Geoffrey N. Smith

Abnormalities of myelination in schizophrenia detected in vivo with MRI, and post-mortem with analysis of oligodendrocyte proteins.

Schizophrenia unfolds during the late period of brain maturation, while myelination is still continuing. In the present study, we used MRI and T2 relaxation analysis to measure the myelin water fraction in schizophrenia. In schizophrenia (n=30) compared with healthy subjects (n=27), overall white matter showed 12% lower myelin water fraction (P=0.031), with the most prominent effects on the left genu of the corpus callosum (36% lower, P=0.002). The left anterior genu was affected in both first-episode (P=0.035) and chronic patients (P=0.011). In healthy subjects, myelin water fraction in total white matter and in frontal white matter increased with age, and with years of education, indicating ongoing maturation. In patients with schizophrenia, neither relation was statistically significant. Post-mortem studies of anterior frontal cortex demonstrated less immunoreactivity of two oligodendrocyte-associated proteins in schizophrenia (2′,3′-cyclic nucleotide 3′-phosphodiesterase by 33%, P=0.05; myelin-associated glycoprotein by 27%, P=0.14). Impaired myelination in schizophrenia could contribute to abnormalities of neural connectivity and persistent functional impairment in the illness.

Reduced anterior internal capsule and thalamic volumes in first-episode psychosis.

BACKGROUND The thalamus is the gateway for sensory and motor information en route to the cortex. Information is processed via thalamocortical and corticothalamic pathways coursing through the internal capsules. In this study, we investigated the relationship between the anterior limb of the internal capsule, posterior limb of the internal capsule, and thalamus in first-episode psychosis (FEP). METHODS Twenty-nine FEP subjects (26 DSM-IV schizophrenia, 2 schizoaffective disorder, 1 psychosis not otherwise specified) and 22 healthy volunteers participated in this study. Anterior limb of the internal capsule (AIC), posterior limb of the internal capsule (PIC), and the thalamus volumes were manually determined from MRI scans. RESULTS FEP subjects had reduced AIC volumes (F(1,45)=6.18, p=0.017) and thalamic volumes (F(1,45)=8.00, p=0.007) compared to healthy volunteers. PIC volumes did not differ. Significant correlations between AIC volumes and thalamic volumes were observed in subjects with FEP, but not in healthy volunteers. Negative relationships between thalamic volumes and symptom severity were also observed. CONCLUSIONS The AIC and thalamic volumes were reduced in subjects with FEP compared to healthy volunteers. Abnormalities in thalamocortical and orticothalamic pathways may contribute to functional disruption of neural circuits in psychosis.

The genomic era and perceptions of psychotic disorders : Genetic risk estimation, associations with reproductive decisions and views about predictive testing

As a result of publicity surrounding genetic advances, increasing public awareness of a genetic role in major mental illness may be contributing to a “geneticization” of these illnesses. Geneticization could lead to oversimplified ideas about genetic risk, producing significant social consequences. We sought to investigate perceptions of genetic risk, associated effects on reproductive decisions and attitudes towards genetic testing amongst unaffected relatives of individuals with psychosis. A web‐based survey design was used, which all visitors to a psychosis support/information website had the option to complete. Responders were representative of website visitors, and the study design facilitated collection of a large dataset, although the response rate was low. Over‐estimating risk was associated with reproductive decisions favoring fewer children, and more positive attitudes towards genetic testing. Facilitating accurate risk perception through genetic counseling could significantly impact reproductive decisions, and the appropriate use of genetic tests in the future.

Developmental abnormalities of the hippocampus in First-Episode schizophrenia

BACKGROUND The human hippocampus becomes visible during the first trimester and folds to form the hippocampal fissure (HF) in the second trimester. The walls of this fissure fuse by 30 weeks, although small residual cavities can occur if development is disrupted. The primary purpose of this study was to determine if hippocampal fissures are evident in schizophrenia. A second goal was to assess the association between HF size and premorbid and clinical features of the illness. METHODS Magnetic resonance imaging scans were obtained on 33 patients with first-episode schizophrenia and 19 healthy volunteers. Hippocampal fissures were measured using semi-automated procedures, and hippocampi were manually traced. Birth history and premorbid functioning were assessed using maternal report. RESULTS Patients had a significantly larger mean HF volume and a nonsignificantly smaller hippocampal volume. Hippocampal fissure size was significantly associated with poor educational achievement and with anxiety-depression symptoms during the onset of illness. Smaller hippocampal size was associated with poor premorbid adjustment. CONCLUSIONS Larger HF size and an association between low educational achievement and enlarged HFs suggest abnormal neurodevelopment in schizophrenia. The association between HF size and anxiety-depression symptoms suggests that hippocampal abnormalities underlying HF dilatation may be a predisposing factor for increased stress sensitivity.

Temporal lobe abnormalities in multigenerational families with schizophrenia

Brain structure in familial schizophrenia was studied with computerized tomography in 42 individuals from six multigenerational families. Sulcal enlargement in the lateral temporal cortex, and ventricular and cisternal enlargement in the medial temporal region were observed in psychotic individuals compared to unaffected family members. Genetic factors in familial schizophrenia may exert part of their effect through determining or altering temporal lobe structure.

Violence in treatment resistant psychotic inpatients

This study sought to: a) ascertain the effect on rates of violence by varying its operational definition and b) compare characteristics of violent and nonviolent patients. Aggressive behavior was recorded daily for every patient (N = 78) during a 2-year period. Standardized rating scales were used to rate psychopathology and functioning. Almost two thirds of patients were aggressive to others, and 26% violently assaulted another person. Official incident reports underestimated rates of violence to others, self- harm, and property damage. Multivariate predictive models that greatly improved accuracy over base rates showed that violent patients tended to be female, schizophrenic (nonparanoid type), and abusive of alcohol before admission. Violence is more common in treatment resistant psychotic inpatients than suggested by incident reports. Standardized definitions of violence are urged in order to accurately study its prevalence and correlates. Models combining both historical/demographic and clinical data may enhance prediction of violence.

The assessment of symptom severity and functional impairment with DSM-IV axis V.

OBJECTIVE The Global Assessment of Functioning scale (GAF) is included as axis V in the DSM-IV multiaxial diagnostic system. The GAF is simple to administer and routinely used in treatment planning and as a measure of program performance. The GAF assesses both symptom severity and functional impairment, but the resultant rating provides no information about the contribution of each of these domains. This study aimed to improve the clinical utility of the GAF by creating subscales. METHODS The authors divided the scale into its two principal domains: descriptors of social and occupational functioning (SOFAS) and descriptors of symptoms (GAF minus SOFAS descriptors). These and other measures of symptoms and functioning were used to assess 407 patients while acutely psychotic and again after treatment. RESULTS Symptom scores were of greater severity than functional impairment scores in most cases. Because of this, the GAF score tended to reflect symptom severity rather than functional impairment. The symptom rating was more strongly correlated with measures of positive symptoms, and the functional rating had higher associations with negative symptoms and functional impairment. Both scales were good indicators of clinical change. CONCLUSIONS Findings indicate that GAF ratings for patients with psychosis tend to reflect symptom severity rather than functional impairment. Splitting the GAF into two parts resulted in greater discrimination for this patient group yet retained ease of administration.

The incidence of schizophrenia in European immigrants to Canada

OBJECTIVE The risk for schizophrenia in immigrants to Europe is approximately three times that of native-born populations. Discrimination and marginalization may influence the risk for schizophrenia within migrant populations. The primary objective of the present study was to determine whether the risk associated with migration was also evident 100 years ago. A second objective was to determine whether changing social stresses are associated with changes to the incidence of schizophrenia. METHOD During the first two decades of the twentieth century, the Provincial Mental Hospital was the sole provider of psychiatric services in British Columbia, Canada. Detailed clinical records have been preserved for 99.5% of 2477 patients who had a psychiatric admission between 1902 and 1913. Diagnoses were made after a detailed file review and 807 patients met DSM-IV criteria for first-episode schizophrenia, schizophreniform disorder, schizoaffective disorder, or psychosis not otherwise specified. Diagnoses had high inter-rater reliability. The incidence of schizophrenia in migrants from Britain or Continental Europe was compared with that in the Canadian-born population using indirect standardization and Poisson models. RESULTS Migration from Britain or Continental Europe to Canada in the early twentieth century was associated with an increased rate of schizophrenia; IRR=1.54, (95% CI=1.33-1.78). Incidence increased over time in immigrants but not in the native-born population and this increase occurred during a period of economic recession. CONCLUSIONS Migration was a risk factor for schizophrenia a century ago as it is today. This risk occurred in white migrants from Europe and increased during a period of increased social stress.

The Hotel Study: Multimorbidity in a Community Sample Living in Marginal Housing

OBJECTIVE The health of people living in marginal housing is not well characterized, particularly from the perspective of multimorbid illness. The authors investigated this population in a community sample. METHOD A prospective community sample (N=293) of adults living in single-room occupancy hotels was followed for a median of 23.7 months. Assessment included psychiatric and neurological evaluation, multimodal MRI, and viral testing. RESULTS Previous homelessness was described in 66.6% of participants. Fifteen deaths occurred during 552 person-years of follow-up. The standardized mortality ratio was 4.83 (95% CI=2.91-8.01). Substance dependence was ubiquitous (95.2%), with 61.7% injection drug use. Psychosis was the most common mental illness (47.4%). A neurological disorder was present in 45.8% of participants, with definite MRI findings in 28.0%. HIV serology was positive in 18.4% of participants, and hepatitis C virus serology in 70.3%. The median number of multimorbid illnesses (from a list of 12) was three. Burden of multimorbidity was significantly correlated with lower role functioning score. Comorbid addiction or physical illness significantly decreased the likelihood of treatment for psychosis but not the likelihood of treatment for opioid dependence or HIV disease. Participants who died during follow-up appeared to have profiles of multimorbidity similar to those of the overall sample. CONCLUSIONS This marginally housed cohort had greater than expected mortality and high levels of multimorbidity with adverse associations with role function and likelihood of treatment for psychosis. These findings may guide the development of effective health care delivery in the setting of marginal housing.

A longitudinal study on the effects of typical versus atypical antipsychotic drugs on hippocampal volume in schizophrenia

BACKGROUND Previous studies have reported that hippocampal volumes correlate with symptom severity in schizophrenia. This longitudinal study measured changes in symptoms and hippocampal volume in patients switched from typical antipsychotics to olanzapine. METHODS MRI scans were acquired from patients with chronic schizophrenia (n=10) and healthy volunteers (n=20). At baseline, patients were treated with typical antipsychotics for at least one year, then switched to olanzapine, and rescanned approximately one year later. RESULTS Olanzapine treatment resulted in no significant change in right or left hippocampal volume. Individual changes in right hippocampal volume correlated significantly with changes in symptoms. CONCLUSIONS Hippocampal volume change may serve as a marker of symptom change in patients on olanzapine.