accuracy of 93.2% for a major depressive episode compared with the CIDI.34 A cutpoint of 90% had been used in other research studies.36–39

Independent Variables

The following demographic variables were investigated: gender; marital status (married or living common-law vs widowed/separated/divorced, single, or never married); age (measured by decade: 12-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, and ≥80 years of age, with the midpoints of these age groups used to establish mean age); education level (less than secondary school graduation vs secondary school graduation and higher); race (self-report: white vs visible minority); immigrant status (Canadian-born vs immigrant); and total household income.

The measure of food insecurity differed between the 2 data sets. In the CCHS, food insecurity was assessed through the following question: “In the past 12 months, how often did you or anyone else in your household not have enough food to eat because of a lack of money?” (The choices were never vs sometimes or often.) In the NPHS, food insecurity was measured through the question, “Thinking about the past 12 months, did your household ever run out of money to buy food?”

Health Indicators

Self-reported health status was derived from the question, “In general, would you say your health is excellent, very good, good, fair, or poor?” The responses were dichotomized into excellent, very good, or good versus fair or poor.

The respondents were defined as having limitations in their instrumental activities of daily living (IADL) if they reported that they needed the help of another person in one of the following activities because of any condition or health problem: preparing meals, shopping for groceries or other necessities, or doing normal housework.

The respondents were defined as having limitations in their activities of daily living (ADL) if they reported that they needed the help of another person in either personal care such as washing, dressing, or eating and/or in moving about inside the house.

The CCHS participants were asked if they were usually free of pain and discomfort. If they responded no, they were asked how many activities their pain or discomfort prevented (none, a few, some, most). The answers were then dichotomized into 2 categories (usually no pain or discomfort or pain prevents no activities vs pain prevents few activities, some activities, or most activities). The NPHS respondents were asked to describe the “usual intensity of [their] pain or discomfort” (none, mild, moderate, severe).

By definition, all of the respondents in this study had at least 1 chronic condition: IBD or a similar bowel disorder. The number of additional chronic conditions among the CCHS respondents was calculated by summing the number of the following 16 conditions that the respondent reported having lasted ≥6 months that had been diagnosed by a health professional: asthma, fibromyalgia, arthritis or rheumatism, back problems, migraine headaches, cataracts, chronic bronchitis, emphysema or chronic obstructive pulmonary disease, diabetes, epilepsy, heart disease, cancer, stomach or intestinal ulcers, effects of a stroke, glaucoma, and chronic fatigue syndrome. In the NPHS data set, the list of potential chronic conditions did not include chronic fatigue syndrome or fibromyalgia.

Respondents' contact with mental health professionals was determined by the question, “In the past 12 months, have you seen or talked on the telephone to a health professional: a) family doctor, b) psychiatrist, and c) psychologist about your emotional or mental health?” Those who answered yes were asked how many times they visited a mental health professional (coded as no visits, 1–3 visits, ≥4 visits). Use of self-help groups was determined through the question, “Did the respondent attend a self-help group such as Alcoholics Anonymous or a cancer support group in the past 12 months?”

Self-perceived unmet healthcare needs were determined by respondents' answers to the following question: “During the past 12 months, was there ever a time when you felt that you needed health care but you didn't receive it?”

Respondents in the CCHS were asked 2 questions on suicidal ideation: “Have you ever seriously considered committing suicide or taking your own life?” Those who said yes were asked, “Has this happened in the past 12 months?” Thus, our constructed suicidal ideation has 3 response levels: considered suicide in the past 12 months, considered suicide previously, or never considered suicide. In the bivariate analyses of suicidal ideation, the first 2 response categories, listed above, were collapsed into 1 category. Only certain health regions opted to include these questions; thus, the sample size for this question is considerably smaller (n = 1437 respondents with IBD)

Drug Use Questions

In the CCHS, only certain regions opted to include the supplemental questions on drug use. Respondents from these regions were asked, “In the past month, that is, from one month ago until yesterday, did you take a) tranquilizers such as Valium, b) anti-depressants such as Prozac, Paxil or Effexor, or c) sleeping pills?” In the NPHS, all respondents were asked the above question, except that item b stated only “anti-depressants” and did not mention Prozac, Paxil, or Effexor.

RESULTS

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. References

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
  1. * In the CCHS, of the original 3157 respondents reporting that they had IBD or a similar bowel disorder, 81 respondents (2.6%) had incomplete data on their depression index. Thus, the total sample for these analyses is 3076.

  2. † In the NPHS, 82 of the 1520 respondents (5.4%) with IBD or a similar bowel disorder had missing data on depression. Therefore, the total NPHS sample for these analyses is 1438.

  3. ‡ Mean using midpoint of categories.

Demographic characteristics
Female65.878.267.8G0.00168.185.870.7G0.001
Common-law/married64.151.662.1G0.00153.856.954.20.40
Age, yr
12Y192.81.62.6G0.0013.22.93.1G0.001
20Y2912.016.412.7 13.816.714.2 
30Y3914.322.615.6 18.631.620.5 
40Y4920.529.321.9 20.325.821.1 
50Y5918.918.818.9 12.013.412.2 
60Y6912.36.411.3 12.75.711.7 
70Y7912.83.811.3 11.63.310.4 
Q80+6.51.25.6 7.80.56.7 
Mean age,1 yr50.543.2 G0.00149.541.1 G0.001
 (SD = 17.9)(SD = 13.9)  (SD = 19.3)(SD = 14.1)  
 (n = 2575)n = 501  (n = 1227)(n = 210)  
Education level
Not a high school27.019.825.90.00128.721.427.60.03
graduate
White93.392.393.10.4596.696.796.60.94
Immigrants17.812.416.90.00313.37.112.40.01
Mean income,148,66244,605 G0.0135,98136,811 0.65
Canadian $(SD = 27,588)(SD = 27,375)  (SD = 23,647)(SD = 22,169)  
 (n = 2306)(n = 462)  (n = 1029)(n = 189)  
Food insecurity17.837.821.1G0.001    
Household ran out NA  12.022.413.5G0.001
of money to buy food
Has someone NA  90.787.190.20.11
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
  1. * In the CCHS, of the original 3157 respondents reporting that they had IBD or a similar bowel disorder, 81 respondents (2.6%) had incomplete data on their depression index. Thus, the total sample for these analyses is 3076.

  2. † In the NPHS, 82 of the 1520 respondents (5.4%) with IBD or a similar bowel disorder had missing data on depression. Therefore, the total NPHS sample for these analyses is 1438.

Health-related characteristics
Self-reported health status
Fair/poor32.352.235.6G0.00130.547.633.0G0.001
Excellent/very67.747.864.4 69.552.467.0 
good/good
ADL limitations8.812.29.30.0 NA 0.02
IADL limitations20.633.822.8G0.001    
Activities prevented35.158.438.9G0.001 NA  
by pain
Activity limitations NA  48.472.051.8G0.001
(whether or not
caused by pain)
Level of pain
No pain NA  61.248.659.3G0.001
Mild pain    9.210.09.3 
Moderate pain    21.321.021.2 
Severe pain    8.320.510.1 
Number of chronic conditions
Has IBD and no other24.6 (n = 725)20.223.9G0.00114.29.613.50.03
chronic conditions
Has IBD and 128.0 (n = 798)17.826.3 21.216.320.5 
additional chronic
condition
Has IBD and Q247.4 (n = 1510)62.049.8 64.674.066.0 
additional chronic
conditions
Prevalence of other chronicconditions
Cancer4.75.04.80.804.67.24.90.11
Diabetes6.48.26.70.156.45.76.60.60
Asthma12.718.313.60.0019.522.911.5G0.001
Arthritis or rheumatism38.642.339.20.1238.135.237.70.43
Back problems34.644.836.2G0.00125.943.328.5G0.001
excluding arthritis
Migraine headaches19.038.122.1G0.00115.627.517.3G0.001
Fibromyalgia5.014.76.6G0.001
Epilepsy1.11.81.20.18
Heart disease11.27.010.50.00512.68.111.90.06
Suffers from the2.31.42.10.213.81.03.40.03
effects of stroke
Stomach/intestinal ulcers
Glaucoma3.72.23.50.093.51.03.10.05
Cataract11.03.89.8G0.0019.62.98.6G0.001
Chronic fatigue syndrome2.311.63.8G0.001

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).

thumbnail image

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).

Download figure to PowerPoint

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
  1. *In the CCHS, of the original 3157 respondents reporting that they had IBD or a similar bowel disorder, 81 (2.6%) respondents had incomplete data on their depression index. Thus the total sample for these analyses is 3076.

  2. †In the NPHS, 82 (5.4%) of the 1520 respondents with IBD or a similar bowel disorder had missing data on depression. Therefore, the total NPHS sample for these analyses is 1438.

  3. ‡In the CCHS, only 1103 individuals with IBD were asked this question.

Healthcare utilization characteristics       
Consulted mental health professional11.152.417.9<0.001    
Mental health visits, n        
088.947.682.2G0.00190.037.382.3<0.001
1–35.821.48.4 4.513.45.8 
4–125.331.09.5 5.649.311.9 
Consulted mental health professionalYfamily doctor6.026.99.4G0.001    
Consulted mental health professional-psychiatrist2.312.84.0<0.001    
Consulted mental health professional-psychologist1.712.43.5<0.001    
Consulted social worker for mental health use2.112.43.8<0.001    
Attended self-help group4.713.26.1<0.0015.613.86.8<0.001
Felt that health care was needed but did not receive it22.441.125.4<0.00111.321.412.7<0.001
Drug use        
Used antidepressants in the past month‡7.2 (n = 67)26.2 (n = 44)10.1<0.0019.240.213.7<0.001
Used tranquilizers in the past month NA  6.329.29.6<0.001
Used sleeping pills in the past month NA  7.621.99.7<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 ConfidenceOdds Ratio (95% Interval)P
Demographic characteristics  
Female1.67 (1.28Y2.18)<0.001
Age by decade, yr  
12-193.27 (1.02Y10.51)0.047
20–299.14 (3.74–22.33)<0.001
30–3911.79 (4.87–28.53)<0.001
40–499.70 (4.09–23.01)<0.001
50–595.70 (2.39–13.58)<0.001
60–693.22 (1.29–8.08)0.012
70–791.33 (0.50–3.55)<0.001
Q80 (Reference)  
Immigrant status  
Reference: Canadian-born0.72 (0.50–1.04)0.08
Marital status  
Unmarried (never married,1.78 (1.39–2.28)<0.001
separated, divorced)  
Reference:married/common-law 
Education  
Secondary school1.35 (1.01–1.81)0.045
graduation and higher  
Reference: less than secondaryschool graduation 
Race  
White0.89 (0.56–1.43)0.63
Reference: visible minority  
Derived income adequacycategory 
Middle income1.42 (0.99–2.04)0.056
High income1.27 (0.89–1.83)0.21
Reference, low income  
Food insecurity  
Reference: no1.55 (1.19–2.01)0.001
Health-related characteristics  
Self-reported health status  
Fair/poor health1.93 (1.48–2.50)<0.001
Reference: excellent/verygood/good health 
Chronic conditions  
Has IBD and 1 additional0.83 (0.59–1.17)0.291
chronic condition  
Has IBD and Q2 additional1.31 (0.95–1.80)0.099
chronic conditions  
Reference: has IBD and noother chronicconditions
Activity limitations  
ADL limitations0.71 (0.47–1.09)0.119
IADL limitations1.49 (1.10–2.03)0.011
Reference: no ADL/IADLlimitations 
Activities prevented by pain  
Reference: no1.71 (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.

DISCUSSION

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. References

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.

References

  1. Top of page
  2. Abstract
  3. MATERIALS AND METHODS
  4. RESULTS
  5. DISCUSSION
  6. References
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