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Biomedical subjects

M Beiser

Publications and source records attributed to M Beiser.

At least 37 records · Page 2Linked to original sources
PubMed1996

Eye-tracking performance and adaptive functioning over the short-term course of first-episode psychosis.

We examined the relationship of smooth pursuit eye tracking to the course of first-episode psychosis. Various measures of social, occupational, and psychological functioning were obtained for 134 persons with diagnoses of schizophrenia, schizophreniform disorder, or psychotic mood disorder at the time of their psychosis and 9 and 18 months later. Poor eye-tracking performance was associated with generally impaired functioning over the 18-month course of disorder for patients with schizophrenia. A similar association between smooth pursuit and adaptive functioning was not found in patients with schizophreniform or affective disorder. The results suggest that patients with schizophrenia who are characterized by poor eye tracking have a more severe disorder, indications of which are present at the onset of their psychosis.

Adolescent↗
PubMed1996

Visual event-related potentials in first-episode psychotic patients and their relatives.

We conducted a comprehensive examination of the sensory visual event-related potential (ERP) of psychiatric patients and their relatives using a methodology that improves upon those used previously by other investigators. One hundred thirty-five patients at the onset of their first psychotic episode, 146 first-degree relatives of these patients, and 113 normal controls were exposed to light flashes of four different intensities while their ERPs were recorded from three central scalp sites. For most analyses, various ERP amplitude measures did not discriminate the different psychiatric groups or their relatives either from one another or from the normal controls. These findings indicate that patients with schizophrenia, schizophreniform disorder, and affective disorder at the early stage of their illnesses do not display significant deficits in the processing and regulation of simple sensory visual stimulation.

Adolescent↗
PubMed1995

Five-year course of schizophreniform disorder.

Roughly one-quarter of persons experiencing a first episode of psychosis and receiving a diagnosis of schizophreniform disorder recovered within 6 months of the onset of illness. Five years later, these 'true schizophreniform disorder' subjects were functioning better than others who experienced a first episode of schizophrenia or affective disorder. Although 40% of people with schizophrenia or affective disorder were rehospitalized at least once during the 5-year follow-up, none from the true schizophreniform disorder group reentered the hospital. Compared with people with schizophrenia, true schizophreniform disorder subjects had more positive symptoms, fewer negative symptoms, and more manic symptoms. Thus, a schizophrenia-like acute remitting psychosis has sufficiently unique clinical features to merit separate diagnostic classification.

Adolescent↗
PubMed1995

Negative symptoms in the course of first-episode affective psychosis.

To determine whether the prognostic implications of negative symptoms apply to functional psychotic disorders other than schizophrenia, we investigated the significance of negative symptoms in the 18-month course of individuals experiencing a first episode of affective psychosis. Although negative symptoms were found to occur during the acute phase of a major depression or a bipolar disorder with psychotic features, they did not endure and had limited prognostic value. Further, the findings suggest that enduring negative symptoms may be specific to schizophrenia.

Adolescent↗
PubMed1995

Immigrant and refugee children in Canada.

In view of Canada's commitment to immigration, understanding the sources of successful adaptation by immigrant and refugee children is vital. This paper reviews the literature on the mental health of migrant children and suggests an agenda for future research.

Acculturation↗
PubMed1994

Resting EEG in first-episode and chronic schizophrenia.

We examined the frequency characteristics of the electroencephalogram (EEG) in 102 schizophrenic patients (44 first-episode and 58 chronic patients) and 102 normal comparison subjects. EEGs of schizophrenic patients had more delta (1-3 Hz) and theta (3.125-8 Hz) activity and less alpha (8.125-13 Hz) activity than normal comparison subjects. There were no significant differences in the EEG frequency composition of first-episode and chronic patients. Because first-episode and chronic patients were characterized by different disorder durations and treatment histories, the similarity of their EEGs suggests that EEG abnormalities are stable characteristics of schizophrenia and are not treatment-related epiphenomena. A principal components analysis of EEG power bands identified an augmented low frequency-diminished alpha component and a beta component. Schizophrenic patients had significantly higher scores on the augmented low frequency-diminished alpha component than did normal comparison subjects, and there was no significant group difference in scores on the beta component. The findings of this investigation suggest that EEG abnormalities in schizophrenia reflect aspects of brain dysfunction.

Acute Disease↗
PubMed1994

Temporal stability of smooth-pursuit eye tracking in first-episode psychosis.

We evaluated the temporal stability of smooth-pursuit eye tracking in 38 schizophrenic, 42 nonschizophrenic psychotic (bipolar, depressive, paranoid psychotic, and schizophreniform), and 49 normal subjects. Pursuit performance was evaluated on two testing occasions separated by approximately 9.5 months. Retest reliability coefficients of root mean square (RMS) error scores for schizophrenic and normal subjects were .68 and .57, respectively. The reliability coefficients of RMS error scores for the nonschizophrenic psychotic patients ranged from .44 to .51. Level of psychological functioning was not significantly related to tracking performance, and most patients' pursuit performance remained stable despite changes in medication and clinical status. These results support the hypothesis that eye tracking dysfunction is a trait characteristic that can serve as a vulnerability indicator of schizophrenia.

Adult↗
PubMed1994

Resting EEG in first-episode schizophrenia patients, bipolar psychosis patients, and their first-degree relatives.

We evaluated the resting electroencephalogram (EEG) of 50 first-episode schizophrenia patients and 55 of their relatives, 31 first-episode bipolar patients and 35 of their relatives, and 113 nonpsychiatric subjects and 42 of their relatives. The frequency characteristics of the EEG showed moderate stability for a subgroup of these subjects (n = 106) who were tested twice, approximately 9 months apart. Both the schizophrenia and bipolar patients showed a generalized pattern of increased delta and theta and decreased alpha activity. The bipolar patients demonstrated additional right hemisphere activity that was not present among the schizophrenia patients and nonpsychiatric subjects, a finding consistent with hypotheses concerning nondominant hemisphere involvement in the regulation of elated mood. The schizophrenia patients' female relatives and/or relatives with affective disorders and the bipolar patients had significantly reduced peak alpha frequencies. This finding may be related to reduced information processing capacity among these subjects.

Adolescent↗
PubMed1994

Biological and psychosocial predictors of job performance following a first episode of psychosis.

OBJECTIVE: The purposes of this study were 1) to evaluate occupational functioning 18 months after a first episode of psychosis and 2) to determine predictors of differential outcome. METHOD: Using a variety of sociodemographic, clinical, and psychophysiological measures, the project team assessed adults experiencing a first episode of schizophrenia (N = 33) or affective psychosis (N = 31). Identical measures were obtained from a comparison group (N = 46) who had no history of psychiatric disorder. Work performance was rated at entry into the study and 18 months later. RESULTS: At entry into the study, the schizophrenic subjects displayed the worst job performance, the asymptomatic individuals the best. The subjects with affective psychosis fell in between. Each of the two diagnostic groups evidenced postmorbid occupational decline. Three factors predicted good outcome in the schizophrenic group--good premorbid job performance, female gender, and scores on putative markers of biological vulnerability for the illness. For the affective disorder group, positive labeling by a significant other proved the only predictor of good outcome. CONCLUSIONS: These findings suggest that post-morbid occupational decline is common to both schizophrenia and affective psychosis. Past accomplishment and biological vulnerability predicted short-term course for these schizophrenic patients; psychosocial factors played a more prominent role in affective psychosis.

Adolescent↗
PubMed1994

Handedness in first-episode psychotic patients and their first-degree biological relatives.

We evaluated the handedness of 58 schizophrenia patients and 54 of their relatives, 23 patients with major depression with psychosis and 24 of their relatives, 36 patients with bipolar psychosis and 33 of their relatives, and 119 nonpsychiatric subjects and 42 of their relatives. Computerized tomography measures were also available for a subset of the psychotic patients. The schizophrenia patients were significantly more left-handed than any of the other groups, and increased sinistrality was also associated with larger lateral ventricle to brain area ratios. The relatives of the schizophrenia patients did not significantly differ on handedness from either the relatives of the affective psychosis patients or the nonpsychiatric subjects. Our findings do not support the notion that left-handedness in schizophrenia is genetically influenced. More research with larger family member data sets is warranted to further explore this possibility.

Adolescent↗
PubMed1993

Unemployment, underemployment and depressive affect among Southeast Asian refugees.

This study of 1348 adult Southeast Asian refugees resettling in Vancouver, British Columbia and a comparison sample of 319 permanent residents of the city demonstrates a reciprocal relationship between unemployment and depressive affect. Increased risk of depression accompanied job loss and depression made it more difficult to stay employed. Although the association between unemployment and depression was common to both refugee and host society samples, links between these phenomena proved different in the two groups. In contrast to the refugees for whom income loss was the over-riding stress resulting from job loss, loss of esteem and loss of social contact also proved to be salient stressors for resident Canadians. Although a threat to the mental health of resident Canadians, underemployment--working at a level which considering one's education and previous occupation, is lower than might be expected--did not jeopardize the mental health of refugees.

Adult↗
PubMed1993

The association between lithium carbonate and smooth pursuit eye tracking among first-episode patients with psychotic affective disorders.

The association between treatment with lithium carbonate and smooth pursuit eye tracking performance was investigated in first-episode patients with psychotic affective disorders. The horizontal pursuit performance of patients with major depression and bipolar disorder who were receiving lithium carbonate was contrasted with that of patients not receiving lithium carbonate. In addition, the accuracy and quality of pursuit eye tracking was examined in bipolar patients whose lithium status changed from the time of initial testing to the time of retest 10 months later. For the combined group of depressed and bipolar patients, treatment with lithium carbonate was not associated with worse pursuit performance. Bipolar disordered patients on lithium did not differ in tracking proficiency from those not on lithium; bipolar patients whose lithium status changed from intake to retest also did not display a significant change in pursuit performance.

Adult↗
PubMed1993

Establishing the onset of psychotic illness.

OBJECTIVE: To date, the literature has provided no standardized, replicable method for establishing illness onset. The authors describe a method for dating the first appearance of prodromal signs of psychotic illness, the emergence of an acute episode, and the initiation of treatment seeking. METHOD: Using reports by family and friends about a sample of 141 subjects with first-episode psychosis, the investigators derived a checklist of behaviors describing the evolution of various phases of illness. Supplied with the checklist, clinician pairs independently rated the critical phases in the evolution of illness: first appearance of noticeable symptoms, first appearance of prominent psychotic symptoms, and initiation of treatment seeking. RESULTS: The judges achieved good reliability in assigning age at the first appearance of psychotic symptoms and at initiation of treatment seeking. Judging the beginning of the prodrome proved more difficult. Insidious onset proved as characteristic of affective psychosis as of schizophrenia, while treatment lag--the interval between emergence of acute psychotic symptoms and initiation of treatment seeking--was longer for schizophrenia than for affective psychosis. Onset of schizophrenia occurred earlier in women than in men. Depression with psychotic features appeared earlier in men than women. CONCLUSIONS: Although dating the onset of illness phases is probably feasible, efforts to improve reliability must continue. The study results challenge beliefs about gender differences in age at onset.

Adolescent↗
PubMed1993

Measuring self-perceived role competence among first nations and non native children.

The objective of this research is to develop and test measures of self-perceived academic and social competence among First Nations and non native children. The method used is the analysis of psychometric properties of scales derived from questionnaires administered to First Nations children four culture areas of North America, as well as comparison samples of non native children. The results consist of the reliability coefficients, which fall into a satisfactory range; an internal consistency which increases with age; an agreement between self- and teacher-rated competence which is higher for non native than for native children. In the second grade, the competence scores of the native and non native children were equal. Thereafter, the scores of the native children either declined or remained static, while the non native scores tended to increase. In conclusion, the Flower of Two Soils scales are suitable for children from elementary schools, from First Nations and the majority culture. As children mature, the assessments of competence become an increasingly stable part of their repertoire of self-percepts; asynchronous socialization may adversely affect self-perceived competence.

Adolescent↗
PubMed1992

Season of birth and electrodermal activity in functional psychoses.

The present study examined the association between electrodermal activity (EDA) and season of birth in a sample of first-episode patients with schizophrenia, schizophreniform disorder, and affective disorder with psychotic features, and in a normal control group. Patients with schizophrenia who were born during the season of excess risk (January-April) were less responsive than those born during other times of the year. They had lower skin-conductance levels and fewer skin-conductance responses. No such effects were found in patients with schizophreniform or affective disorder, or in the normal subjects. When compared with the control group, winter-born schizophrenics showed significantly more evidence of hyporesponsivity. In contrast, nonwinter-born patients did not differ from normal subjects in skin-conductance level or number of skin-conductance responses. Schizophreniform patients born during the other seasons of the year were more likely to be hyporesponsive. The above results provide supporting evidence for the validity of the season of birth phenomenon. We hypothesize that a viral infection, or some other perinatal complication associated with winter and early spring births, leads to temporal lobe damage and consequent dysregulation of electrodermal activity in patients with schizophrenia.

Adolescent↗
PubMed1992

A family study of nailfold plexus visibility in psychotic disorders.

It has been proposed that the nailfold subpapillary plexus visibility score (PVS) may be a marker of susceptibility to schizophrenia. To further investigate this hypothesis, we evaluated plexus visibility in a sample of 61 chronic schizophrenics, a large sample of first-episode psychotic patients and their first-degree relatives (50 with schizophrenia, and 51 of their relatives; 29 with schizophreniform disorder, 30 of their relatives; 32 with major depression with psychotic features, 35 of their relatives; 33 with a bipolar disorder with psychotic features, 32 of their relatives), and 169 normal control subjects. Group comparisons demonstrated that (1) the probands with chronic schizophrenia, first episode schizophrenia, and schizophreniform disorder did not differ from one another on PVS; (2) these subjects combined had higher PVS ratings than the other two proband groups and normal subjects combined (who did not differ); and (3) none of the relative groups significantly differed from either one another or the normal subjects. On the other hand, relatives of schizophrenia spectrum probands with high PVS (greater than or equal to 10.0) had higher PVS ratings than the relatives of such probands with low PVS. Patterns of familial correlations suggested that PVS was moderately heritable (0.40). There was no evidence that nonadditive genetic variation influenced the trait.

Adult↗