Dataset Information

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

ABSTRACT: 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.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.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.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.

SUBMITTER: Wiens K

PROVIDER: S-EPMC5302107 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

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

Wiens Kathryn K Williams Jeanne V A JV Lavorato Dina H DH Bulloch Andrew G M AG Patten Scott B SB

Canadian journal of psychiatry. Revue canadienne de psychiatrie 20160711 1

<h4>Objective</h4>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.<h4>Method</h4>A series of 11 Canadian national cross-sectional studies were examined from 2000 to 2014, providing ...[more]

PMID: 27407074

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Project description:Objective: Clinically, it is very difficult to distinguish between major depressive disorder (MDD) and bipolar disorder (BD) in the period of depression. Increasing evidence shows that the insula plays an important role in depression. We aimed to compare the resting-state functional connectivity (rsFC) of insular subregions in patients with MDD and BD in depressive episodes (BDD), who had never experienced manic or hypomanic episodes when they were scanned to identify biomarkers for the identification of two diseases. Methods: We recruited 21 BDD patients, 40 MDD patients and 70 healthy controls (HC). Resting-state functional magnetic resonance imaging (rs-fMRI) was performed. BDD patients had never had manic or hypomanic episodes when they were scanned, and the diagnoses were determined by follow-up. We divided the insula into three parts including the ventral anterior insular cortex (v-AIN), dorsal anterior insular cortex (d-AIN), and posterior insula (PI). The insular-based rsFC was compared among the three groups, and an analysis of the correlation between the rsFC value and Hamilton depression and anxiety scales was carried out. Results: BDD and MDD patients demonstrated decreased rsFC from the v-AIN to the left superior/middle frontal gyrus compared with the HC group. Versus MDD and HC groups, BDD patients exhibited decreased rsFC from the v-AIN to the area in the left orbital frontal gyrus and left superior temporal gyrus (included temporal pole), from the PI to the right lateral postcentral gyrus and from all three insular subregions to the somatosensory and motor cortex. Meanwhile, a correlation between the rsFC value of the PI-right lateral postcentral gyrus and anxiety score was observed in patients. Conclusion: Our findings show BDD and MDD patients have similar decreases in insular connectivity in the dorsal lateral frontal regions, and BDD patients have specific decreased insular connectivity, especially in the somatosensory and motor cortex, which may be used as imaging evidence for clinical identification.

Project description:ObjectivesComposite diagnostic criteria alone are likely to create and introduce biases into diagnoses that subsequently have poor relationships with input symptoms. This study aims to understand the relationships between the diagnoses and the input symptoms, as well as the magnitudes of biases created by diagnostic criteria and introduced into the diagnoses of mental illnesses with large disease burdens (major depressive episodes, dysthymic disorder, and manic episodes).SettingsGeneral psychiatric care.ParticipantsWithout real-world data available to the public, 100 000 subjects were simulated and the input symptoms were assigned based on the assumed prevalence rates (0.05, 0.1, 0.3, 0.5 and 0.7) and correlations between symptoms (0, 0.1, 0.4, 0.7 and 0.9). The input symptoms were extracted from the diagnostic criteria. The diagnostic criteria were transformed into mathematical equations to demonstrate the sources of biases and convert the input symptoms into diagnoses.Primary and secondary outcomesThe relationships between the input symptoms and diagnoses were interpreted using forward stepwise linear regressions. Biases due to data censoring or categorisation introduced into the intermediate variables, and the three diagnoses were measured.ResultsThe prevalence rates of the diagnoses were lower than those of the input symptoms and proportional to the assumed prevalence rates and the correlations between the input symptoms. Certain input or bias variables consistently explained the diagnoses better than the others. Except for 0 correlations and 0.7 prevalence rates of the input symptoms for the diagnosis of dysthymic disorder, the input symptoms could not fully explain the diagnoses.ConclusionsThere are biases created due to composite diagnostic criteria and introduced into the diagnoses. The design of the diagnostic criteria determines the prevalence of the diagnoses and the relationships between the input symptoms, the diagnoses, and the biases. The importance of the input symptoms has been distorted largely by the diagnostic criteria.

Project description:ImportanceThe neuroinflammatory hypothesis of major depressive disorder is supported by several main findings. First, in humans and animals, activation of the immune system causes sickness behaviors that present during a major depressive episode (MDE), such as low mood, anhedonia, anorexia, and weight loss. Second, peripheral markers of inflammation are frequently reported in major depressive disorder. Third, neuroinflammatory illnesses are associated with high rates of MDEs. However, a fundamental limitation of the neuroinflammatory hypothesis is a paucity of evidence of brain inflammation during MDE. Translocator protein density measured by distribution volume (TSPO VT) is increased in activated microglia, an important aspect of neuroinflammation.ObjectiveTo determine whether TSPO VT is elevated in the prefrontal cortex, anterior cingulate cortex (ACC), and insula in patients with MDE secondary to major depressive disorder.Design, setting, and participantsCase-control study in a tertiary care psychiatric hospital from May 1, 2010, through February 1, 2014. Twenty patients with MDE secondary to major depressive disorder and 20 healthy control participants underwent positron emission tomography with fluorine F 18-labeled N-(2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide ([18F]FEPPA). Patients with MDE were medication free for at least 6 weeks. All participants were otherwise healthy and nonsmokers.Main outcomes and measuresValues of TSPO VT in the prefrontal cortex, ACC, and insula.ResultsIn MDE, TSPO VT was significantly elevated in all brain regions examined (multivariate analysis of variance, F15,23 = 4.5 [P = .001]). The magnitude of TSPO VT elevation was 26% in the prefrontal cortex (mean [SD] TSPO VT, 12.5 [3.6] in patients with MDE and 10.0 [2.4] in controls), 32% in the ACC (mean [SD] TSPO VT, 12.3 [3.5] in patients with MDE and 9.3 [2.2] in controls), and 33% in the insula (mean [SD] TSPO VT, 12.9 [3.7] in patients with MDE and 9.7 [2.3] in controls). In MDE, greater TSPO VT in the ACC correlated with greater depression severity (r = 0.63 [P = .005]).Conclusions and relevanceThis finding provides the most compelling evidence to date of brain inflammation, and more specifically microglial activation, in MDE. This finding is important for improving treatment because it implies that therapeutics that reduce microglial activation should be promising for MDE. The correlation between higher ACC TSPO VT and the severity of MDE is consistent with the concept that neuroinflammation in specific regions may contribute to sickness behaviors that overlap with the symptoms of MDE.

Dataset Information

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

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

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