Biomedical subjects

Robert J van den Bosch

Publications and source records attributed to Robert J van den Bosch.

15 recordsLinked to original sources

PubMed2006

Negative association between a history of obstetric complications and the number of neurological soft signs in first-episode schizophrenic disorder.

We examined the relationship between a history of obstetric complications (OCs) and the number of neurological soft signs (NSS) in a group of 132 patients experiencing their first episode of psychosis. We measured NSS by means of a comprehensive standardized assessment and gained information on a selection of nine OCs from the patient's mother. Contrary to our expectations we found significantly more NSS in the group of patients without a history of OCs. This effect was independent of medication in the group of patients with a schizophrenic disorder, but not in the entire group. It is possible that the patients with a history of OCs carry fewer genes for schizophrenia (and NSS) and 'needed' the OCs to develop schizophrenia.

Adult↗

PubMed2006

Predictive value of cognition for different domains of outcome in recent-onset schizophrenia.

The aim of this study was to see whether and how cognition predicts outcome in recent-onset schizophrenia in a large range of domains such as course of illness, self-care, interpersonal functioning, vocational functioning and need for care. At inclusion, 115 recent-onset patients were tested on a cognitive battery and 103 patients participated in the follow-up 2 years after inclusion. Differences in outcome between cognitively normal and cognitively impaired patients were also analysed. Cognitive measures at inclusion did not predict number of relapses, activities of daily living and interpersonal functioning. Time in psychosis or in full remission, as well as need for care, were partly predicted by specific cognitive measures. Although statistically significant, the predictive value of cognition with regard to clinical outcome was limited. There was a significant difference between patients with and without cognitive deficits in competitive employment status and vocational functioning. The predictive value of cognition for different social outcome domains varies. It seems that cognition most strongly predicts work performance, where having a cognitive deficit, regardless of the nature of the deficit, acts as a rate-limiting factor.

Activities of Daily Living↗

PubMed2006

Niacin skin flushing in schizophrenic and depressed patients and healthy controls.

This study compares the skin reactions to the niacin flushing test of 16 schizophrenic patients with those of 17 depressed patients and 16 healthy controls. Methyl nicotinate (niacin) in a concentration of 0.1 M was applied to the forearm for 5 min. Significant differences could be observed between the group of schizophrenic patients (less flushing) in comparison to the other groups. There were no statistical differences in niacin flushing between patients with depression and healthy controls. Gender, age and the use of antipsychotic agents did not appear to be confounders. The differences in flushing within the group of schizophrenic patients were striking, however. Most patients showed little or no flushing, but some patients reacted strongly. Although the three groups could be differentiated by the niacin flushing test, to develop a reliable clinical application of this test, further research is necessary.

Adult↗

PubMed2006

Deviant strategy on The Modified Six Elements Test in patients with schizophrenia.

Impaired executive functioning is found in a considerable proportion of schizophrenia patients. Neuropsychological tests are originally designed to measure the behavior of neurological patients and may therefore miss psychiatry-related cognitive deficits. Qualitative information on tests for executive functioning is important in psychiatric populations. The Modified Six Elements Test (MSET) is a planning test that consists of 6 tasks, for which subjects have limited time and have to obey to switching rules. This study concerns a qualitatively different approach schizophrenia patients use on the MSET, and its relationship with cognitive measures. MSET scores and strategies of schizophrenia patients were compared to those of healthy controls, closed-head-injury patients, and peripheral injury patients. Also, schizophrenia patients and healthy controls were compared on verbal memory and vigilance. Schizophrenia patients finish fewer assignments on the MSET, receive a lower profile score compared to healthy controls, and use a different strategy on the test compared to the other groups. They also perform below healthy controls on the tests for verbal memory and vigilance. Use of the different strategy in schizophrenia patients was related to impaired cognitive functioning. An interesting strategy used by schizophrenia patients on the MSET appears to be indicative of impaired cognitive functioning. This strategy may be a compensatory strategy to spare cognitive resources. It could also be the result of a concrete interpretation of the test instructions.

Adolescent↗

PubMed2006

Evaluation of the subjects' response to antipsychotics questionnaire.

The present study reports on the development of a new self-administered instrument to assess patients' responses to antipsychotic medication. The Subjects' Response to Antipsychotics (SRA) Questionnaire is a 74-item instrument with eight scales (Recovery, Weight Gain, Sexual Anhedonia, Sedation, Affective Flattening, Extrapyramidal Side-Effects, Diminished Sociability and Increased Sleep), and a total adverse responses score including additional items. Psychometric aspects were examined in a study of 320 inpatients and outpatients showing good internal consistency, reproducibility and external validity. Concordance with other instruments claiming to measure the subjective response is low, suggesting that the instruments measure different concepts. The SRA Questionnaire appears to be a reliable and efficient way of measuring patients' subjective responses to antipsychotic medication.

Adult↗

PubMed2005

Measuring the executive functions in schizophrenia: the voluntary allocation of effort.

INTRODUCTION: Executive functioning reflects not only what a patient does, but also how he does it or whether he does it at all [Lezak MD. The problem of assessing executive functions. Int. J. Psychol. 17 (1982) 281]. Standard test procedures strongly prompt subjects to certain behavior, so that initiative and the amount of voluntary effort one is willing to invest are therefore not being adequately assessed. METHODS: We developed the Cognitive Effort Test (CET); a test for executive functioning specifically aimed at measuring subject's free initiatives, and the amount of effort they invest voluntarily. It is a complex planning task, and performance is being judged by three subscales: Initiative, Planning, and Workload. 36 schizophrenia patients and 30 healthy controls were tested with the CET, and a battery of other cognitive tests (executive functioning, memory, attention and psychomotor speed) was added to investigate construct and divergent validity. Negative symptoms were also recorded (predictive validity). RESULTS: Patients scored below controls on Planning and Workload, but not on Initiative. The CET was significantly related to other tests for cognition but not to negative symptoms. CET Planning and Workload predicted group membership (patients-controls) better than the other tests for executive functioning combined. CONCLUSION: The CET appears to be a clinically useful test that measures an aspect of schizophrenia that is not being assessed by existing tests, presumably the voluntarily allocation of effort.

Adolescent↗

PubMed2005

Predominant role of the 9-hydroxy metabolite of risperidone in elevating blood prolactin levels.

OBJECTIVE: The atypical antipsychotic risperidone significantly raises plasma prolactin levels in patients, but clozapine, olanzapine, and quetiapine do not. The differences in neuroendocrine response may be connected with the metabolism of the medications. The authors examined the contributory role of risperidone's active metabolite 9-hydroxy-risperidone by measuring plasma concentrations of risperidone, 9-hydroxy-risperidone, and prolactin. METHOD: Blood samples taken from 25 patients with psychotic disorders following 6 weeks of treatment with risperidone (mean dose=3 mg/day) were examined. Mean plasma concentrations of risperidone, 9-hydroxy-risperidone, and prolactin were 4.6, 19.4, and 49.3 ng/ml, respectively. RESULTS: The oral dose of risperidone correlated significantly with plasma concentrations of risperidone, 9-hydroxy-risperidone, active moiety, and prolactin. The plasma concentration of 9-hydroxy-risperidone, but not of risperidone, correlated significantly with increases in plasma prolactin. CONCLUSIONS: These data suggest that the 9-hydroxy metabolite plays a predominant role in risperidone's effect on prolactin release.

Adolescent↗

PubMed2004

What is measured by verbal fluency tests in schizophrenia?

INTRODUCTION: Schizophrenia patients perform below the norm on verbal fluency tests. The causes for this are unknown, but defective memory, executive functioning and psychomotor speed may play a role. METHOD: We examined 50 patients with schizophrenia and related disorders, and 25 healthy controls with a cognitive test battery containing tests for verbal memory, executive functioning and psychomotor speed, and a categorical fluency test. RESULTS: Patients obtained significantly lower test results than the controls on most cognitive measures including the verbal fluency test. During the fluency test, they formed as many clusters, and switched as often between clusters as the controls did, but they generated fewer words per cluster. Interestingly, in the control group, fluency performance was predicted by memory and executive functioning, but not by psychomotor speed. In patients, verbal fluency was predicted by psychomotor speed, but not by memory or executive functioning. DISCUSSION: We conclude that psychomotor speed could be a crucial factor in cognition, and its influence on cognitive test performance should be considered in schizophrenia research. Furthermore, these data illustrate the importance of qualitative analysis of cognitive impairments in schizophrenia patients, as traditional cognitive tests often only provide quantitative information.

Adult↗

PubMed2004

A randomized open-label study of the impact of quetiapine versus risperidone on sexual functioning.

OBJECTIVE: To compare sexual functioning in patients treated with quetiapine or risperidone. METHODS: This open-label study included patients with schizophrenia or a related psychotic illness who were randomized to quetiapine (200-1200 mg/d) or risperidone (1-6 mg/d) for 6 weeks. Sexual dysfunction was assessed by a semistructured interview, the Antipsychotics and Sexual Functioning Questionnaire (ASFQ), based upon the Utvalg for Kliniske Undersogelser (UKU). RESULTS: Four of 25 quetiapine-treated patients (16%) and 12 of 24 risperidone-treated patients (50%) reported sexual dysfunction (chi 2 = 6.4; df = 1; P = 0.006) on the ASFQ. Six patients (11.7%; 4 on risperidone, 2 on quetiapine) spontaneously reported sexual dysfunction. The mean+/-SD dose was 580+/-224 mg/d for quetiapine and 3.2 +/- 1.3 mg/d for risperidone. Mean +/- SD prolactin levels in quetiapine- and risperidone-treated patients were 13.8 +/- 17.9 and 57.7 +/- 39.7 ng/mL, respectively. CONCLUSION: Sexual dysfunction was less common in patients treated with quetiapine than with risperidone. Direct questioning about sexual functioning is necessary to avoid underestimating the frequency of sexual side effects in patients with schizophrenia and related psychotic disorders.

Adolescent↗

PubMed2003

Learning (potential) and social functioning in schizophrenia.

Cognitive dysfunction in schizophrenia has well-known functional consequences. The ability to learn (learning potential) may be an important mediator. This study examines the relationship between learning and functional status in schizophrenia patients before and after participation in a rehabilitation program. We reasoned that learning is a broad construct, encompassing controlled, effortful as well as automatic (learning by doing) mechanisms, called explicit and implicit learning, respectively. Both types of learning ability are important in daily life. The study included 44 medicated schizophrenia patients and 79 healthy controls. We included measures of implicit and explicit learning as well as measures of the cognitive domains for which significant relationships with functional outcome have been established: immediate and secondary verbal memory, card sorting and vigilance. Learning potential and the patient's 'learner status' were also assessed. The results show that learning, as assessed by measures of explicit and implicit learning and learning potential, was not associated with social functioning or rehabilitation outcome. The highest correlations between cognitive functioning and social functioning were found for more or less 'static' performance measures when they were assessed for a second time with or without instructions on how to do the test. Optimized cognitive performance (i.e. performance after instruction or training) seems to be a better predictor of complex domains of functioning than naive or everyday performance.

Adult↗

PubMed2003

Long-term memory deficits in schizophrenia: primary or secondary dysfunction?

Long-term memory impairment is often found in schizophrenia. The question remains whether this is caused by other cognitive deficits. One hundred eighteen first-episode patients were compared with 45 control participants on several memory tasks. The role of processing speed and central executive functions on memory performance was examined with regression analysis for all participants and for patients separately. Deficits were found in general verbal learning performance and retrieval in episodic memory and semantic memory. Processing speed reduced disease-related variance in all memory variables. Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients. The amount of explained variance, however, is small, especially in general verbal learning performance.

Adult↗

PubMed2003

Cognitive deficits and social functioning in schizophrenia: a clinical perspective.

Impaired social functioning is one of the diagnostic features of schizophrenia. Cognitive functioning is also often impaired in several domains. Meta-analysis has shown a predictive value of cognition for a variety of domains related to social functioning (Green, Kern, Braff, & Mintz, 2000). The significance of these findings for clinical practice has remained largely uninvestigated, however, and is therefore taken up here. We investigated verbal memory, attention and executive functioning in 52 schizophrenia patients. Social functioning was assessed for different types of social roles. The percentages of cognitive and social impairments in our group were assessed according to clinical principles, normally used to judge an individual patient. A possible predictive relationship between cognition and social functioning was studied on the basis of these clinical criteria. A large proportion of patients showed impairments in both cognitive functioning and social functioning. However, the clinical method resulted in a successful prediction of social functioning in only 21-69% of the cases. Social functioning and cognitive functioning were impaired in a large proportion of patients, but were largely independent from each other. Since relationships between cognition and social functioning are weak, assessment procedures are inconsistent and possibly not optimally adjusted to the psychiatric population, the clinical relevance of cognitive testing in order to predict social functioning is as yet questionable.

Adolescent↗

PubMed2002

Schizophrenic patients without neuropsychological deficits: subgroup, disease severity or cognitive compensation?

Some schizophrenic patients do not show clinically relevant cognitive deficits. The question remains whether this represents the existence of an etiologically different subgroup, a general effect of disease severity or whether their cognitive deficits do not reach a clinical threshold due to a greater cognitive compensation ('brain reserve') capacity. A group of 23 out of 118 first onset patients was identified as cognitively normal (CN). The cognitive profile of these patients was compared with that of 45 healthy controls. Next these patients were compared with the cognitively impaired (CI) patients on obstetric complications (OCs), premorbid adjustment, age at onset, Positive and Negative Syndrome Scale ratings, social functioning and substance abuse. In addition both groups were compared on intelligence and educational level as indirect indicators of cognitive compensation capacity. There were no differences in OCs, premorbid adjustment, age at onset, psychopathology or substance abuse between the two patient groups. There was a significant difference in social functioning, which is a consequence rather than a cause of cognitive deficits. However, the CN patients scored significantly higher on measures of intelligence and educational level than the CI patients. This suggests that a difference in cognitive compensation capacity could explain the existence of a CN patient group.

Adolescent↗

PubMed2002

A controlled trial of cognitive remediation in schizophrenia.

A randomized, controlled trial of a 3-month cognitive remediation program was examined for its efficacy at ameliorating deficits in social and emotion perception in 42 hospitalized patients with schizophrenia. Generalization of training effects to attention, memory, and executive functioning was also examined. The program included an eclectic mix of self-instruction, memory enhancement, inductive reasoning, and compensatory training procedures, while the control condition included participation in a leisure group that was matched to the experimental group for staff involvement time. Patient care management, including type and dose of antipsychotic medication, remained constant throughout the study period. The results indicated that the cognitive training program improved emotion perception, with some evidence of generalization to measures of executive functioning; other areas of neurocognitive functioning were largely unaffected. While cognitive training programs may improve targeted areas of neurocognitive processing, broad generalization effects to domains outside those targeted for intervention are not likely concomitants.

Adult↗

PubMedDate not supplied

A randomized open-label comparison of the impact of olanzapine versus risperidone on sexual functioning.

The objective of this study was to compare sexual functioning in patients treated with olanzapine or risperidone. This open-label trial included 46 patients randomized to olanzapine (5-15 mg/d) or risperidone (1-6 mg/d) for 6 weeks. We used sexual dysfunction was assessed by a semistructured interview based on the items of the UKU side effect rating scale. Three olanzapine-treated patients (12.0%), compared with 11 risperidone-treated patients (52.4%), reported sexual dysfunctions (p = .008) in the semistructured interview. Only 4 patients (8.7%) spontaneously reported sexual dysfunction. The mean dose was 9.4 mg/d for olanzapine and 3.4 mg/d for risperidone. The mean (+/-SD) prolactin levels (ng/mL) in olanzapine-and risperidone-treated patients were 25.1 (+/- 23.5) and 43.5 (+/- 26.1), respectively. Less sexual dysfunction occurred in the group treated with olanzapine compared with the risperidone group. Direct questioning about sexual functioning is necessary to avoid underestimating the frequency of sexual side effects in patients with schizophrenia and related psychotic disorders.

Adult↗