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Dive into the research topics where Olga Leonova is active.

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Featured researches published by Olga Leonova.


BMJ Open | 2015

Mortality from treatable illnesses in marginally housed adults: a prospective cohort study

Andrea A. Jones; Fidel Vila-Rodriguez; Olga Leonova; Verena Langheimer; Donna J. Lang; Alasdair M. Barr; Ric M. Procyshyn; Geoffrey N. Smith; Krista Schultz; Tari Buchanan; Michael Krausz; Julio S. G. Montaner; G. William MacEwan; Alexander Rauscher; William J. Panenka; Allen E. Thornton; William G. Honer

Objectives Socially disadvantaged people experience greater risk for illnesses that may contribute to premature death. This study aimed to evaluate the impact of treatable illnesses on mortality among adults living in precarious housing. Design A prospective cohort based in a community sample. Setting A socially disadvantaged neighbourhood in Vancouver, Canada. Participants Adults (N=371) living in single room occupancy hotels or recruited from the Downtown Community Court and followed for median 3.8 years. Main outcome measures Participants were assessed for physical and mental illnesses for which treatment is currently available. We compared cohort mortality rates with 2009 Canadian rates. Left-truncated Cox proportional hazards modelling with age as the time scale was used to assess risk factors for earlier mortality. Results During 1269 person-years of observation, 31/371 (8%) of participants died. Compared with age-matched and sex-matched Canadians, the standardised mortality ratio was 8.29 (95% CI 5.83 to 11.79). Compared with those that had cleared the virus, active hepatitis C infection was a significant predictor for hepatic fibrosis adjusting for alcohol dependence and age (OR=2.96, CI 1.37 to 7.08). Among participants <55 years of age, psychosis (HR=8.12, CI 1.55 to 42.47) and hepatic fibrosis (HR=13.01, CI 3.56 to 47.57) were associated with earlier mortality. Treatment rates for these illnesses were low (psychosis: 32%, hepatitis C virus: 0%) compared with other common disorders (HIV: 57%, opioid dependence: 61%) in this population. Conclusions Hepatic fibrosis and psychosis are associated with increased mortality in people living in marginal conditions. Timely diagnosis and intervention could reduce the high mortality in marginalised inner city populations.


PLOS ONE | 2013

Personalized Risk Assessment of Drug-Related Harm Is Associated with Health Outcomes

Andrea A. Jones; Fidel Vila-Rodriguez; William J. Panenka; Olga Leonova; Verena Strehlau; Donna J. Lang; Allen E. Thornton; Hubert Wong; Alasdair M. Barr; Ric M. Procyshyn; Geoffrey N. Smith; Tari Buchanan; Mel Krajden; Michael Krausz; Julio S. G. Montaner; G. William MacEwan; David J. Nutt; William G. Honer

Background The Independent Scientific Committee on Drugs (ISCD) assigned quantitative scores for harm to 20 drugs. We hypothesized that a personalized, ISCD-based Composite Harm Score (CHS) would be associated with poor health outcomes in polysubstance users. Methods A prospective community sample (n=293) of adults living in marginal housing was assessed for substance use. The CHS was calculated based on the ISCD index, and the personal substance use characteristics over four weeks. Regression models estimated the association between CHS and physical, psychological, and social health outcomes. Results Polysubstance use was pervasive (95.8%), as was multimorbid illness (median 3, possible range 0–12). The median CHS was 2845 (interquartile range 1865–3977). Adjusting for age and sex, every 1000-unit CHS increase was associated with greater mortality (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.07–2.01, p = 0.02), and persistent hepatitis C infection (OR 1.29, 95% CI 1.02–1.67, p = 0.04). The likelihood of substance-induced psychosis increased 1.39-fold (95% CI 1.13–1.67, p = 0.001). The amount spent on drugs increased 1.51-fold (1.40–1.62, p < 0.001) and the odds of having committed a crime increased 1.74-fold (1.46–2.10, p < 0.001). Multimorbid illness increased 1.43-fold (95% CI 1.26–1.63, p < 0.001). Conclusions Greater CHS predicts poorer physical, psychological, and social health, and may be a useful quantitative, personalized measure of risk for drug-related harm.


Addiction Biology | 2017

Characterization of white matter integrity deficits in cocaine-dependent individuals with substance-induced psychosis compared with non-psychotic cocaine users

Taylor Willi; Alasdair M. Barr; Kristina Gicas; Donna J. Lang; Fidel Vila-Rodriguez; Wayne Su; Allen E. Thornton; Olga Leonova; Chantelle J. Giesbrecht; Ric M. Procyshyn; Alexander Rauscher; William MacEwan; William G. Honer; William J. Panenka

With sufficient drug exposure, some individuals develop transient psychotic symptoms referred to as ‘substance‐induced psychosis’ (SIP), which closely resemble the symptoms observed in schizophrenia spectrum disorders. The comparability in psychotic presentation between SIP and the schizophrenias suggests that similar underlying neural deficits may contribute to the emergence of psychosis across these disorders. Only a small number of studies have investigated structural alterations in SIP, and all have been limited to volumetric imaging methods, with none controlling for the effects of chronic drug exposure. To investigate white matter abnormalities associated with SIP, diffusion tensor imaging was employed in a group of individuals with cocaine‐associated psychosis (CAP; n = 24) and a cocaine‐dependent non‐psychotic (CDN) group (n = 43). Tract‐based spatial statistics was used to investigate group differences in white matter diffusion parameters. The CAP group showed significantly lower fractional anisotropy values than the CDN group (p < 0.05) in voxels within white matter tracts of fronto‐temporal, fronto‐thalamic and interhemispheric pathways. The greatest differences in white matter integrity were present in the corpus callosum, corona radiata, bilateral superior longitudinal fasciculi and bilateral inferior longitudinal fasciculi. Additionally, the CAP group had voxels of significantly higher radial diffusivity in a subset of the previously mentioned pathways. These results are the first description of white matter integrity abnormalities in a SIP sample and indicate that differences in these pathways may be a shared factor in the expression of different forms of psychosis.


Psychiatry Research-neuroimaging | 2016

Factors affecting severity of positive and negative symptoms of psychosis in a polysubstance using population with psychostimulant dependence.

Taylor Willi; William G. Honer; Allen E. Thornton; Kristina Gicas; Ric M. Procyshyn; Fidel Vila-Rodriguez; William J. Panenka; Ana Aleksic; Olga Leonova; Andrea A. Jones; G. William MacEwan; Alasdair M. Barr

Approximately half of psychostimulant users experience psychotic symptoms, which include both positive and negative symptoms. Prior reports have exclusively used positive symptoms to characterize psychostimulant associated psychosis. Symptoms vary dramatically in severity, though most investigations categorize psychosis as a dichotomous occurrence. To explore the association between different substances of abuse and the severity of psychotic symptoms, we investigated 171 individuals meeting DSM-IV-TR criteria for psychostimulant (cocaine or methamphetamine) dependence in an observational cross-sectional study. Participants were predominantly male (72.5%), recruited from a socially disadvantaged neighborhood in Vancouver, Canada, with a mean age of 45.5(±8.8) years. Of the total sample, 85% were dependent on cocaine, and 28.1% were dependent on methamphetamine. Participants had a median total PANSS score of 63, ranging from 37 to 111. Demographic information, current substance use and early substance exposure were used to predict positive and negative psychotic symptom severity in linear regression models. Increased severity of positive psychotic symptoms was significantly related to greater methamphetamine and marijuana use in the past 28 days, and methadone-abstinence. Negative symptom severity was related to increased opioid use in the past 28 days. There was no overlap between predictors of positive and negative symptom severity.


The Canadian Journal of Psychiatry | 2017

The Hotel Study—Clinical and Health Service Effectiveness in a Cohort of Homeless or Marginally Housed Persons:

William G. Honer; Alejandro Cervantes-Larios; Andrea A. Jones; Fidel Vila-Rodriguez; Julio S. G. Montaner; Howard Tran; Jimmy Nham; William J. Panenka; Donna J. Lang; Allen E. Thornton; Talia Vertinsky; Alasdair M. Barr; Ric M. Procyshyn; Geoffrey N. Smith; Tari Buchanan; Mel Krajden; Michael Krausz; G. William MacEwan; Kristina Gicas; Olga Leonova; Verena Langheimer; Alexander Rauscher; Krista Schultz

Objective: The Hotel Study was initiated in Vancouver’s Downtown East Side (DTES) neighborhood to investigate multimorbidity in homeless or marginally housed people. We evaluated the clinical effectiveness of existing, illness-specific treatment strategies and assessed the effectiveness of health care delivery for multimorbid illnesses. Method: For context, we mapped the housing locations of patients presenting for 552,062 visits to the catchment hospital emergency department (2005-2013). Aggregate data on 22,519 apprehensions of mentally ill people were provided by the Vancouver Police Department (2009-2015). The primary strategy was a longitudinal cohort study of 375 people living in the DTES (2008-2015). We analysed mortality and evaluated the clinical and health service delivery effectiveness for infection with human immunodeficiency virus or hepatitis C virus, opioid dependence, and psychosis. Results: Mapping confirmed the association between poverty and greater number of emergency visits related to substance use and mental illness. The annual change in police apprehensions did not differ between the DTES and other policing districts. During 1581 person-years of cohort observation, the standardized mortality ratio was 8.43 (95% confidence interval, 6.19 to 11.50). Physician visits were common (84.3% of participants over 6 months). Clinical treatment effectiveness was highest for HIV/AIDS, intermediate for opioid dependence, and lowest for psychosis. Health service delivery mechanisms provided examples of poor access, poor treatment adherence, and little effect on multimorbid illnesses. Conclusions: Clinical effectiveness was variable, and illness-specific service delivery appeared to have little effect on multimorbidity. New models of care may need to be implemented.


Neuropsychology (journal) | 2017

Structural brain markers are differentially associated with neurocognitive profiles in socially marginalized people with multimorbid illness

Kristina Gicas; Chantelle J. Giesbrecht; William J. Panenka; Donna J. Lang; Geoffrey N. Smith; Fidel Vila-Rodriguez; Olga Leonova; Andrea A. Jones; Alasdair M. Barr; Ric M. Procyshyn; Tari Buchanan; G. William MacEwan; Wayne Su; A. Talia Vertinsky; Alexander Rauscher; William G. Honer; Allen E. Thornton

Objective: The authors examined associations between complementary fronto-temporal structural brain measures (gyrification, cortical thickness) and neurocognitive profiles in a multimorbid, socially marginalized sample. Method: Participants were recruited from single-room occupancy hotels and a downtown community courthouse (N = 299) and grouped on multiple neurocognitive domains using cluster analysis. Subsequently, the authors evaluated whether the fronto-temporal brain indices, and proxy measures of neurodevelopment and acquired brain insult/risk exposure differentiated members of the 3 distinct neurocognitive clusters. Results: Greater frontal and temporal gyrification and more proxies of aberrant neurodevelopment were associated with the lowest functioning neurocognitive cluster (Cluster 3). Further, for older participants (50+ years), increased cortical thickness in frontal regions was associated with the higher functioning neurocognitive cluster (Cluster 1). Finally, the greatest acquired brain insult/risk exposure was associated with the cluster characterized by selective decision-making impairment (Cluster 2). Conclusions: Fronto-temporal structural brain indices, and proxies of neurodevelopment and acquired brain insult/risk exposure were differentially associated with neurocognitive profiles in socially marginalized persons. These findings highlight the unique pathways to neurocognitive impairment in a heterogeneous population and help to clarify the vulnerabilities confronted by different subgroups.


PLOS ONE | 2016

The Positive and Negative Syndrome Scale (PANSS): A Three-Factor Model of Psychopathology in Marginally Housed Persons with Substance Dependence and Psychiatric Illness

Chantelle J. Giesbrecht; Norm O’Rourke; Olga Leonova; Verena Strehlau; Karine Paquet; Fidel Vila-Rodriguez; William J. Panenka; G. William MacEwan; Geoffrey N. Smith; Allen E. Thornton; William G. Honer

Rates of psychopathology are elevated in marginalized and unstably housed persons, underscoring the need for applicable clinical measures for these populations. The Positive and Negative Syndrome Scale (PANSS) is a clinical instrument principally developed for use in schizophrenia to identify the presence and severity of psychopathology symptoms. The current study investigates whether a reliable and valid PANSS factor structure emerges in a marginally housed, heterogeneous sample recruited from the Downtown Eastside of Vancouver where substance use disorders and psychiatric illness are pervasive. Participants (n = 270) underwent structured clinical assessments including the PANSS and then were randomly assigned to either exploratory (EFA) or confirmatory factor analytic (CFA) subsamples. EFA pointed to a novel three factor PANSS. This solution was supported by CFA. All retained items (28 out of 30) load significantly upon hypothesized factors and model goodness of fit analyses are in the acceptable to good range. Each of the three first-order factor constructs, labeled Psychosis/Disorganized, Negative Symptoms/Hostility, and Insight/Awareness, contributed significantly to measurement of a higher-order psychopathology construct. Further, the latent structure of this 3-factor solution appears temporally consistent over one-year. This PANSS factor structure appears valid and reliable for use in persons with multimorbidity, including substance use disorders. The structure is somewhat distinct from existing solutions likely due to the unique characteristics of this marginally housed sample.


Schizophrenia Research | 2018

Hippocampal volume and vasculature before and after exercise in treatment-resistant schizophrenia

Melissa Woodward; Kristina Gicas; Darren E.R. Warburton; Randall F. White; Alexander Rauscher; Olga Leonova; Wayne Su; Geoffrey N. Smith; A.E. Thornton; A.T. Vertinsky; Aaron A. Phillips; Vina M. Goghari; William G. Honer; Donna J. Lang

BACKGROUND Schizophrenia is associated with poor cognitive function and elevated cardiometabolic disease risk. These health concerns may exacerbate neurocognitive dysfunction associated with hippocampal abnormalities, particularly hippocampal volume reductions. Regular exercise is thought to improve symptom severity, reduce depression, and improve cognition in schizophrenia, and may trigger exercise-mediated hippocampal growth. The potential for the benefits of exercise for treatment-resistant schizophrenia patients has not been clearly assessed. This study aims to assess the effect of exercise on hippocampal plasticity and clinical outcomes in chronic schizophrenia. METHODS Seventeen DSM-IV criteria schizophrenia or schizoaffective disorder patients completed a customized moderate intensity 12-week aerobic or weight-bearing exercise program. Adherence rates were 83% ± 9.4%) with 70% of participants completing the entire exercise program. Concomitant neuroimaging, clinical and cognitive assessments were obtained at baseline and 12-weeks. RESULTS At follow-up, symptom severity scores (t(16) = -16.8, p. ≤ 0.0001) and social functioning (t(16) = 4.4, p. = 0.0004) improved. A trend for improved depression scores (t(16) = -2.0, p. = 0.06) with no change in anxiety, or extrapyramidal symptoms were seen. Hippocampal volume increased (t(16) = -2.54, p. = 0.02), specifically in the left CA-1 field (F(16) = -2.33, p. = 0.03). Hippocampal vascular volume was unchanged. Change in hippocampal volume and vascular volume was not significantly correlated with change in symptom severity or affect scores. CONCLUSIONS Adjunct exercise may accelerate symptom improvement in treatment-resistant psychosis patients. While the underlying mechanism remains unclear, these results indicate that chronic schizophrenia patients experience hippocampal plasticity in response to exercise. STUDY REGISTRATION Clinical Trials.govNCT01392885.


Schizophrenia Research | 2016

Subcortical grey matter alterations in cocaine dependent individuals with substance-induced psychosis compared to non-psychotic cocaine users

Taylor Willi; Donna J. Lang; William G. Honer; Geoff Smith; Allen E. Thornton; William J. Panenka; Ric M. Procyshyn; Fidel Vila-Rodriguez; Wayne Su; A. Talia Vertinsky; Olga Leonova; Alexander Rauscher; G. William MacEwan; Alasdair M. Barr


Canadian Journal of Public Health-revue Canadienne De Sante Publique | 2018

Clinical and functional characteristics of young adults living in single room occupancy housing: preliminary findings from a 10-year longitudinal study

Skye Barbic; Andrea A. Jones; Melissa Woodward; Matt Piercy; Steve Mathias; Fidel Vila-Rodriguez; Olga Leonova; Geoffrey N. Smith; Tari Buchanan; Alexandra T. Vertinsky; Stephanie Gillingham; William J. Panenka; Alexander Rauscher; Alasdair M. Barr; Ric M. Procyshyn; G. William MacEwan; Donna J. Lang; Allen E. Thornton; Manraj K. Heran; Adelena M. Leon; Michael Krausz; William G. Honer

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William G. Honer

University of British Columbia

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Donna J. Lang

University of British Columbia

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Fidel Vila-Rodriguez

University of British Columbia

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Ric M. Procyshyn

University of British Columbia

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William J. Panenka

University of British Columbia

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Alasdair M. Barr

University of British Columbia

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Alexander Rauscher

University of British Columbia

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Andrea A. Jones

University of British Columbia

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G. William MacEwan

University of British Columbia

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