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Featured researches published by Jatinder Takhar.


Schizophrenia Research | 2002

One year outcome in first episode psychosis: influence of DUP and other predictors

Ashok Malla; Ross Norman; Rahul Manchanda; M.Rashid Ahmed; Derek Scholten; Raj Harricharan; Leonard Cortese; Jatinder Takhar

BACKGROUND A number of studies have reported evidence of a relationship between longer duration of untreated psychosis (DUP) and poorer outcome at 1 year while others have failed to find such evidence. It is possible that several other predictors may confound this relationship and there may be different predictors for different dimensions of outcome. In the current study we examined relationship between DUP and several other predictors, and 1 year outcome on rate and level of remission as well as level of positive, negative, depressive and anxiety symptoms in a community cohort of first episode psychosis patients. METHOD All potential cases of a first episode of non-affective psychosis were assessed and offered treatment in a comprehensive treatment program. Data were collected on all patients who completed 1 year of treatment on a number of predictor variables (DUP, length of the prodromal period, age of onset, gender, pre-morbid adjustment during childhood and adolescence, diagnosis) and outcome variables (level of remission, positive, negative, depression and anxiety symptoms based on ratings on SAPS, SANS, CDS and HAS, respectively). Data were analysed using an analysis of variance, bivariate correlations and hierarchical regression analysis. RESULTS Of a total of 130 patients were offered treatment, 106 completed 1 year of treatment and complete data were available on 88 subjects, 80% of whom met criteria for schizophrenia spectrum psychosis. The rate and level of remission were significantly higher for patients with shorter DUP (<22 weeks). DUP was the only independent predictor of the level of remission as well as reality distortion at 1 year; for disorganization syndrome and negative symptoms it was the age of onset and level of premorbid adjustment in adolescence, respectively; while the level of anxiety was predicted by the length of the prodrome. Additional predictors increased the variance explained by each model. CONCLUSION Our results confirmed the independent role of DUP in remission and positive symptom outcome at 1 year, thus providing support for the enthusiasm for early intervention. However, the model including DUP and premorbid adjustment in early adolescence explained a greater amount of variance in outcome on positive symptoms than DUP alone. On the other hand, outcome on negative symptoms, disorganization and anxiety are more likely to be influenced by longer term characteristics such as premorbid adjustment, earlier age of onset, gender and the length of the prodromal period, and therefore may not be as responsive to effects of early intervention.


Psychological Medicine | 2006

Predictors of rate and time to remission in first-episode psychosis : a two-year outcome study

Ashok Malla; Ross Norman; Norbert Schmitz; Rahul Manchanda; Laura Béchard-Evans; Jatinder Takhar; Raj Haricharan

BACKGROUND The evidence regarding the independent influence of duration of untreated psychosis (DUP) on rate and time to remission is far from unequivocal. The goal of the current study was to examine the role of predictors for rate and time to remission in first-episode psychosis (FEP). METHOD The differential effect of age, gender, age of onset, duration of untreated psychosis (DUP), duration of untreated illness (DUI), pre-morbid adjustment, co-morbid diagnosis of substance abuse and adherence to medication on the rate of and time to remission were estimated using a logistic and Poisson regression, and survival analysis respectively, in FEP patients. RESULTS In a sample of 107 FEP patients 82.2% achieved remission over a period of 2 years after a mean of 10.3 weeks (range 1-72). Regression analysis, based on complete data on all variables of interest (n=80), showed status of remission to be positively influenced by better pre-morbid adjustment (RR 0.57, 95% CI 0.34-0.95, p<0.05), later age of onset (RR 1.09, 95% CI 1.05-1.13, p<0.0001), higher level of adherence to medication (RR 1.96, 95% CI 1.38-2.76, p<0.001) and shorter DUI (RR 0.99, 95% CI 0.997-0.999, p<0.005). Time to remission was influenced by age of onset (HR 1.04, 95% CI 1.00-1.08, p<0.04) and adherence to medication (HR 1.58, 95% CI 1.11-2.23, p<0.01). CONCLUSIONS Improving adherence to medication early in the course of treatment may be an important intervention to improve short-term outcome.


Schizophrenia Research | 2005

A 4.0-T fMRI study of brain connectivity during word fluency in first-episode schizophrenia

Kristine Boksman; Jean Théberge; Peter C. Williamson; Dick J. Drost; Ashok Malla; Maria Densmore; Jatinder Takhar; William Pavlosky; Ravi S. Menon; Richard W. J. Neufeld

OBJECTIVE To use functional magnetic resonance imaging (fMRI) to investigate functional connectivity, and hence, underlying neural networks, in never-treated, first-episode patients with schizophrenia using a word fluency paradigm known to activate prefrontal, anterior cingulate, and thalamic regions. Abnormal connectivity between the prefrontal cortex (PFC) and other brain regions has been demonstrated in chronic, medicated patients in previous positron emission tomography (PET) studies, but has not to our knowledge, previously been demonstrated using both first-episode, drug-naïve patients and fMRI technology. METHODS A 4.0-Tesla (T) fMRI was used to examine activation and functional connectivity [psychophysiological interactions (PPIs)] during a word fluency task compared to silent reading in 10 never-treated, first-episode patients with schizophrenia and 10 healthy volunteers of comparable age, sex, handedness, and parental education. RESULTS Compared to healthy volunteers, the schizophrenia patient group exhibited less activation during the word fluency task, mostly in the right anterior cingulate and prefrontal regions. Psychophysiological interactions between right anterior cingulate and other parts of the brain revealed a localized interaction with the left temporal lobe in healthy volunteers during the task and a widespread unfocussed interaction in patients. CONCLUSION These findings suggest anterior cingulate involvement in the neuronal circuitry underlying schizophrenia.


Schizophrenia Research | 2005

Social support and three-year symptom and admission outcomes for first episode psychosis

Ross Norman; Ashok Malla; Rahul Manchanda; Raj Harricharan; Jatinder Takhar; Sandra Northcott

This paper presents the first published findings examining the relationship of social support to three-year symptom outcome and hospitalizations for a group of first episode patients with psychotic disorders. Social support was measured using items from the provider version of the Wisconsin Quality of Life Scale as assessed at the time of initiation of treatment for 113 patients. Outcome was assessed by level of positive and negative symptoms at three-year follow-up and number of psychiatric admissions during those three years. Higher levels of social support were found to correlate with lower levels of positive symptoms and few hospitalizations at follow-up. The relationship of social support to follow-up symptoms and hospitalization was independent of other potential predictors such as gender, age, premorbid adjustment and duration of untreated illness.


Journal of Nervous and Mental Disease | 2004

Can patients at risk for persistent negative symptoms be identified during their first episode of psychosis

Ashok Malla; Ross Norman; Jatinder Takhar; Rahul Manchanda; Laurel Townsend; Derek Scholten; Raj Haricharan

Patients with schizophrenia who show persistent negative symptoms are an important subgroup, but they are difficult to identify early in the course of illness. The objective of this study was to examine characteristics that discriminate between first-episode psychosis (FEP) patients in whom primary negative symptoms did or did not persist after 1 year of treatment. Patients with a DSM-IV diagnosis of FEP whose primary negative symptoms did (N = 36) or did not (N = 35) persist at 1 year were contrasted on their baseline and 1-year characteristics. Results showed that patients with persistent primary negative symptoms (N = 36) had a significantly longer duration of untreated psychosis (p < .005), worse premorbid adjustment during early (p < .001) and late adolescence (p < .01), and a higher level of affective flattening (p < .01) at initial presentation compared with patients with transitory primary negative symptoms. The former group also showed significantly lower remission rates at 1 year (p < .001). Multiple regression analysis confirmed the independent contribution of duration of untreated psychosis, premorbid adjustment, and affective flattening at baseline to the patients’ likelihood of developing persistent negative symptoms. It may therefore be possible to distinguish a subgroup of FEP patients whose primary negative symptoms are likely to persist on the basis of characteristics shown at initial presentation for treatment.


Acta Psychiatrica Scandinavica | 2002

Negative symptoms in first episode non-affective psychosis

Ashok Malla; Jatinder Takhar; Ross Norman; Rahul Manchanda; Leonard Cortese; Raj Haricharan; Mary Verdi; Rashid Ahmed

Objective: To determine the prevalence of negative symptoms and to examine secondary sources of influence on negative symptoms and the role of specific negative symptoms in delay associated with seeking treatment in first episode non‐affective psychosis.


Schizophrenia Research | 2005

Relationship of neuromotor disturbances to psychosis symptoms in first-episode neuroleptic-naïve schizophrenia patients

Leonardo Cortese; Michael P. Caligiuri; Ashok Malla; Rahul Manchanda; Jatinder Takhar; Raj Haricharan

From the very inception of the modern diagnostic scheme for psychotic disorders, abnormalities in motor function have been observed in these conditions. Despite convergence from multiple areas of research supporting the notion that multiple frontal-subcortical circuits regulate motor and limbic behavior, the precise relationship between motor abnormalities and psychopathology has not been elucidated. The goals of this study were to examine the prevalence of extrapyramidal signs (EPS) in first-episode schizophrenia patients and their relationships to three psychopathological dimensions (positive psychosis syndrome, negative syndrome, and disorganization). We assessed EPS using traditional observer-based as well as quantitative instrumental measures in 39 neuroleptic-naive first-episode schizophrenia subjects. Subjects were followed for 6 months after initiating antipsychotic treatment to examine the stability of motor-limbic relationships. Four main findings emerged from this study. First, depending on the measure used the prevalence of dyskinesia prior to treatment ranged from 13% to 20%. The prevalence of parkinsonism ranged from 18% to 28%. Second, severity of dyskinesia was associated with the positive psychotic syndrome; whereas parkinsonism was associated with the positive psychosis, negative syndrome and disorganization. Third, psychopathology improved significantly across all symptom dimensions following antipsychotic treatment, while EPS remained stable. This suggests that some motor abnormalities in schizophrenia may reflect trait characteristics. Fourth, abnormalities on the pre-treatment instrumental measure of parkinsonism predicted greater improvement on positive psychosis symptoms following treatment (p=0.008). Our findings support the notion that neuromotor disturbances may be a core feature of schizophrenia in a substantial proportion of patients and implicate multiple fronto-striatal circuits regulating limbic and neuromotor behavior in schizophrenia.


Schizophrenia Research | 2007

Does treatment delay predict occupational functioning in first-episode psychosis?

Ross Norman; Ashok K. Mallal; Rahul Manchanda; Deborah Windell; Raj Harricharan; Jatinder Takhar; Sandra Northcott

Although duration of untreated psychosis (DUP) predicts treatment outcome as assessed by symptoms in first-episode psychosis, there is much less evidence concerning its relation to social functioning. We present the results of a prospective study of 163 first-episode psychosis patients examining occupational activity at three years, after initiation of treatment. Both shorter DUP and higher social support were significantly associated with more full time occupational activity at follow-up. The findings suggest the importance of reducing treatment delay and increasing social support in order to improve occupational outcomes for those with first-episode psychosis.


Psychiatry Research-neuroimaging | 2004

A comparison of two novel antipsychotics in first episode non-affective psychosis: one-year outcome on symptoms, motor side effects and cognition.

Ashok Malla; Ross Norman; Derek Scholten; Laurel Townsend; Rahul Manchanda; Jatinder Takhar; Raj Haricharan

The main objective of this study was to compare 1-year outcome on symptoms, extrapyramidal side effects (EPS) , positive and negative symptoms, and domains of cognition in first episode psychosis (FEP) patients. Drug-naive FEP patients, who were similar on a number of characteristics likely to affect outcome, were treated with only one antipsychotic (risperidone or olanzapine) for at least 1 year and compared at baseline and after 1 year of treatment. Differences in outcome were assessed using an analysis of co-variance with change scores between initial assessment and after 1 year of treatment on levels of psychotic, disorganization and psychomotor poverty symptoms, EPS (parkinsonism, akathesia and dyskineisa) and domains of cognition as the dependent variable, respective baseline scores as covariates, and drug group as the independent variable. While patients in both groups showed substantial improvement, there were no significant differences in the magnitude of change in reality distortion, disorganization and psychomotor poverty symptoms. Trends in change in EPS favouring olanzapine and on some domains of cognition (processing speed and executive functions) favouring risperidone failed to reach statistical significance. The failure to confirm previous claims of greater improvement on either risperidone or olanzapine in patients with a first episode of psychosis may be the result of methodological bias introduced by unequal dosing between the two drugs or the use of chronically ill and treatment-refractory patients in previous studies.


Journal of Continuing Education in The Health Professions | 2007

Developing an Instrument to Measure Bias in CME.

Jatinder Takhar; Dave Dixon; Jill Donahue; Bernard Marlow; Craig Campbell; Ivan Silver; Jason Eadie; Celine Monette; Ivan Rohan; Abi Sriharan; Kathryn Raymond; Jennifer J. Macnab

Introduction: The pharmaceutical industry, by funding over 60% of programs in the United States and Canada, plays a major role in continuing medical education (CME), but there are concerns about bias in such CME programs. Bias is difficult to define, and currently no tool is available to measure it. Methods: Representatives from industry and academia collaborated to develop a tool to illuminate and measure bias in CME. The tool involved the rating of 14 statements (1 = strongly disagree, 4 = strongly agree) and was used to evaluate 17 live CME events. Cronbachs alpha was used to assess the internal consistency of the scale. Results: Cronbachs alpha for the total score was 0.82, indicating excellent internal consistency. Incomplete or biased data, data presented in an unbalanced manner, and experience not integrated with evidence‐based medicine were found to correlate strongly with the total score. Use of trade names showed a low correlation with the total, and nondeclaration of conflict of interest correlated negatively with the total. These associations suggest that whereas sponsor companies may declare conflicts of interest, such a declaration may not ensure an unbiased presentation. Discussion: The tool and the data from this study can be used to raise awareness about bias in CME. Policymakers can use this tool to ensure that CME providers meet the standards for education, and CME providers can use the tool for conducting random audits of events they have accredited.

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Rahul Manchanda

University of Western Ontario

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Ross Norman

University of Western Ontario

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Raj Haricharan

London Health Sciences Centre

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Jason Eadie

University of Western Ontario

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Derek Scholten

London Health Sciences Centre

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David Dixon

University of Western Ontario

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Dick J. Drost

University of Western Ontario

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Jean Théberge

Lawson Health Research Institute

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Laurel Townsend

London Health Sciences Centre

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