Norbert Schmitz

McGill University, Montréal, Quebec, Canada

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Publications (178)566.8 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: AimDuration of untreated psychosis (DUP) has been associated with negative symptoms in several studies; however, longitudinal findings have been inconsistent. No previous study has accounted for active psychosis after presentation, although this could impact on outcomes in a manner similar to DUP.Methods We measured Scale for the Assessment of Positive Symptoms at frequent intervals during the 12 months after initial presentation to determine the active psychosis duration for 230 individuals with first-episode psychosis. This duration was added to DUP prior to presentation to create a new variable, duration of active psychosis (DAP). Negative symptoms were divided into expressivity and motivation/pleasure domains as measured by Scale for the Assessment of Negative Symptoms (SANS). The relationship of DUP and DAP with negative symptoms at 24-month follow up was determined and confounders controlled for using regression analysis.ResultsWhen DUP and DAP were compared as binary variables with long and short groups, 25.2% of individuals had differing category membership. DAP had a significant uncorrected association with both expressivity domain and motivation/pleasure domains at 24 months; however, relationship with DUP was not significant. DAP remained a significant predictor of 24-month expressivity domain after controlling for potential confounders.Conclusions Active psychosis after presentation is substantial, which is a limitation of DUP studies if active psychosis is considered as the key factor within DUP. DAP is a better predictor of negative symptoms than DUP at 2-year follow up, which suggests this concept requires further research.
    Early Intervention in Psychiatry 02/2015; · 1.65 Impact Factor
  • Matthew Clyde, Kimberley J. Smith, Geneviève Gariépy, Norbert Schmitz
    Journal of Diabetes 01/2015; · 2.94 Impact Factor
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    ABSTRACT: The inflammatory marker C-reactive protein (CRP) is associated with depression. We examined the directional relations between CRP and symptoms of depression among older adults. The sample consisted of 3397 participants from the English Longitudinal Study of Ageing, a prospective study of community-dwelling older adults. CRP and depressive symptoms were measured at baseline and follow-up. A high CRP level was dichotomized as >3 mg/L. Elevated depressive symptomatology was defined as ≥4 using the 8-item Center for Epidemiologic Studies Depression Scale. Logistic regressions computed the association between high CRP levels at baseline with elevated depressive symptoms at follow-up, and vice versa. After adjusting for baseline depressive symptoms, baseline high CRP levels were associated with subsequent elevated symptoms of depression (OR = 1.49; 95% CI, 1.19-1.88). This relationship was no longer significant after simultaneous adjustments for metabolic and health variables. In the other direction, after adjusting for baseline CRP levels, baseline elevated depressive symptoms was not associated with subsequent high CRP levels (OR = 1.12; 95% CI, 0.88-1.42). High CRP levels at baseline are related to elevated depressive symptomatology at follow-up due to clinical factors. No association was found in the opposite direction. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.
    International Journal of Geriatric Psychiatry 12/2014; · 3.09 Impact Factor
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    ABSTRACT: The neighbourhood environment could play a role in the risk of depression in adults and those with a chronic illness. We investigated the effects of a range of neighbourhood characteristics on the 10-year risk of depression in a representative sample of 9026 Canadian adults and subsamples with a chronic condition. Characteristics of neighbourhoods were not significantly related to the risk of depression in the general sample and subsamples with a chronic condition. However, residing near a park was significantly associated with a lower risk of depression for people living in crowded households, and having a local health service nearby was protective for those living in materially deprived neighbourhoods. Living in a neighbourhood that was both socially advantaged and offered cultural services was also associated with lower risk of depression. Additional research is needed for smaller effect size detection. Future intervention research is warranted for health policy recommendations.
    Health & Place 11/2014; · 2.44 Impact Factor
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    ABSTRACT: Background Depression is a common co-illness in people with diabetes. Evidence suggests that the neighbourhood environment impacts the risk of depression, but few studies have investigated this effect in those with diabetes. We examined the effect of a range of neighbourhood characteristics on depression in people with Type 2 diabetes.Methods This cohort study used five waves of data from 1298 participants with Type 2 diabetes from the Diabetes Health Study (2008–2013). We assessed depression using the Patient Health Questionnaire. We measured neighbourhood deprivation using census data; density of services using geospatial data; level of greenness using satellite imagery; and perceived neighbourhood characteristics using survey data. The effect of neighbourhood factors on risk of depression was estimated using survival analysis, adjusting for sociodemographic variables. We tested effect modification by age, sex and socio-economic characteristics using interaction terms.ResultsMore physical activity facilities, cultural services and a greater level of greenness in the neighbourhood were associated with a lower risk of depression in our sample, even after adjusting for confounders. Material deprivation was associated with increased risk of depression, particularly in participants who were older or retired.Conclusions Characteristics of neighbourhoods were associated with the risk of depression in people with Type 2 diabetes and there were vulnerable subgroups within this association. Clinicians are encouraged to consider the neighbourhood environment of their patients when assessing the risk of depression. Future intervention research is need for health policy recommendations.This article is protected by copyright. All rights reserved.
    Diabetic Medicine 11/2014; · 3.24 Impact Factor
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    ABSTRACT: Objectives : Raised levels of C-reactive protein (CRP), an inflammatory biomarker, and depressive symptoms are both independently linked to risk of diabetes. The purpose of this study was to assess the joint association of CRP and depressive symptomatology with diabetes incidence in a representative sample of English people ≥ 50 years old. Method : Data were from the English Longitudinal Study of Ageing, a prospective study of community-dwelling older adults. The sample was comprised of 4955 participants without self-reported doctor-diagnosed diabetes at baseline. High CRP level was dichotomized as > 3 mg/L. Elevated depressive symptomatology was defined as ≥ 4 using the 8-item Center for Epidemiologic Studies Depression Scale. Incident diabetes was determined based on newly self-reported doctor-diagnosed diabetes. Cox proportional hazard regressions were used to examine the association between CRP and depressive symptoms with incidence of type 2 diabetes. Results : During approximately 63.2 months of follow-up, 194 participants reported diabetes diagnosis. After adjustment for socio-demographics, lifestyle behaviours, clinical factors, and BMI, the hazard ratio for diabetes was 1.63 (95% CI 0.88-3.01) for people with elevated depressive symptoms only, 1.43 (95% CI 0.99-2.07) for people with high CRP only, and 2.03 (95% CI 1.14-3.61) for people with both high CRP and elevated depressive symptoms. Conclusion : The presence of both high CRP levels and elevated depressive symptoms was associated with risk of diabetes. Further investigation into this relationship could aid in understanding the mechanisms underlying inflammation, depression, and diabetes.
    Journal of Psychosomatic Research 09/2014; · 2.84 Impact Factor
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    ABSTRACT: The problems of obesity and depression in type 2 diabetes mellitus are well documented, yet the role of weight cycling in relation to these 2 chronic conditions has not been examined. The study objective was to determine whether weight cycling predicts the development of depressive symptoms in the course of 1 year.
    Canadian Journal of Diabetes 07/2014; · 0.46 Impact Factor
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    ABSTRACT: Interventions aimed at influencing specific pathways to care may reduce the duration of untreated psychosis (DUP). The purpose of this study was to reduce delay in referral to an early intervention service following first contact for help seeking for psychosis in a defined urban catchment area.
    Social Psychiatry and Psychiatric Epidemiology 06/2014; · 2.58 Impact Factor
  • Diabetes Care 06/2014; 37(6):e146-7. · 8.57 Impact Factor
  • Kimberley J. Smith, Norbert Schmitz
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    ABSTRACT: Objective There is a well-documented association between depression and disability in people with diabetes. However less is known about the possible association of co-occurring anxiety on these associations. The objective of this study was to assess the association of elevated anxiety and/or depression symptoms with functional disability and frequent disability days in a community sample with type 2 diabetes. Methods Participants were 1,999 people with diabetes who completed the baseline portion of the Evaluation of Diabetes Treatment study. Functional disability was assessed using the World Health Organisation Disability Assessment Schedule II. Frequent disability days were assessed using a cutoff of ≥ 14 on a question assessing past month functional disability from the Healthy Days Core Module. Depression and Anxiety were assessed with the Patient Health Questionnaire and General Anxiety Questionnaire with cutoffs of ≥ 10 applied to create groups. Additional questions examined diabetes complications, chronic conditions and sociodemographic characteristics. Results Fully-adjusted logistic regression analyses demonstrated an increased likelihood of reporting functional disability for all groups with high anxiety and/or depressive symptoms. Groups with high depressive symptoms with and without high anxiety symptoms were also more likely to report frequent disability days. Conclusions Results indicate that elevated anxiety and depression symptoms are important factors associated with increased functional disability and frequent disability days in people with diabetes.
    Psychosomatics 06/2014; · 1.67 Impact Factor
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    ABSTRACT: To examine the association between physical inactivity and anxiety symptoms in a community-based sample of men and women with type 2 diabetes mellitus.
    Canadian Journal of Diabetes 05/2014; · 0.46 Impact Factor
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    ABSTRACT: The aim of this study was to assess differences in cardiovascular risk and performance of self-care activities in people who rated their diabetes control as good or poor.A sub-sample of 77 participants who took part in the Evaluation of Diabetes Treatment telephone interview were invited into a clinic to complete a series of laboratory examinations. Self-rated diabetes control was validated using the following laboratory markers: HbA1c, total cholesterol/HDL cholesterol ratio and LDL cholesterol. Differences in blood pressure and BMI were also assessed. Finally, all participants also completed the Summary of Self-Care activities questionnaire.Those people who rated their diabetes control as fair or poor had a significantly higher BMI, HbA1c levels, total cholesterol/HDL-cholesterol ratio and systolic blood pressure. When asked about self-care activities in the past week, those people who reported their diabetes control was fair/poor had spent significantly fewer days following a general diet and exercising.People with poor self-rated diabetes control have unfavourable cardiovascular risk and decreased performance of self-care activities.
    Experimental and Clinical Endocrinology & Diabetes 03/2014; · 1.76 Impact Factor
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    ABSTRACT: To investigate the stability and longitudinal association between depression and smoking status within a community sample with type-2 diabetes, while controlling for socio-demographic and disease related variables. Adults with type-2 diabetes were recruited and agreed to be followed-up via random digit dialing for the Montreal Diabetes Health Study (DHS). At baseline, 1618 individuals were classified as never, former, light (≤10 cigarettes a day) and moderate-heavy (11+ cigarettes a day); Depression was assessed using the Patient Health Questionnaire-9 and individuals were classified as none vs. depression syndrome. Generalized Estimating Equations were used to test the association between depression syndrome and current smoking status, while controlling for other demographic and health related variables. Prevalence rates of smoking and depression showed mild-substantial agreement over time; Depression syndrome was significantly associated with moderate-heavy smoking in the fully adjusted model using cross-sectional (all 4 waves, OR = 1.46, 95% CI 1.08-1.99, p < 0.05) and longitudinal (controlling for depression at baseline; OR = 1.54, 95% CI 1.02-2.31, p < 0.05) data. Smoking and depression prevalence rates appear to be stable over time in our community sample with type-2 diabetes. Moderate-heavy smoking is strongly associated with elevated depression, both in cross-sectional and longitudinal models; persistent moderate-heavy smokers may are at increased risk of both physical and mental health complications. This burden is even greater for those with type-2 diabetes.
    Journal of Diabetes 02/2014; · 2.94 Impact Factor
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    ABSTRACT: This realist review seeks to elucidate the modifiable causal pathways through which neighborhoods affect depressive symptoms in adult populations. Studies were identified using Medline, PubMed, PsycInfo, Geobase, and Web of Science databases, and chosen using reproducible selection criteria and systematic critical appraisal. A total of 14 longitudinal studies, published between 2003 and 2011, were included. Eleven of the articles observed a significant relationship between depression and at least one of the following neighborhood-level variables: neighborhood deprivation, disorder, instability, and social ties. Proposed modifiable pathways linking neighborhood characteristics and depression include: (1) the level of neighborhood-based stress that is placed on individuals, (2) the formation and strength of protective and supportive social networks, (3) the level of resiliency to negative affectivity and stress, (4) the perceptions of the esthetic and form of residential space, and (5) the sense of control and agency in place of residence. These pathways represent potential areas for future research and intervention. Further research requires a more systematic use of longitudinal design and a diversity of physical and social environmental measures. Interventions aimed at improving affective resiliency need to be tested.
    Social Psychiatry 01/2014; · 2.05 Impact Factor
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    ABSTRACT: Prediction algorithms are useful for making clinical decisions and for population health planning. However, such prediction algorithms for first onset of major depression do not exist. The objective of this study was to develop and validate a prediction algorithm for first onset of major depression in the general population. Longitudinal study design with approximate 3-year follow-up. The study was based on data from a nationally representative sample of the US general population. A total of 28 059 individuals who participated in Waves 1 and 2 of the US National Epidemiologic Survey on Alcohol and Related Conditions and who had not had major depression at Wave 1 were included. The prediction algorithm was developed using logistic regression modelling in 21 813 participants from three census regions. The algorithm was validated in participants from the 4th census region (n=6246). Major depression occurred since Wave 1 of the National Epidemiologic Survey on Alcohol and Related Conditions, assessed by the Alcohol Use Disorder and Associated Disabilities Interview Schedule-diagnostic and statistical manual for mental disorders IV. A prediction algorithm containing 17 unique risk factors was developed. The algorithm had good discriminative power (C statistics=0.7538, 95% CI 0.7378 to 0.7699) and excellent calibration (F-adjusted test=1.00, p=0.448) with the weighted data. In the validation sample, the algorithm had a C statistic of 0.7259 and excellent calibration (Hosmer-Lemeshow χ(2)=3.41, p=0.906). The developed prediction algorithm has good discrimination and calibration capacity. It can be used by clinicians, mental health policy-makers and service planners and the general public to predict future risk of having major depression. The application of the algorithm may lead to increased personalisation of treatment, better clinical decisions and more optimal mental health service planning.
    Journal of epidemiology and community health 01/2014; · 3.04 Impact Factor
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    ABSTRACT: Objectif Examiner le lien entre l’inactivité physique et les symptômes de l’anxiété d’un échantillon d’hommes et de femmes de la population générale ayant le diabète sucré de type 2. Méthodes Les critères d’admissibilité comprenaient les résidents du Québec, au Canada, âgés de 40 à 75 ans, ayant un diagnostic de diabète de type 2 (≤ 10 ans) et étant insulino-naïfs, qui avaient participé à une précédente enquête par téléphone sur les traitements du diabète. Parmi les 2028 répondants admissibles, 1953 (96,3 %) répondants qui avaient fourni des détails sur les symptômes d’anxiété ont été inclus dans cette analyse. Les participants ont été interviewés et ont fourni des renseignements sur les facteurs cliniques et sociodémographiques liés au diabète. Résultats Un total de 27,3 % des participants ont rapporté être inactifs physiquement. La prévalence des symptômes d’anxiété légère à grave était de 22,9 %. Les personnes qui avaient des symptômes d’anxiété légère et des symptômes d’anxiété modérée à grave étaient respectivement 1,4 fois et 1,7 fois plus susceptibles de rapporter être inactives que les personnes n’ayant pas de symptômes d’anxiété. Les analyses en sous-groupes selon le sexe révélaient que les femmes qui avaient des symptômes d’anxiété légère étaient 1,5 fois plus susceptibles de rapporter être inactives que les femmes qui n’avaient pas de symptômes d’anxiété, tandis que les hommes qui avaient des symptômes d’anxiété modérée à grave étaient 2,5 fois plus susceptibles d’être inactifs que les hommes qui n’avaient pas de symptômes d’anxiété. Conclusions Les symptômes d’anxiété dans la fourchette légère et dans la fourchette modérée à grave représentent une comorbidité clinique pertinente chez les personnes ayant le diabète de type 2, et les hommes pourraient représenter un sous-groupe particulièrement vulnérable. D’autres recherches sont recommandées pour évaluer davantage le lien entre les symptômes d’anxiété et les comportements de santé liés au diabète.
    Canadian Journal of Diabetes 01/2014; · 0.46 Impact Factor
  • European Psychiatry 01/2014; 29:1. · 3.21 Impact Factor
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    ABSTRACT: Self-rated health (SRH) is a single-item measure that is one of the most widely used measures of general health in population health research. Relatively little is known about changes and the trajectories of SRH in people with chronic medical conditions. The aims of the present study were to identify and describe longitudinal trajectories of self-rated health (SRH) status in people with diabetes. A prospective community study was carried out between 2008 and 2011. SRH was assessed at baseline and yearly at follow-ups (n=1288). Analysis was carried out through trajectory modeling. The trajectory groups were subsequently compared at 4 years follow-up with respect to functioning. FOUR DISTINCT TRAJECTORIES OF SRH WERE IDENTIFIED: 1) 72.2% of the participants were assigned to a persistently good SRH trajectory; 2) 10.1% were assigned to a persistently poor SRH trajectory; 3) mean SRH scores changed from good to poor for one group (7.3%); while 4) mean SRH scores changed from poor to medium/good for another group (10.4%). Those with a persistently poor perception of health status were at higher risk for poor functioning at 4 years follow-up than those whose SRH scores decreased from good to poor. SRH is an important predictor for poor functioning in diabetes, but the trajectory of SRH seems to be even more important. Health professionals should pay attention to not only SRH per se, but also changes in SRH over time.
    PLoS ONE 12/2013; 8(12):e83088. · 3.53 Impact Factor
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    ABSTRACT: OBJECTIVE To evaluate the association between recurrent subthreshold depressive episodes and functioning in a prospective community sample of people with type 2 diabetes.RESEARCH DESIGN AND METHODSA prospective community study in Quebec, Canada, was carried out between 2008 and 2013 (n=1064). Five yearly follow-up assessments (telephone interviews) were conducted. Baseline and the first three follow-up assessments were used to identify recurrent subthreshold depressive episodes (PHQ-9). Functioning (WHODAS-II) and health related quality of life (CDC unhealthy days) at four and five years follow up assessment were the outcome measures.RESULTSNearly half of the participants suffered from at least one episode of subthreshold depressive symptoms. After adjusting for potentially confounding factors, the risk of poor functioning/ impaired health related quality was nearly three times higher (RR=2.86) for participants with four subthreshold depressive episodes compared to participants with no/minimal depression. Results suggest a dose-response relationship: the risk of poor functioning/ impaired health related quality increased with the number of recurrent subthreshold depressive episodes even after controlling for potentially confounding variables (significant linear trend, p<0.001).CONCLUSIONS Recurrent subthreshold depressive symptoms might be an important risk factor for poor health outcomes in type 2 diabetes. Early identification, monitoring and treatment of recurrent subthreshold depressive symptoms might improve functioning and quality of life in people with type 2 diabetes.
    Diabetes care 11/2013; · 7.74 Impact Factor
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    ABSTRACT: Background There exists very little evidence to guide clinical management for preventing recurrence of major depression. The objective of this study was to develop and validate a prediction algorithm for recurrence of major depression. Methods Wave 1 and wave 2 longitudinal data from the U.S. National Epidemiological Survey on Alcohol and Related Condition (2001/2002–2003/2004) were used. Participants with a major depressive episode at baseline and who had visited health professionals for depression were included in this analysis (n = 2,711). Mental disorders were assessed based on the DSM-IV criteria. ResultsWith the development data (n = 1,518), a prediction model with 19 unique factors had a C statistics of 0.7504 and excellent calibration (P = .23). The model had a C statistics of 0.7195 in external validation data (n = 1,195) and 0.7365 in combined data. The algorithm calibrated very well in validation data. In the combined data, the 3-year observed and predicted risk of recurrence was 25.40% (95% CI: 23.76%, 27.04%) and 25.34% (95% CI: 24.73%, 25.95%), respectively. The predicted risk in the 1st and 10th decile risk group was 5.68% and 60.21%, respectively. Conclusions The developed prediction model for recurrence of major depression has acceptable discrimination and excellent calibration, and is feasible to be used by physicians. The prognostic model may assist physicians and patients in quantifying the probability of recurrence so that physicians can develop specific treatment plans for those who are at high risk of recurrence, leading to personalized treatment and better use of resources.
    Depression and Anxiety 11/2013; · 4.29 Impact Factor

Publication Stats

2k Citations
566.80 Total Impact Points


  • 2006–2014
    • McGill University
      • Department of Psychiatry
      Montréal, Quebec, Canada
  • 2010–2013
    • Douglas Mental Health University Institute
      Montréal, Quebec, Canada
  • 2007–2013
    • Université de Montréal
      • • Department of Nutrition
      • • Department of Psychology
      Montréal, Quebec, Canada
  • 2012
    • The University of Calgary
      • Department of Psychiatry
      Calgary, Alberta, Canada
    • Rosalind Franklin University of Medicine and Science
      • Psychology
      North Chicago, IL, United States
    • Children's National Medical Center
      Washington, Washington, D.C., United States
  • 2009
    • Justus-Liebig-Universität Gießen
      Gieben, Hesse, Germany
  • 1997–2004
    • Heinrich-Heine-Universität Düsseldorf
      • Klinisches Institut für Psychosomatische Medizin und Psychotherapie
      Düsseldorf, North Rhine-Westphalia, Germany
    • Technische Universität Dortmund
      Dortmund, North Rhine-Westphalia, Germany
  • 1999
    • Martin Luther University of Halle-Wittenberg
      • Clinic for Psychiatry, Psychotherapy and Psychosomatics
      Halle, Saxony-Anhalt, Germany
  • 1994–1997
    • Ruhr-Universität Bochum
      • Abteilung für Medizinische Psychologie und Medizinische Soziologie
      Bochum, North Rhine-Westphalia, Germany