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Dive into the research topics where G.W. MacEwan is active.

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Featured researches published by G.W. MacEwan.


Psychological Medicine | 1998

Obstetric complications, treatment response and brain morphology in adult-onset and early-onset males with schizophrenia.

Geoffrey N. Smith; Lili C. Kopala; Lapointe Js; G.W. MacEwan; Altman S; Flynn Sw; Schneider T; Falkai P; William G. Honer

Background. Substantial variability in age at onset of illness and course of illness exists between patients with schizophrenia. Recent studies suggest that age at illness onset may be useful in defining biologically and clinically distinct subgroups of patients. Methods. Two hundred and ten males with schizophrenia were classified as early-onset or adult-onset according to their age at first hospitalization. Birth history, clinical functioning and treatment response was assessed in a subgroup of patients. Brain anatomy was assessed from CT scans in all patients and in 32 non-psychiatric control subjects. Results. Patients with an early-onset were likely to have a history of obstetric complications, a poor response to neuroleptic treatment, and showed no relationship between ventricle size and duration of illness. Adult-onset patients were less likely to have obstetric complications, more likely to respond to treatment in the first years of illness, and showed an association between brain structure and duration of illness. Conclusions. The distinction between early- and adult-onset patients may have important aetiological and treatment implications.


Schizophrenia Research | 2012

White matter tract abnormalities in first-episode psychosis

D.Y. Lee; Geoffrey N. Smith; Wayne Su; William G. Honer; G.W. MacEwan; J.S. Lapointe; A.T. Vertinsky; Fidel Vila-Rodriguez; Lili C. Kopala; Donna J. Lang

Fibers connecting fronto-temporal and fronto-medial structures that pass through the anterior limb of the internal capsule (ALIC) subserve executive and psychomotor functioning. Both of these functions are adversely affected in schizophrenia, and may be abnormal at illness onset. In a study of first-episode psychosis, we used diffusion tensor imaging (DTI) and cognitive testing to examine ALIC integrity. Fourteen early psychosis patients and 29 healthy volunteers were included. Symptoms were assessed with the Positive and Negative Syndromes Scale (PANSS). All structural and diffusion scans were acquired on a GE Signa 1.5T scanner. A T1-weighted 3D FSPGR Inversion Recovery imaging series was acquired for manual seeding in structural space. Diffusion tensor imaging (DTI) was performed, and all DTI images were co-registered to structural space. Seeds were manually drawn bilaterally on the coronal plane at a specified location. Diffusion images were post-processed for subsequent Tract-based Spatial Statistics (TBSS) analysis. First-episode psychosis patients had significantly smaller fronto-medial and fronto-temporal AIC tract volumes compared to healthy volunteers on the left and the right (p-values<0.04). No differences in mean fractional anisotropy (FA) were seen within either left or right tracts (p-values>0.05), nor did TBSS reveal any other differences in FA values between groups in other regions. Relationships between tract volumes and symptom severity were not observed in this study.


Schizophrenia Research | 1998

Obstetric complications, treatment response and brain morphology in adult onset and early onset females with schizophrenia

Geoffrey N. Smith; S. Dhillon; Lili C. Kopala; S.W. Flynn; Jocelyne S. Lapointe; G.W. MacEwan; S. Altman; T. Schneider; Peter Falkai; William G. Honer

BACKGROUND Substantial variability in age at onset of illness and course of illness exists between patients with schizophrenia. Recent studies suggest that age at illness onset may be useful in defining biologically and clinically distinct subgroups of patients. METHODS Two hundred and ten males with schizophrenia were classified as early-onset or adult-onset according to their age at first hospitalization. Birth history, clinical functioning and treatment response was assessed in a subgroup of patients. Brain anatomy was assessed from CT scans in all patients and in 32 non-psychiatric control subjects. RESULTS Patients with an early-onset were likely to have a history of obstetric complications, a poor response to neuroleptic treatment, and showed no relationship between ventricle size and duration of illness. Adult-onset patients were less likely to have obstetric complications, more likely to respond to treatment in the first years of illness, and showed an association between brain structure and duration of illness. CONCLUSIONS The distinction between early- and adult-onset patients may have important aetiological and treatment implications.


Psychological Medicine | 2015

Cortical morphology and early adverse birth events in men with first-episode psychosis

Geoffrey N. Smith; Allen E. Thornton; Donna J. Lang; G.W. MacEwan; Lili C. Kopala; Wayne Su; William G. Honer


Schizophrenia Research | 1993

Physical anomalies in schizophrenia

C.A.H. Jones; A.S. Bassett; B.D. McGillivray; R. Weksberg; R. Roy; G.W. MacEwan; Geoffrey N. Smith; M. Lang; W.G. Homer


Schizophrenia Research | 1998

A comparison of treatment response between early- and adult-onset schizophrenia

William G. Honer; Lili C. Kopala; Geoffrey N. Smith; S.W. Flynn; Diane H. Fredrikson; K.P. Good; S. Altman; G.W. MacEwan


Schizophrenia Research | 1998

Low birth weight in schizophrenia: Incidence and clinical implications

Geoffrey N. Smith; Natalia Mccarthy; Barbara Meistrich; Lili C. Kopala; S.W. Flynn; Jocelyne S. Lapointe; G.W. MacEwan; S. Altman; William G. Honer


Schizophrenia Research | 1996

The computerised tomography rating scale for schizophrenia (CTRSS): Validity and reliability

S.W. Flynn; Peter Falkai; S. Altman; G.W. MacEwan; Lili C. Kopala; Geoffrey N. Smith; Tom Ehmann; William G. Honer


Schizophrenia Research | 2010

RESOURCE UTILIZATION COSTS IN PSYCHOTIC PATIENTS: THE CANADIAN OSCAR STUDY

Lili C. Kopala; Geoffrey N. Smith; Richard Williams; G.W. MacEwan; A. McIntyre; I. Kowalchuck; N. Schnurr; R. Balshaw; N. Lesnikova; William G. Honer


Schizophrenia Research | 2006

0460 ABNORMALITIES OF SUBREGIONAL MYELINATION IN FIRST-EPISODE PSYCHOSIS PATIENTS USING MYELIN WATER IMAGING

Donna J. Lang; Alex L. MacKay; C. Laule; Lili C. Kopala; G.W. MacEwan; William G. Honer

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William G. Honer

University of British Columbia

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Geoffrey N. Smith

University of British Columbia

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Lili C. Kopala

University of British Columbia

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Jocelyne S. Lapointe

University of British Columbia

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M. Lang

University of British Columbia

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Donna J. Lang

University of British Columbia

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Andra M. Smith

University of British Columbia

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Diane H. Fredrikson

University of British Columbia

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