Major depression and secondhand smoke exposure

BACKGROUND

Epidemiological studies have consistently linked smoking to poor mental health. Among non-smokers, some studies have also reported associations between secondhand smoke exposure and psychological symptoms. However, an association between secondhand smoke exposure and depressive disorders has not been well established.

METHODS

This analysis used cross-sectional data from a series of 10 population surveys conducted in Canada between 2003 and 2013. The surveys targeted the Canadian household population, included a brief structured interview for past year major depressive episode (MDE) and included items assessing secondhand smoke exposure. We used two-stage individual-level random-effects meta-regression to synthesize results from these surveys.

RESULTS

Over the study interval, about 20% of non-smokers reported substantial exposure to secondhand smoke. In this group, the pooled annual prevalence of MDE was 6.1% (95% CI 5.3-6.9) compared to 4.0% (95% CI 3.7-4.3) in non-smokers without secondhand smoke exposure. The crude odds ratio was 1.5 (95% CI 1.4-1.7). With adjustment for a set of potential confounding variables the odds ratio was unchanged, 1.4 (95% CI 1.2 - 1.6).

CONCLUSIONS

These results provide additional support for public health measures aimed at reducing secondhand smoke exposure. A causal connection between secondhand smoke exposure and MDEs cannot be confirmed due to the cross-sectional nature of the data. Longitudinal studies are needed to establish temporal sequencing.

The depression and marital status relationship is modified by both age and gender

BACKGROUND

Marital status is associated with major depression prevalence, however, the strength of association may be modified by age and gender.

METHODS

The data sources were a series of cross sectional national health surveys of the Canadian population carried out by Statistics Canada during 1996-2013. These were cross-sectional files from the National Population Health Survey of 1996, together with the Canadian Community Health Surveys from 2000 to 2013; the respondents were 18 years and older. The data was analyzed with meta-analytic techniques and logistic regression.

RESULTS

In terms of gender, the odds ratios of depression were smaller for females (vs males) who were single, widowed or separated compared to married people. Regarding age, the odds ratios for depression showed a steady rise with increasing age for those in single and in common-law relationships compared to married people. In contrast the odds ratios for depression declined with age for those widowed, separated and divorced compared to married people. The strength of the interaction terms used to quantify these moderating effects showed no change from 1996 to 2013.

LIMITATIONS

Only one member of each household was included, so that relationship issues could not be studied. The generalizability of our findings requires international data. Also the diagnostic interviews used are not as accurate as clinical assessments.

CONCLUSION

Use of large numbers of participants has revealed some robust modifying effects of both gender and age on the depression/marital status relationship. The clinical significance of our findings is that the vulnerability to development of depression is not only related to marital status, but that this relationship is modified by age and gender.

Major depression and non-specific distress following smoking cessation in the Canadian general population

BACKGROUND

Outcome data from smoking cessation trials indicate that improvement in mental health occurs after smoking cessation. This suggests that smoking cessation should be a priority for mental health services. However, participants in such trials may not be representative of the general population. This study investigates changes in mental health following smoking cessation in a set of general population samples.

METHODS

Data from a library of cross-sectional surveys conducted by Statistics Canada between 2001 and 2013 were included in this analysis. Survey estimates were pooled in order to increase precision. Associations between smoking (and smoking cessation), major depressive episodes (MDE) and non-specific distress (assessed using the K-6 scale) were evaluated using meta-analysis and meta-regression techniques.

RESULTS

The annual prevalence of major depression was higher in daily (11.0%) than in never smokers (4.4%). The prevalence in former daily smokers was 5.1%. The prevalence of MDE and distress was elevated in those recently quitting but returned to baseline levels within one year.

CONCLUSIONS

After smoking cessation, indicators of mental health improve over time, especially in the first year. The findings support the idea that smoking cessation should be a part of the management of common mood and anxiety disorders. However, due to its observational nature this study in itself cannot confirm causality, sustained abstinence may be an effect of improved mental health rather than its cause.

LIMITATIONS

The cross-sectional nature of the constituent surveys does not allow causal inference. No biological measures (e.g. cotinine) were available.

A comparison of recommendations and received treatment for mood and anxiety disorders in a representative national sample

BACKGROUND

The exact nature of treatment and management recommendations made, and received, for mood and anxiety disorders in a community population is unclear. In addition, there is limited evidence on the impact of recommendations on actual receipt of treatment or implementation of management strategies. We aim to describe the frequency with which specific recommendations were made and implemented; and thus assess the size of any gap between the recommendation and implementation of treatments and management strategies.

METHODS

We used the Survey 'Living with a Chronic Condition in Canada - Mood and Anxiety Disorders (SLCDC-MA), a unique crossectional survey of a large (N = 3358) and representative sample of Canadians with a diagnosed mood or anxiety disorder, which was conducted by Statistics Canada. The survey collected information on recommendations for medication, counselling, exercise, reduction of alcohol consumption, smoking cessation and reduction of street drug use. We also estimate the frequency that recommendations are made and followed, as well the impact of the prior on the latter. We consulted people with lived experience of the disorders to help interpret our results.

RESULTS

The results generally showed that most people would receive recommendations, almost all for antidepressant medications (94.6%), with lower proportions for the other treatment and management strategies (e.g. 62.1 and 66% for counselling and exercise). Most recommendations were implemented and had an impact on behaviour. The exception to this was smoking reduction/cessation, which was often not recommended or followed through. Other than with medication, at least 20% of the population, for each recommendation, would not have their recommendation implemented. A substantive group also exists who access treatments, and employ various management strategies, without a recommendation.

CONCLUSIONS

The results indicate that there is a gap between recommendations made and the implementation of treatments. However, its size varies substantially across treatments.

Is the prevalence of major depression increasing in the Canadian adolescent population? Assessing trends from 2000 to 2014

BACKGROUND

Major depressive disorder is a relatively common diagnosis with onset across the lifespan. There is a recent belief that major depressive episodes (MDE) are increasing in adolescence; however, it is not clear if this is truly an increase in prevalence or reflective of other causes such as change in diagnostic patterns. This study aimed to determine whether evidence supports an epidemic of MDE in Canadian adolescents.

METHODS

Past year MDE prevalence estimates were derived from a series of nationally representative surveys. Random effects meta-regression and graphical analyses were used to evaluate trends. A post hoc analysis compared trends in MDE prevalence to trends in self-reported mood disorder diagnosis (made by a health professional). The sample was split into 9 birth cohorts to examine whether MDE prevalence increased in more recent cohorts.

RESULTS

Prevalence of MDE did not significantly change between 2000 and 2014 (β=0.001; p=0.532), and there was no modification of trends by sex or age. However, prevalence of self-reported mood disorder diagnosis by a health professional increased from 2003 to 2014 (β=0.001; p=0.024). There was no indication that MDE prevalence differed by birth cohort.

LIMITATIONS

Limitations include reduced precision in subgroup analyses, lack of clinical judgement in the structured diagnostic interview, and inability to differentiate mild, moderate and severe episodes of depression.

CONCLUSION

These findings do not support an epidemic of MDE in adolescents, however as more individuals report diagnoses by a health professional, future policy may need to incorporate an increase in need of mental health services.

The Prevalence of Major Depressive Episodes Is Higher in Urban Regions of Canada

OBJECTIVE

Major depressive disorder is an important contributor to disease burden. Anticipation of service needs is important, yet basic information is lacking. For example, there is no consensus as to whether major depressive episodes (MDE) are more or less prevalent in urban or rural areas. The objective of this study was to determine whether a difference exists in Canada.

METHOD

A series of 11 Canadian national cross-sectional studies were examined from 2000 to 2014, providing much greater precision than prior analyses. Survey-specific MDE prevalence estimates were synthesized into a pooled odds ratio comparing urban to rural areas using meta-analytic methods.

RESULTS

Differences in the survey-specific estimates were not in excess of what would be expected due to sampling variability. This suggests that inconsistency in the prior literature is due to inadequate power and precision, an issue addressed by the meta-analytic pooling. The pooled odds ratio for Canada is 1.18 (95% confidence interval, 1.12 to 1.25), indicating that urban regions have higher MDE prevalence than rural regions. However, the difference is very small and of uncertain significance for policy and planning.

CONCLUSIONS

Prevalence of MDE is approximately 18% higher in urban compared to rural regions of Canada. The difference is insufficient to impute differing need for services, but the result resolves an inconsistency in the existing literature and may play a role in future needs assessment.

Major Depression Prevalence Increases with Latitude in Canada

OBJECTIVE

To determine whether there is an association between latitude and annual major depressive episode (MDE) prevalence in Canada.

METHODS

Data from 2 national survey programs (the National Population Health Survey and the Canadian Community Health Survey) were used, providing 10 data sets collected between 1996 and 2013, together including 922,260 respondents, of whom 495,739 were assessed for MDE using 1 of 2 versions of the Composite International Diagnostic Interview, a short-form version (8 studies), and a Canadian adaptation of the World Mental Health version (2 studies). Approximate latitude was determined by linkage to postal code data. Data were analyzed using logistic regression and pooled across surveys using individual-level meta-analytic methods.

RESULTS

In models including latitude as a continuous variable, a statistically significant association was observed, with prevalence increasing with increasing latitude. This association persisted after adjustment for a set of known risk factors. The latitude gradient was modest in magnitude, a 1% to 2% increase in the prevalence odds of MDE per degree of latitude was observed. Due to sparse data, this gradient cannot be confidently generalized beyond major population centres, which tend to occur at less than 55° latitude in Canada.

CONCLUSION

A latitude gradient has not previously been reported. If replicated, the gradient may have implications for the planning of services and generation of aetiological hypotheses. However, this cross-sectional analysis cannot confirm aetiology and could not evaluate the potential contributions of variables such as light exposure, weather patterns, or social determinants.

Descriptive Epidemiology of Generalized Anxiety Disorder in Canada

OBJECTIVE

The first national survey to assess the prevalence of generalized anxiety disorder (GAD) in Canada was the 2012 Canadian Community Health Survey: Mental Health and Well-Being (CCHS-MH). The World Mental Health Composite International Diagnostic Interview (WMH-CIDI), used within the representative sample of the CCHS-MH, provides the best available description of the epidemiology of this condition in Canada. This study uses the CCHS-MH data to describe the epidemiology of GAD.

METHOD

The analysis estimated proportions and odds ratios and used logistic regression modelling. All results entailed appropriate sampling weights and bootstrap variance estimation procedures.

RESULTS

The lifetime prevalence of GAD is 8.7% (95% CI, 8.2% to 9.3%), and the 12-month prevalence is 2.6% (95% CI, 2.3% to 2.8%). GAD is significantly associated with being female (OR 1.6; 95% CI, 1.3 to 2.1); being middle-aged (age 35-54 years) (OR 1.6; 95% CI, 1.0 to 2.7); being single, widowed, or divorced (OR 1.9; 95% CI, 1.4 to 2.6); being unemployed (OR 1.9; 95% CI, 1.5 to 2.5); having a low household income (<$30 000) (OR 3.2; 95% CI, 2.3 to 4.5); and being born in Canada (OR 2.0; 95% CI, 1.4 to 2.8).

CONCLUSIONS

The prevalence of GAD was slightly higher than international estimates, with similar associated demographic variables. As expected, GAD was highly comorbid with other psychiatric conditions but also with indicators of pain, stress, stigma, and health care utilization. Independent of comorbid conditions, GAD showed a significant degree of impact on both the individual and society. Our results show that GAD is a common mental disorder within Canada, and it deserves significant attention in health care planning and programs.

Trends in binge drinking in Canada from 1996 to 2013: a repeated cross-sectional analysis

BACKGROUND

Heavy drinking is a major factor in morbidity and mortality worldwide. Little information is available on trends in Canada regarding alcohol abuse. We sought to estimate abstinence, binge drinking and alcohol intake exceeding low-risk drinking guidelines in the Canadian population from 1996 to 2013.

METHODS

The data sources for this analysis were a series of cross-sectional national health surveys of the Canadian population carried out by Statistics Canada between 1996 and 2013. These were cross-sectional files from the National Population Health Surveys of 1996 and 1998, plus the Canadian Community Health Surveys from 2000 to 2013. Respondents were aged 18 years and older.

RESULTS

The proportion of binge drinkers increased steadily from 13.7% (95% confidence interval [CI] 13.2%-14.2%) in 1996 to 19.7% (95% CI 19.1%-20.3%) in 2013. The corresponding proportions for men were 20.8% (95% CI 19.9%-21.7%) in 1996, and 25.7% (95% CI 24.7%-26.6%) in 2013; for women, these proportions were 6.9% (95% CI 6.4%-7.5%) in 1996, and 13.8% (95% CI 13.1%-14.5%) in 2013. No significant increases were seen in the proportion of people who exceeded low-risk drinking guidelines or of abstainers during the same period.

INTERPRETATION

The rate of self-reported binge drinking in Canada has increased from 1996 to 2013, relatively more so among women than among men. No evidence of an increase in the proportion of people exceeding low-risk drinking guidelines or of abstainers was seen during the same period. These results suggest that binge drinking is of particular concern regarding intervention strategies aimed at improvement of public health.

Perceived Stigma among Recipients of Mental Health Care in the General Canadian Population

OBJECTIVES

The Mental Health Experiences Scale is a measure of perceived stigma, the perception of negative attitudes and behaviours by people with mental disorders. A recent Canadian survey (Canadian Community Health Survey-Mental Health) included this scale, providing an opportunity to describe perceived stigma in relation to diagnosis for the first time in the Canadian general population.

METHODS

The survey interview began with an assessment of whether respondents had utilised services for an "emotional or mental health problem" in the preceding 12 months. The subset reporting service utilisation were asked whether others "held negative opinions" about them or "treated them unfairly" for reasons related to their mental health. The analysis reported here used frequencies, means, cross-tabulation, and logistic regression, all incorporating recommended replicate sampling weights and bootstrap variance estimation procedures.

RESULTS

Stigma was perceived by 24.4% of respondents accessing mental health services. The frequency was higher among younger respondents (<55 years), those who were not working, those reporting only fair or poor mental health, and the subset who reported having received a diagnosis of a mental disorder. Sex and education level were not associated with perceived stigma. People with schizophrenia reported stigmatization only slightly more frequently than those with mood and anxiety disorders.

CONCLUSIONS

Stigmatization is a common, but not universal, experience among Canadians using services for mental health reasons. Stigmatization was a problem for a sizeable minority of respondents with mood, anxiety, and substance use disorders as well as bipolar and psychotic disorders.

The association between major depression prevalence and sex becomes weaker with age

BACKGROUND

Women have a higher prevalence of major depressive episodes (MDE) than men, and the annual prevalence of MDE declines with age. Age by sex interactions may occur (a weakening of the sex effect with age), but are easily overlooked since individual studies lack statistical power to detect interactions. The objective of this study was to evaluate age by sex interactions in MDE prevalence.

METHODS

In Canada, a series of 10 national surveys conducted between 1996 and 2013 assessed MDE prevalence in respondents over the age of 14. Treating age as a continuous variable, binomial and linear regression was used to model age by sex interactions in each survey. To increase power, the survey-specific interaction coefficients were then pooled using meta-analytic methods.

RESULTS

The estimated interaction terms were homogeneous. In the binomial regression model I (2) was 31.2 % and was not statistically significant (Q statistic = 13.1, df = 9, p = 0.159). The pooled estimate (-0.004) was significant (z = 3.13, p = 0.002), indicating that the effect of sex became weaker with increasing age. This resulted in near disappearance of the sex difference in the 75+ age group. This finding was also supported by an examination of age- and sex-specific estimates pooled across the surveys.

CONCLUSIONS

The association of MDE prevalence with sex becomes weaker with age. The interaction may reflect biological effect modification. Investigators should test for, and consider inclusion of age by sex interactions in epidemiological analyses of MDE prevalence.

Major Depression in Canada: What Has Changed over the Past 10 Years?

OBJECTIVE

Major depressive episodes (MDE) make an important contribution to disease burden in Canada. The epidemiology of MDE in the national population has been examined in 2 mental health surveys, one conducted in 2002 and the other in 2012. Our objective was to compare selected variables from the 2 surveys to determine whether changes have occurred in the prevalence, treatment, and impact of MDE.

METHOD

The World Health Organization World Mental Health Composite International Diagnostic Interview was used in both surveys and the MDE module (which was not modified) was scored using the same algorithm. Some variables assessing impact and management of MDE were also identical in the 2 surveys. The analysis was based on frequency estimates and associated 95% confidence intervals.

RESULTS

The annual prevalence of MDE was 4.7% (95% CI 4.3% to 5.1%) in 2012, nearly identical to 4.8% (95% CI 4.5% to 5.1%) in 2002. Receipt of potentially adequate treatment (defined as taking an antidepressant or 6 or more visits to a health professional for mental health reasons) increased from 41.3% in 2002 to 52.2% in 2012, mostly due to an increase in respondents reporting 6 or more visits. Use of second generation antipsychotics also increased. There was no evidence of diminishing prevalence or impact (as assessed by symptoms of distress).

CONCLUSIONS

There appears to have been an increase in receipt of treatment for people with MDE and a changing pattern of management. However, it was not possible to confirm that the impact of MDE is diminishing as a result.

Why is major depression prevalence not changing?

BACKGROUND

Increasing provision of treatment should theoretically lead to a decreased burden of major depressive episodes (MDE) in the population. However, there is no evidence yet that this has occurred. Among possible explanations are that: (1) treatment may not be sufficiently accessible, effective or effectively delivered to make a difference at the population level or (2) treatment benefits such as diminished episode duration may be offset by other trends such as increasing episode incidence, or vice versa.

METHODS

MDE prevalence has been assessed in a series of national surveys and in a single national longitudinal study in Canada. These studies included a short form version of the Composite International Diagnostic Interview module for major depression. Indicators of incidence and episode duration of MDE were estimated. Meta-regression methods were used to examine trends over time.

RESULTS

No evidence of increasing incidence nor of diminishing duration of MDE was found. The analysis failed to uncover evidence that the epidemiology of this condition has been changing.

LIMITATIONS

Most studies included in this analysis used an abbreviated interview for MDE which may lack sensitivity and/or specificity. These studies could not address potential benefits of treatment on prevention of suicide. Some potentially offsetting effects could not be assessed, e.g. economic or societal changes.

CONCLUSION

These results suggest that more effective efforts to prevent MDE, or to improve the volume or quality of treatment, are necessary to reduced burden of MDE in the population.

Depression--a common disorder across a broad spectrum of neurological conditions: a cross-sectional nationally representative survey

OBJECTIVE

To estimate the prevalence of depression across a range of neurological conditions in a nationally representative sample.

METHODS

The data source was the Survey of Living with Neurological Conditions in Canada (SLNCC), which accrued its sample by selecting participants from the Canadian Community Health Survey. The point prevalence of depression was estimated by assessment of depressive symptoms with the Patient Health Questionnaire, Brief (Patient Health Questionnaire, 9-item).

RESULTS

A total of n=4408 participated in the SLNCC. The highest point prevalence of depression (>30%) was seen in those with traumatic brain injury and brain/spinal cord tumors. Depression was also highly prevalent (18-28%) in those with (listed from highest to lowest) Alzheimer's disease/dementia, dystonia, multiple sclerosis, Parkinson's disease, stroke, migraine, epilepsy and spina bifida. The odds ratios for depression, with the referent group being the general population, were significant (from highest to lowest) for migraine, traumatic brain injury, stroke, dystonia and epilepsy.

CONCLUSIONS

All neurological conditions included in this study are associated with an elevated prevalence of depression in community populations. The conditions with the highest prevalence are traumatic brain injury and brain/spinal cord tumors.

Prevalence of Bipolar I and II Disorder in Canada

OBJECTIVE

Current epidemiologic knowledge about bipolar disorder (BD) in Canada is inadequate. To date, only 3 prevalence studies have been conducted: only 1 was based on a national sample, and none distinguished between BD I and II. The objective of this study was to estimate the prevalence of BD I and II in Canada in 2012.

METHOD

Data were obtained from the 2012 Canadian Community Health Survey: Mental Health and Well-being, a cross-sectional survey of a nationally representative sample of household residents ages 15 years and older (n = 25 113). The survey response rate was 68.9%. Interviews were based on the World Health Organization Composite International Diagnostic Interview (CIDI). Prevalence was estimated using generalized linear modelling. Prevalence of self-reported diagnosis of BD and use of lithium were also estimated.

RESULTS

The estimated lifetime prevalence of BD I and II (based on the CIDI) in Canada in 2012 was 0.87% (95% CI 0.67% to 1.07%) and 0.57% (95% CI 0.44% to 0.71%), respectively. Prevalence did not differ by sex. The estimated prevalence of self-reported BD was 0.87% (95% CI 0.65% to 1.07%). There was a lack of congruence between CIDI-defined and self-reported BD, and few people taking lithium were positive for BD on the CIDI, which raises some concerns about the validity of the CIDI's assessment of BD.

CONCLUSIONS

These prevalence estimates align with those reported in prior literature. However, caution should be exercised when interpreting general population studies that use CIDI-defined BD owing to the possibility of misclassification.

The prevalence of major depression is not changing

OBJECTIVE

To evaluate trends in the prevalence of major depressive episodes (MDEs) in Canada during the past 2 decades using data collected in a series of national surveys.

METHOD

MDE prevalence has been assessed in national surveys that either used a short form version of the Composite International Diagnostic Interview Short Form for Major Depression (CIDI-SFMD) or an adaptation of the World Health Organization's (full-length) version, World Mental Health (WMH) CIDI. We applied meta-regression methods to adjust for instrument type while also addressing design effects in the individual data sets. Interprovincial differences that might have confounded estimation of national trends were also explored.

RESULTS

Interprovincial differences were not found to be significant, nor were time by province interactions. Estimates based on the WMH-CIDI were about 1% lower than those using the CIDI-SFMD. There was no evidence of changing prevalence over time, with slope for time, adjusted for assessment instrument, being nearly zero (β=0.0007, P=0.24).

CONCLUSION

An extensive collection of surveys conducted in Canada between 1994 and 2012 provide an opportunity to examine long-term trends in the prevalence of major depression. MDE prevalence has not changed during this period of time.

Descriptive epidemiology of major depressive disorder in Canada in 2012

OBJECTIVE

The epidemiology of major depressive disorder (MDD) was first described in the Canadian national population in 2002. Updated information is now available from a 2012 survey: the Canadian Community Health Study-Mental Health (CCHS-MH).

METHOD

The CCHS-MH employed an adaptation of the World Health Organization World Mental Health Composite International Diagnostic Interview and had a sample of n=25 113. Demographic variables, treatment, comorbidities, suicidal ideation, and perceived stigma were assessed. The analysis estimated adjusted and unadjusted frequencies and prevalence ratios. All estimates incorporated analysis methods to account for complex survey design effects.

RESULTS

The past-year prevalence of MDD was 3.9% (95% CI 3.5% to 4.2%). Prevalence was higher in women and in younger age groups. Among respondents with past-year MDD, 63.1% had sought treatment and 33.1% were taking an antidepressant (AD); 4.8% had past-year alcohol abuse and 4.5% had alcohol dependence. Among respondents with past-year MDD, the prevalence of cannabis abuse was 2.5% and that of dependence was 2.9%. For drugs other than cannabis, the prevalence of abuse was 2.3% and dependence was 2.9%. Generalized anxiety disorder was present in 24.9%. Suicide attempts were reported by 6.6% of respondents with past-year MDD. Among respondents accessing treatment, 37.5% perceived that others held negative opinions about them or treated them unfairly because of their disorder.

CONCLUSIONS

MDD is a common, burdensome, and stigmatized condition in Canada. Seeking help from professionals was reported at a higher frequency than in prior Canadian studies, but there has been no increase in AD use among Canadians with MDD.

Depression as a predictor of occupational transition in a multiple sclerosis cohort

In MS, transitions between working and not-working status may occur in association with depression. This can complicate patients' ability to promptly obtain disability support due to an expectation that their functioning will improve after the depression resolves, a viewpoint that sees depression assuming a role as a causal determinant of disability. In this study, prospective data were used to model the relationship between depressive symptoms and the transition out of employment. In unadjusted analyses, depression increased the risk of transition to non-working status, HR = 1.7 (95%CI 1.3-2.3). Adjustments for ambulation status, physical and mental quality of life composite scores and fatigue impact attenuated or eliminated the association. While depression commonly occurs around the time of occupational transitions in MS, it does not appear to be an independent or direct cause of such transitions.

Antidepressant use in Canada has stopped increasing

OBJECTIVE

Large increases in the use of antidepressants (ADs) were reported in the past 2 decades in many countries, including Canada. Our objective was to determine whether this pattern of increasing use has continued, using data from a 2012 national mental health survey.

METHOD

During the past 2 decades, a series of Canadian national health surveys have evaluated AD use in the household population. Some of these surveys have assessed past 2-day use whereas others have assessed self-reported past-month use. We applied meta-regression methods as a methodological strategy to address this heterogeneity and to examine long-term trends, incorporating 2012 data.

RESULTS

In keeping with prior reports, AD use rapidly increased in the 1990s and early 2000s. However, the 2012 data suggest that these increases have slowed or perhaps even stopped in recent years. A post hoc examination of longitudinal data from the National Population Health Survey reinforced the impression of a levelling off in the use of these medications.

CONCLUSION

The frequency of AD use may now be stabilizing in the Canadian population. This emerging steady state may reflect a contemporary balance between the perceived need, perceived effectiveness, and acceptability of these medications in the general population.

Changing perceptions of mental health in Canada

OBJECTIVE

Epidemiologic studies typically assess mental health using diagnostic measures or symptom severity measures. However, perceptions are also important. The objective of our study was to evaluate trends in perceived mental health in Canada during the past 20 years using data collected in a series of surveys.

METHOD

Perceived mental health status, the stressfulness of most days, and perceived general health, have been repeatedly measured in national surveys. In our study, the resulting frequencies and 95% confidence intervals were calculated. Distress was also assessed in the same surveys with the Kessler 6 Psychological Distress Scale, and analyzed using mean scores and frequencies based on cut-points. Data synthesis used forest plots. Time trends were assessed using random effects meta-regression models.

RESULTS

No detectable changes in distress were found. Similarly, self-rated general health remained stable. However, over time, Canadians became slightly more likely to report that their mental health was merely fair or poor. Conversely, they have been progressively less likely to perceive that their lives are quite a bit or extremely stressful.

CONCLUSION

While these observations are ecological, the 2 trends may be related: distressing emotional experiences may increasingly be interpreted as evidence of a disturbance of mental health rather than a reaction to stressful circumstances. These changing perceptions should not be misinterpreted as an epidemic of poor mental health.

Perceived met and unmet health-care needs in a community population with multiple sclerosis

Community-based studies are required to accurately describe the supportive services needed by people with multiple sclerosis (MS). Characteristics that influence (or result from) care-seeking may introduce bias into other types of studies. The Participation and Activity Limitation Survey (PALS) was a post-census survey conducted by Statistics Canada in association with a 2006 national census. The PALS collected data from a sample of 22,513 respondents having health-related impairments according to their census forms. The survey collected self-reported diagnostic data and obtained ratings for items assessing impairment as well as perceived met and unmet needs for care and support. It identified 245 individuals with MS, leading to an estimated (weighted) population prevalence of 0.2% (200 per 100,000). As expected, those with MS reported more-severe health problems than did those with other types of disability, particularly in the areas of mobility, dexterity, and cognition; they were also more likely to report having multiple caregivers. People with MS also reported more unmet health-care needs than did those with other forms of disability, particularly with respect to meal preparation, housework, shopping, and chores. Despite their more negative health status and greater reliance on caregivers, people with MS reported participation in society comparable to that of people without MS. Thus, people with MS report greater needs than do people with other forms of health-related disability and utilize supportive services more often. However, they also report higher levels of unmet needs. The substantial needs of people with MS are only partially addressed by existing services.

Depression as a predictor of occupational transition in a multiple sclerosis cohort

In MS, transitions between working and not-working status may occur in association with depression. This can complicate patients' ability to promptly obtain disability support due to an expectation that their functioning will improve after the depression resolves, a viewpoint that sees depression assuming a role as a causal determinant of disability. In this study, prospective data were used to model the relationship between depressive symptoms and the transition out of employment. In unadjusted analyses, depression increased the risk of transition to non-working status, HR = 1.7 (95%CI 1.3-2.3). Adjustments for ambulation status, physical and mental quality of life composite scores and fatigue impact attenuated or eliminated the association. While depression commonly occurs around the time of occupational transitions in MS, it does not appear to be an independent or direct cause of such transitions.

Recreational physical activity ameliorates some of the negative impact of major depression on health-related quality of life

BACKGROUND

Major depressive episodes have a negative effect on health-related quality of life (HRQoL). The objective of this study was to determine whether recreational physical activity can ameliorate some of this negative impact.

METHODS

The data source for the study was the Canadian National Population Health Survey (NPHS). The NPHS is a longitudinal study that has collected data from a representative cohort of 15,254 community residents. Sixteen years of follow-up data are available. The NPHS included: an instrument to assess MDE (the Composite International Diagnostic Interview Short Form for Major Depression), an inventory of recreational activities (each associated with hours of participation and estimated metabolic expenditures), and a HRQoL instrument (the Health Utility Index, Mark 3, or HUI3). Proportional hazard and linear regression models were used in this study to determine whether MDE-related declines in HRQoL were lessened by participation in an active recreational lifestyle.

RESULTS

Consistent with expectation, major depression was associated with a significant decline in HRQoL over time. While no statistical interactions were observed, the risk of diminished HRQoL in association with MDE was reduced by physical activity. In a proportional hazards model, the hazard ratio for transition to poor HRQoL was 0.7 (95% CI: 0.6-0.8, p < 0.0001). In linear regression models, physical activity was significantly associated with more positive HRQoL (β = 0.019, 95% CI 0.004 to -0.034, p = 0.02).

CONCLUSION

Recreational physical activity appears to ameliorate some of the decline in HRQoL seen in association with MDE. Physical activity may be an effective tertiary preventive strategy for this condition.

Depressive episode characteristics and subsequent recurrence risk

BACKGROUND

Clinical practice guidelines increasingly recognize the heterogeneity associated with major depressive episodes (MDE), e.g. through strategies such as watchful waiting. However, the implications of episode heterogeneity for long-term prognosis have not been adequately explored.

METHODS

In this project, we used data from a Canadian longitudinal study to evaluate recurrence risks for MDE after an initial episode in the mid-1990s. This study collected data from a community cohort between 1994/1995 and 2008/2009 using biannual interviews. Characteristics of the index episode: syndromal versus sub-syndromal, duration of symptoms, and indicators of seriousness (activity restriction, high distress or suicidal ideation) were recorded. The ability of these variables to predict MDE recurrence was explored using proportional hazards modeling. Additional analyses using generalized estimating equations were used to assess robustness.

RESULTS

Even brief, sub-syndromal episodes not characterized by indicators of seriousness were associated with an increased risk of subsequent MDE. However, episodes meeting diagnostic criteria for MDE, those lasting longer than four weeks and those associated with indicators of seriousness were associated with much higher recurrence risk. Sub-syndromal episodes associated with these characteristics generally predicted subsequent MDE as strongly as the occurrence of MDE itself.

LIMITATIONS

The data source did not include assessment of all potentially relevant covariates. The assessment of MDE used an abbreviated instrument.

CONCLUSIONS

Brief sub-syndromal episodes of depression are not usually targets of acute treatment, but such episodes have implications for subsequent MDE risk. Episode characteristics identify a range of outcomes that have potential implications for long-term management.

Disability in a community population with MS with and without mental disorders

OBJECTIVE

Psychiatric conditions are known to have a detrimental impact on functioning and may therefore influence patterns of disability associated with MS. Population-based studies are needed to evaluate such interactions. The objective of this study was to describe the pattern of interaction of MS and mental disorders on health-related impairments.

METHODS

The Participation and Activity Limitation Survey (PALS) was a post-censual survey conducted by Statistics Canada in association with the 2006 Canadian Census. PALS collected detailed data from a random sample of n = 28,640 respondents with health-related impairments reported on their census form. The PALS interview collected self-reported diagnostic data and included scales to assess functioning and participation in society.

RESULTS

PALS identified 245 individuals with MS, leading to an estimated (weighted) population prevalence of 0.2% (200 per 100,000), consistent with other Canadian estimates. As expected, impaired agility, vision, communication, mobility, pain, and memory were strongly associated with MS. Mental disorders were also associated with impairment, but interactions between these conditions and MS were generally not evident.

CONCLUSIONS

Mental disorders are associated with a higher level of disability in MS but, with the exception of communication, there was no evidence of synergistic interaction between mental disorders and MS in contributing to health-related impairments.

Recall of recent and more remote depressive episodes in a prospective cohort study

BACKGROUND

In psychiatric epidemiology, symptoms are often assessed retrospectively. This raises concerns about the accuracy of the information recalled. In this study, we sought to examine the level of agreement between survey items assessing recent and more remote depressive episodes.

METHODS

Data from the Canadian National Population Health Survey (NPHS) were used. The NPHS is a prospective study following a representative cohort of household residents sampled in 1994 and 1995. Every 2 years, participants are administered the Composite International Diagnostic Interview Short Form for Major Depression (CIDI-SFMD). The 2004 NPHS interview also included items asking about past episodes of depression and diagnoses of depression done by health professionals. We used cross-tabulation and logistic regression to explore the relationship between these responses.

RESULTS

Approximately, 90% of respondents with CIDI-SFMD-defined major depressive episodes in the year preceding the 2004 interview also reported lifetime episodes or professional diagnoses of depression in 2004. However, responses to the 2004 lifetime items corresponded less closely to CIDI-SFMD results from the same individuals earlier in the longitudinal survey. Only 40.8% of respondents having the most recently identified episode in 1994 subsequently affirmed a past episode of depression in 2004.

CONCLUSIONS

Reporting of depressive episodes diminishes with time, suggesting that retrospective assessment of such episodes may be vulnerable to inaccuracy.

Persistent heavy smoking as risk factor for major depression (MD) incidence--evidence from a longitudinal Canadian cohort of the National Population Health Survey

BACKGROUND

Reports of bidirectional associations between smoking and major depression (MD) have been interpreted as providing evidence for confounding by shared-vulnerability factors (SV) that predispose individuals to both conditions. If this is true, then smoking cessation may not reduce the risk of MD. From clinical practice and public health perspectives, the long-term outcomes associated with smoking persistence and cessation are potentially important and deserve exploration. To this end, the 12-year risk of MD in persistent heavy smokers and abstainers who were former-heavy smokers with and without adjustment for potential confounders were compared.

METHODS

Follow-up data from the National Population Health Survey (NPHS) was used. Multinomial logistic (ML) models were fit to identify potential confounders. Using proportional hazard (PH) models, unadjusted and adjusted hazard ratios (HRs) for MD outcome were estimated for different smoking patterns.

RESULTS

The unadjusted HR relating the risk of MD among current-heavy versus former-heavy smokers was 4.3 (95% CI: 2.6-6.9, p < 0.001). Current-heavy smoking predicted onset of MD (HR = 3.1, 95% CI: 1.9-5.2, p < 0.001) even after adjustment for age, sex and stress - the main confounders. However, this was not the case for the never, former-light, and current-light categories. Evidence of decreased risk of MD among former-heavy relative to current-heavy smokers as function of smoking cessation maintenance time was also found.

CONCLUSIONS

Contrary to common beliefs about the benefits of smoking for mental health, our results suggest that current-heavy rather than ever-heavy smoking is a major determinant of MD risk and point towards the benefits of smoking cessation maintenance.

Weight gain in relation to major depression and antidepressant medication use

BACKGROUND

Previous studies have linked major depressive episodes (MDEs) to obesity. The association may be partially mediated by antidepressant medication use. In the current study we examine changes in weight and BMI in relation to MDE and antidepressant use in a general population cohort.

METHODS

Data from a Canadian longitudinal study, the National Population Health Survey (NPHS) were used. The NPHS has collected data from a community cohort since 1994 using interviews spaced two years apart. The NPHS includes the Composite International Diagnostic Interview Short Form for Major Depression (CIDI-SFMD). Self-reported height and weight are also recorded. Linear regression was used to describe associations between weight, BMI and MDE.

RESULTS

The pattern of weight change varied by age. Respondents under the age of 65 tended to gain weight over time, whereas those over the age of 65 tended to lose weight. Respondents in the younger category gained more weight if they had MDE or took antidepressant medications. However, the extent of weight gain was modest, those with MDE and those taking an antidepressant gaining an average of approximately 1 kg over 12 years of follow-up.

LIMITATIONS

The study used self-reported weight, which may be inaccurate. Measurements were made two years apart. The measure of MDE was an abbreviated diagnostic interview.

CONCLUSIONS

Both MDE and antidepressant medication use are associated with a modest increase in weight in people under 65. These results may be useful for physicians and other health professionals in planning dietary and weight-management regimens for depressed patients.

Major depression is a risk factor for shorter time to first cigarette irrespective of the number of cigarettes smoked per day: evidence from a National Population Health Survey

Introduction:

We assessed whether major depression (MD) predicts progression of nicotine dependence (ND) as measured by reduction in the time to first cigarette (TTFC) after waking and the roles of the number of cigarettes smoked per day (CPD) and stress as explanatory variables of this association.

Methods:

Ten years of follow-up data from the National Population Health Survey (NPHS) were used. The analyses were based on this nationally representative sample of the Canadian population who were over the age of 12 years in 1996 (n = 13,298). The NPHS included measures of MD and TTFC. Shorter TTFC was defined as TTFC within 5 min of waking. Heavy smoking (HS) was defined by smoking 20 or more CPD. Using proportional hazard models, unadjusted and adjusted hazard ratios (HRs) for shorter TTFC were estimated for those with and without MD.

Results:

The unadjusted HR for shorter TTFC among those with MD versus those without MD was 3.7 (95% CI: 2.6–5.3, p < .001). MD predicted onset of shorter TTFC even after adjustment for HS and tendency to smoke more under stress (HR: 1.7; 95% CI: 1.1–2.5, p = .02). When TTFC was defined using longer cutoffs (30 and 60 min), HS completely accounted for the effect of MD on TTFC onset.

Conclusions:

MD appears to be a risk factor for transition to shorter TTFC independent of effects of HS and the tendency to smoke more under stress. As MD is often modifiable, the above association points toward a preventive opportunity in relation to worsening of ND.

Estimates of the treated prevalence of bipolar disorders by mental health services in the general population: comparison of results from administrative and health survey data

Introduction

Informed provision of population mental health services requires accurate estimates of disease burden.

Methods

We estimated the treated prevalence of bipolar disorders by mental health services in the Calgary Zone, a catchment area in Alberta with a population of over one million. Administrative data in a central repository provides information of mental health care contacts for about 95% of publically funded mental health services. We compared this treated prevalence against self-reported data in the 2002 Canadian Community Health Survey: Mental Health and Well-Being (CCHS 1.2).

Results

Of the 63 016 individuals aged 18 years plus treated in the Calgary Zone in 2002–2008, 3659 (5.81%) and 1065 (1.70%) were diagnosed with bipolar I and bipolar II disorder, respectively. The estimated treated population prevalence of these disorders was 0.41% and 0.12%, respectively. We estimated that 0.44% to 1.17% of the Canadian population was being treated by psychiatrists for bipolar I disorder from CCHS 1.2.

Discussion

For bipolar I disorder the estimate based on local administrative data is close to the lower end of the health survey range. The degree of agreement in our estimates reinforces the utility of administrative data repositories in the surveillance of chronic mental disorders.

Estimates of the treated prevalence of bipolar disorders by mental health services in the general population: comparison of results from administrative and health survey data

INTRODUCTION

Informed provision of population mental health services requires accurate estimates of disease burden.

METHODS

We estimated the treated prevalence of bipolar disorders by mental health services in the Calgary Zone, a catchment area in Alberta with a population of over one million. Administrative data in a central repository provides information of mental health care contacts for about 95% of publically funded mental health services. We compared this treated prevalence against self-reported data in the 2002 Canadian Community Health Survey: Mental Health and Well-Being (CCHS 1.2).

RESULTS

Of the 63 016 individuals aged 18 years plus treated in the Calgary Zone in 2002-2008, 3659 (5.81%) and 1065 (1.70%) were diagnosed with bipolar I and bipolar II disorder, respectively. The estimated treated population prevalence of these disorders was 0.41% and 0.12%, respectively. We estimated that 0.44% to 1.17% of the Canadian population was being treated by psychiatrists for bipolar I disorder from CCHS 1.2.

DISCUSSION

For bipolar I disorder the estimate based on local administrative data is close to the lower end of the health survey range. The degree of agreement in our estimates reinforces the utility of administrative data repositories in the surveillance of chronic mental disorders.

Pharmacoepidemiology of benzodiazepine and sedative-hypnotic use in a Canadian general population cohort during 12 years of follow-up

OBJECTIVE

benzodiazepines (BDZs) and similar sedative-hypnotics (SSHs) can have both beneficial and adverse effects. Clinical practice guidelines indicate that the course of treatment should usually be brief (a few weeks), but patients often take these medications for longer periods of time. We hypothesized that treatment with antidepressants (ADs) would be associated with a shorter duration of SSHs use as mood and anxiety disorders may underlie the symptoms usually targeted by BDZ treatment.

METHOD

our study used data from a Canadian longitudinal general health study, the National Population Health Survey, which has collected data since 1994. Data are currently available to 2006. At each interview, all medications taken in the preceding 2 days are recorded. In our study, we used proportional hazard models to describe patterns of initiation and discontinuation of these medications in the general population.

RESULTS

at each interview, the frequency of BDZ-SSH use was 2% to 3%. About 1% of the population initiated use in each 2-year follow-up period. Contrary to expectation, taking ADs predicted initiation of BDZ-SSHs, but not discontinuation.

CONCLUSIONS

unexpectedly, respondents taking ADs had a higher frequency of new BDZ-SSH use. AD use may be a marker for depression severity or comorbidity, such that the observed results may be an artifact of confounding by these factors. Irrespective of etiology, initiation of AD treatment does not appear to negate the risk of long-term BDZ-SSH use.

Reciprocal effects of social support in major depression epidemiology

Background:

The clinical course and epidemiology of major depressive episodes (MDEs) may be influenced by reciprocal interactions between an individual and the social environment. Epidemiological data concerning these interactions may assist with anticipating the clinical needs of depressed patients.

Methods:

The data source for this study was a Canadian longitudinal study, the National Population Health Survey (NPHS), which provided 8 years of follow-up data. The NPHS interview included a brief diagnostic indicator for MDE, the Composite International Diagnostic Interview Short Form for Major Depression (CIDI-SFMD). The NPHS interview also incorporated the Medical Outcomes Study Social Support Scale (MOSSS) and a set of relevant demographic and health-related measures. The MOSSS assesses total social support and four specific dimensions of social support. Hazard ratios (HR) were used to quantify associations in the longitudinal data.

Results:

Lower quartile total social support ratings predicted MDE incidence: the HR adjusted for age and sex was 1.9 (95% CI 1.6 – 2.2). Lower quartile ratings in specific social support dimensions yielded similar HRs. MDE was associated with emergence of lower-quartile affection social support (age and sex adjusted HR 1.3, 95% CI 1.1 – 1.7), but other aspects of social support were not consistently associated with MDE.

Conclusions:

Low social support appears to be a robust risk factor for MDE and can be used to identify persons at higher risk of MDE. Evidence that MDE has a negative effect on social support was weaker and was restricted to affection social support.

Predictors of the longitudinal course of major depression in a Canadian population sample

OBJECTIVE

Most psychiatric epidemiologic studies have used cross-sectional methods, resulting in a lack of information about the longitudinal course of depressive disorders. The objective of our study was to describe the longitudinal epidemiology of major depressive episodes (MDEs) in a Canadian sample using data from the National Population Health Survey (NPHS).

METHODS

The NPHS started data collection in 1994 and has evaluated past-year MDE using repeat interviews of the same cohort every 2 years since then. In our study, we examined the number of weeks depressed during years when MDEs occurred, the proportion of respondents having MDEs at consecutive cycles, and MDE counts during follow-up.

RESULTS

A sizable proportion of MDEs were brief: about one-half of respondents with past-year MDE reported 8 or fewer weeks of depression during that year. Less than 10% reported that they were depressed for the entire year. However, a larger proportion (19.1%) fulfilled criteria for MDE on consecutive interview cycles, suggesting either persistence or rapid recurrence. The mean number of detected MDEs among those with at least 1 detected MDE up to 2006 was 2. Positive family history, evidence of comorbidity, negative cognitive style, stress, pain, and smoking were associated with a more negative course.

CONCLUSIONS

The longitudinal course of MDE in the general population is heterogeneous, including a mixture of brief and more protracted MDEs. Many risk factors for MDE are also associated with a negative course, exceptions being (younger) age and sex. These epidemiologic observations may assist with identification of patients requiring more intensive management in clinical practice.

Frequency of antidepressant use in relation to recent and past major depressive episodes

OBJECTIVE

There has been a trend toward increasing antidepressant (AD) use in recent decades. We used data from the National Population Health Survey (NPHS) to determine whether this trend is continuing and to provide updated estimates of the frequency of use.

METHODS

The NPHS is a longitudinal general health survey that began collecting data in 1994. The NPHS evaluates past-year major depressive episodes (MDEs) using a brief diagnostic instrument. At each biannual interview (from 1994 to 2006) current medication use is recorded. We estimated the frequency with which ADs were taken by respondents (aged 12 years and older) with and without past-year MDEs. These frequencies were cross-tabulated by sex, year of interview, and the reported duration of symptoms.

RESULTS

ADs are taken by about 5.4% of the household population at any point in time. Most respondents taking ADs did not report past-year MDEs but 63.9% of respondents taking ADs in the absence of past-year episodes reported previous episodes or being diagnosed by a health professional with depression. This pattern is consistent with long-term treatment for relapse prevention. The overall frequency of use of ADs is increasing only in respondents without past-year episodes.

CONCLUSIONS

AD use among community residents with past-year MDEs is no longer increasing. The continued increase in the overall frequency of use may point toward broadening indications for AD treatment and may indicate that people are taking these medications for longer periods of time.

The relationship between major depression and marital disruption is bidirectional

BACKGROUND

Marital status is important to the epidemiology of psychiatric disorders. In particular, the high prevalence of major depression in individuals with separated, divorced, or widowed status has been well documented. However, the literature is divided as to whether marital disruption results in major depression and/or vise versa. We examined whether major depression influences changes of marital status, and, conversely, whether marital status influences the incidence of this disorder.

METHODS

We employed data from the longitudinal Canadian National Population Health Survey (1994-2004), and proportional hazards models with time-varying covariates.

RESULTS

Major depression had no effect on the proportion of individuals who changed from single to common-law, single to married, or common-law to married status. In contrast, exposure to depression doubled the proportion of transitions from common-law or married to separated or divorced status (HR=2.0; 95% CI 1.4-2.9 P<0.001). Conversely an increased proportion of nondepressed individuals with separated or divorced status subsequently experienced major depression (hazard ratio, HR=1.3; 95% CI 1.0-1.5 P=0.04).

CONCLUSION

The high prevalence of major depression in separated or divorced individuals is due to both an increased risk of marital disruption in those with major depression, and also to the higher risk of this disorder in those with divorced or separated marital status. Thus a clinically significant interplay exists between major depression and marital status. Clinicians should be aware of the deleterious impact of major depression on marital relationships. Proactive management of marital problems in clinical settings may help minimize the psycho-social "scar" that is sometimes associated with this disorder.

Prospective evaluation of the effect of major depression on working status in a population sample

OBJECTIVE

Numerous surveys have reported associations between major depressive episodes (MDEs) and occupational status, but cross-sectional studies cannot quantify the risks of employment transitions nor clarify their temporal direction. The goal of our study was to estimate the impact of MDE on subsequent employment status in a longitudinal community cohort.

METHODS

Data from the National Population Health Survey (NPHS) were used. Proportional hazard models and logistic regression were employed to evaluate the effect of MDE on working status during the 1994 to 2004 interval among respondents who reported working at a job or business at baseline.

RESULTS

MDE was associated with an increased risk of movement to nonworking status. People aged 26 to 45 years with MDEs have more than double the risk of this transition (HR = 2.6; 95% CI 1.8 to 3.6, P < 0.001). The probability of transition to nonworking status was higher, but the relative effect was smaller in people aged 46 to 65 years (HR = 1.2; 95% CI 0.7 to 2.0, P = 0.47). Retirement or perceived lack of availability of work did not contribute to the association.

CONCLUSIONS

MDE is associated with an elevated risk of transition from working to nonworking status, especially in people aged 26 to 45 years.

A longitudinal community study of major depression and physical activity

BACKGROUND

The objective of this study was to determine whether major depressive episodes (MDEs) are associated transitions between active and inactive recreational activity patterns.

METHODS

The data source was the Canadian National Population Health Survey (NPHS). The NPHS included a brief instrument to assess MDEs and collected data on participation in recreational activities. In order to meaningfully categorize participation in recreational activities, the participation data was translated into overall estimated metabolic energy expenditure. A threshold of 1.5 kcal/kg per day was used to distinguish between active and inactive activity patterns. Proportional hazards models were used to compare the incidence of inactivity in initially active respondents with and without MDE and to compare the frequency of becoming active among initially inactive respondents with and without MDE.

RESULTS

For active respondents with MDE, an elevated risk of transition into an inactive pattern was observed [adjusted hazard ratio (HR)=1.6; 95% CI 1.2-1.9]. However, MDE did not affect the probability of moving from an inactive to an active lifestyle (adjusted HR=1.0; 95% CI 0.78-1.19).

CONCLUSIONS

Major depressive episodes are associated with an increased risk of transition from an active to an inactive pattern of activity.

Major depression, antidepressant medication and the risk of obesity

BACKGROUND

Cross-sectional studies have reported an association between major depressive episode (MDE) and obesity. The objective of this longitudinal analysis was to determine whether MDE increase the risk of becoming obese over a 10-year period.

METHOD

We used data from the Canadian National Population Health Survey (NPHS), a longitudinal study of a representative cohort of household residents in Canada. The incidence of obesity, defined as a body mass index (BMI) of > or =30, was evaluated in respondents who were 18 years or older at the time of a baseline interview in 1994. MDE was assessed using a brief diagnostic instrument.

RESULTS

The risk of obesity was not elevated in association with MDE, either in unadjusted or covariate-adjusted analyses. The strongest predictor of obesity was a BMI in the overweight (but not obese) range. Effects were also seen for (younger) age, (female) sex, a sedentary activity pattern, low income and exposure to antidepressant medications. Unexpectedly, significant effects were seen for serotonin-reuptake-inhibiting antidepressants and venlafaxine, but neither for tricyclic antidepressants nor antipsychotic medications.

CONCLUSIONS

MDE does not appear to increase the risk of obesity. The cross-sectional associations that have been reported, albeit inconsistently, in the literature probably represent an effect of obesity on MDE risk. Pharmacologic treatment with antidepressants may be associated with an increased risk of obesity, and strategies to offset this risk may be useful in clinical practice.

The effect of major depression on participation in preventive health care activities

BACKGROUND

The objective of this study was to determine whether major depressive episodes (MDE) contribute to a lower rate of participation in three prevention activities: blood pressure checks, mammograms and Pap tests.

METHODS

The data source for this study was the Canadian National Population Health Survey (NPHS), a longitudinal study that started in 1994 and has subsequently re-interviewed its participants every two years. The NPHS included a short form version of the Composite International Diagnostic Interview (CIDI-SF) to assess past year MDE and also collected data on participation in preventive activities. Initially, we examined whether respondents with MDE in a particular year were less likely to participate in screening during that same year. In order to assess whether MDE negatively altered the pattern of participation, those successfully screened at the baseline interview in 1994 were identified and divided into cohorts depending on their MDE status. Proportional hazard models were used to quantify the effect of MDE on subsequent participation in screening.

RESULTS

No effect of MDE on participation in the three preventive activities was identified either in the cross-sectional or longitudinal analysis. Adjustment for a set of relevant covariates did not alter this result.

CONCLUSION

Whereas MDE might be expected to reduce the frequency of participation in screening activities, no evidence for this was found in the current analysis. Since people with MDE may contact the health system more frequently, this may offset any tendency of the illness itself to reduce participation in screening.

Allergies and major depression: a longitudinal community study

Background

Cross-sectional studies have reported associations between allergies and major depression but in the absence of longitudinal data, the implications of this association remain unclear. Our goal was to examine this association from a longitudinal perspective.

Methods

The data source was the Canadian National Population Health Survey (NPHS). This study included a short form version of the Composite International Diagnostic Interview (CIDI-SF) to assess major depression and also included self report items for professionally diagnosed allergies of two types: non-food allergies and food allergies. A longitudinal cohort was followed between 1994 and 2002. Proportional hazards models for grouped time data were used to estimate unadjusted and adjusted hazard ratios.

Results

A slightly increased incidence of non-food allergies in respondents with major depression was observed: adjusted hazard ratio 1.2 (95% 1.0 – 1.5, p = 0.046). Some evidence for an increased incidence of major depression in association with non-food allergies was found in unadjusted analyses, but the association did not persist after multivariate adjustment. Food allergies were not associated with major depression incidence, nor was major depression associated with an increased incidence of food allergies.

Conclusion

Findings from the present study support the idea that major depression is associated with an increased risk of developing non-food allergies. An effect in the opposite direction could not be confirmed. The observed effect may be due to shared genetic factors, epigenetic factors, or immunological changes that occur during depression.

Major depression as a risk factor for chronic disease incidence: longitudinal analyses in a general population cohort

OBJECTIVE

Cross-sectional studies have consistently reported associations between major depression (MD) and chronic medical conditions. Such studies cannot clarify whether medical conditions increase the risk for MD or vice versa. The latter possibility has received relatively little attention in the literature. In this study, we evaluate the incidence of several important chronic medical conditions in people with and without MD.

METHOD

The data source was the Canadian National Population Health Survey (NPHS). The NPHS included the Composite International Diagnostic Interview Short Form to assess past-year major depressive episodes. The NPHS also collected self-report data about professionally diagnosed long-term medical conditions. A longitudinal cohort was interviewed every 2 years between 1994 and 2002. Proportional hazards models were used to compare the incidence of chronic conditions in respondents with and without MD and to produce age-, sex- and covariate-adjusted estimates of the hazard ratios.

RESULTS

The adjusted hazard ratios associated with MD at baseline interview were elevated for several long-term medical conditions: heart disease (1.7), arthritis (1.9), asthma (2.1), back pain (1.4), chronic bronchitis or emphysema (2.2), hypertension (1.7) and migraines (1.9). The incidences of cataracts and glaucoma, peptic ulcers and thyroid disease were not higher in respondents with MD.

CONCLUSION

A set of conditions characterized particularly by pain, inflammation and/or autonomic reactivity has a higher incidence in people with MD.

Clinical correlates of CES-D depressive symptom ratings in an MS population

OBJECTIVE

In multiple sclerosis (MS), depression rating scales may be used as case-finding instruments for depressive disorders, but depressive symptom ratings may have clinical implications beyond their case-finding role. The objective of this analysis was to explore this possibility by carrying out descriptive analyses of symptom ratings obtained using the Center for Epidemiological Studies Depression Rating Scale (CES-D) in an MS clinic population.

METHOD

The analysis used cross-sectional baseline data collected from 589 subjects enrolled in a prospective cohort study. Data collection included demographic and clinical information including Extended Disability Status Scale ratings, a 54-item MS Quality of Life Scale and the Fatigue Impact Scale.

RESULTS

Across a spectrum of CES-D scores, correlations with other health indicators were observed. Depressive symptoms were higher in more disabled subjects. CES-D scores were correlated with the emotional well-being dimension of quality of life and with a social fatigue impact dimension. Alternative scoring of the CES-D had a negligible impact on the pattern of correlation.

CONCLUSIONS

CES-D ratings appear to be interpretable beyond the traditional yes/no categorization used in case finding. CES-D ratings are predictive of other clinical parameters in domains relevant to mental health.

Medication use and major depressive syndrome in a community population

A variety of medications have been reported to cause depression as a side effect. This study evaluated cross-sectional associations between a variety of medications and a syndrome resembling major depression. A sample of 2,542 subjects were selected using the Mitofsky-Waksberg random digit dialing (RDD) procedure. Major depression was evaluated using a short form version of the Composite International Diagnostic Interview (CIDI). Current medication use was recorded during the same telephone interview. Statistical methods accounting for clustering and unequal selection probabilities were employed. Most medications were not associated with major depression: these included beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, lipid-lowering agents, digoxin, and diuretics. Calcium channel blockers were significantly associated with major depression, but only in a subset of young subjects, and these tended to be seriously ill individuals taking multiple medications. Opiate analgesics were associated with major depression, but only in male subjects. Corticosteroids were significantly associated with major depression in a logistic regression model that adjusted for age and gender. The cross-sectional nature of this study precludes causal inference about the observed associations. With the exception of the association of major depression with corticosteroid use, convincing associations with other medications were not observed. It is possible that medication-induced depressive episodes lead to changes in exposure status (such as discontinuation of the offending medications) such that the associations are not apparent in cross-sectional data. If this interpretation is correct, these data suggest that the problem of medication-induced depression is being managed effectively at the clinical level and is not a substantial public health problem.