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Jim van Os

Publications and source records attributed to Jim van Os.

At least 73 records · Page 4Linked to original sources
PubMed2004

Prospective cohort study of cannabis use, predisposition for psychosis, and psychotic symptoms in young people.

OBJECTIVE: To investigate the relation between cannabis use and psychotic symptoms in individuals with above average predisposition for psychosis who first used cannabis during adolescence. DESIGN: Analysis of prospective data from a population based sample. Assessment of substance use, predisposition for psychosis, and psychotic symptoms was based on standardised personal interviews at baseline and at follow up four years later. PARTICIPANTS: 2437 young people (aged 14 to 24 years) with and without predisposition for psychosis. MAIN OUTCOME MEASURE: Psychotic symptoms at follow up as a function of cannabis use and predisposition for psychosis at baseline. RESULTS: After adjustment for age, sex, socioeconomic status, urbanicity, childhood trauma, predisposition for psychosis at baseline, and use of other drugs, tobacco, and alcohol, cannabis use at baseline increased the cumulative incidence of psychotic symptoms at follow up four years later (adjusted odds ratio 1.67, 95% confidence interval 1.13 to 2.46). The effect of cannabis use was much stronger in those with any predisposition for psychosis at baseline (23.8% adjusted difference in risk, 95% confidence interval 7.9 to 39.7, P = 0.003) than in those without (5.6%, 0.4 to 10.8, P = 0.033). The risk difference in the "predisposition" group was significantly greater than the risk difference in the "no predisposition" group (test for interaction 18.2%, 1.6 to 34.8, P = 0.032). There was a dose-response relation with increasing frequency of cannabis use. Predisposition for psychosis at baseline did not significantly predict cannabis use four years later (adjusted odds ratio 1.42, 95% confidence interval 0.88 to 2.31). CONCLUSION: Cannabis use moderately increases the risk of psychotic symptoms in young people but has a much stronger effect in those with evidence of predisposition for psychosis.

Adolescent↗
PubMed2004

Association between short birth intervals and schizophrenia in the offspring.

Pregnancy burdens maternal folate reserves. Postpartum restoration to normal folate values may take up to 1 year. Maternal folate deficiency during early pregnancy has been hypothesized as a cause of schizophrenia in the offspring. We investigated whether the risk of schizophrenia is increased in persons conceived shortly after another birth. A population-based cohort was established of 1.43 million persons born in Denmark between 1950 and 1983, yielding 17.6 million person-years of follow-up. Schizophrenia in cohort members (5095 cases) and their siblings and parents was identified by linkage with the Danish Psychiatric Case Register. Relative risks of schizophrenia were estimated by use of log-linear Poisson regression. As compared to intervals of 45 months and longer, the schizophrenia risk ratio was 1.14 (95% confidence interval [CI], 0.97 to 1.35) for interbirth intervals of up to 15 months, 1.32 (95% CI, 1.12 to 1.56) for intervals of 15 to 17 months, 1.38 (95% CI, 1.18 to 1.61), for intervals of 18 to 20 months and 1.13 (95% CI, 1.00 to 1.29) for intervals of 21 to 26 months. Relative risks did not essentially change after adjustment for age, sex, calendar year of diagnosis, maternal and paternal age, history of mental illness in a parent or sibling, sibship size, place of birth, and distance to younger sibling. These results show an association between short birth intervals and schizophrenia in the offspring. Although maternal folate depletion may play a role in this association, we cannot rule out other explanations such as maternal stress during pregnancy and childhood infections.

Adult↗
PubMed2004

Multiple dimensions of familial psychopathology affect risk of mood disorder in children of bipolar parents.

The aim of our study was to determine whether familial loading of unipolar disorder, bipolar disorder, and substance use disorder are associated with DSM-IV mood disorders in adolescents at risk for bipolar disorder. One hundred and forty adolescents aged 12-21 years of 86 bipolar parents participated in the study. Lifetime DSM-IV diagnoses of the bipolar offspring were assessed with the Schedule for Affective Disorders and Schizophrenia for School Age Children Kiddie-SADS-Present and Lifetime Version (SADS-PL). Parents were interviewed using the Family History Research Diagnostic Criteria (FH-RDC) which were used to calculate a continuous familial loading score (FL) for unipolar disorder, bipolar disorder, and for substance use disorder in first- and second-degree relatives of the adolescents. FL for unipolar disorder and substance use disorder were strong and independent predictors for lifetime mood disorders in the adolescents. The gender adjusted hazard ratios for mood disorders in the children were 1.5 (95% confidence interval (CI) = 1.2-2.0) for FL of unipolar disorder and 1.8 (95% CI = 1.3-2.4) for FL of substance use disorder. Expression of mood disorders in children of bipolar parents varies with the degree of additional FL of unipolar disorder and substance use disorder in the extended family.

Adolescent↗
PubMed2004

Income inequality at neighbourhood level and quality of life--a contextual analysis.

OBJECTIVE: Associations were examined between neighbourhood income inequality and neighbourhood socioeconomic deprivation on the one hand and (mental) health related quality of life (QoL) on the other, in Maastricht, the Netherlands. METHODS: Three different data sources were used: 1) neighbourhood socioeconomic indicators, 2) house prices per postal code area aggregated to an inequality measure at neighbourhood level, and 3) individual data measured in a family cohort study. Maastricht families with children aged approximately 11 years received questionnaires including the parents' QoL and family socioeconomic status (response rate: 60%). Multilevel analyses were conducted using neighbourhood level, family level, and individual level data. RESULTS: Income inequality at neighbourhood level was not associated with QoL, whereas socioeconomic deprivation was associated with environment-related QoL. CONCLUSION: The relative income hypothesis, according to which it is the contrast in deprivation rather than the absolute level of deprivation that influences health outcomes, does not hold at the neighbourhood level. Income inequality may only have an effect in larger areas containing sufficient socioeconomic contrast.

Adult↗
PubMed2004

Improvements in stable patients with psychotic disorders switched from oral conventional antipsychotics therapy to long-acting risperidone.

Recent meta-analytic work suggests atypical antipsychotics may be clinically superior to conventional antipsychotics, although many stable patients remain on conventional antipsychotic treatment. A long-acting atypical agent may benefit patients in realms of both advanced medication delivery and mechanism of action. In a multicentre, open-label study of 725 patients with schizophrenia or schizoaffective disorder, patients received 25-75 mg of long-acting risperidone every 2 weeks for up to 50 weeks, with performance of standard safety and efficacy assessments. Data are presented on stable patients receiving oral conventional antipsychotics at study entry. In the 46 (6.3%) stable patients receiving oral conventional antipsychotics (followed between 6 months and 1 year; mean 468 days), mean (SD) Positive and Negative Syndrome Scale (PANSS) total score improved from 73.1+/-17.2 to 64.5+/-18.2 (P=0.0006). Clinical improvement of > or =20%, > or =40% or > or =60% reduction in PANSS total score occurred in 49%, 29% and 10% of stable patients, respectively. Extrapyramidal Symptom Rating Scale subjective ratings and objective physician ratings (parkinsonism) decreased significantly (P<0.05). The hypothesis that switching stable patients treated with oral conventional antipsychotics to long-acting risperidone may result in significant improvements in psychiatric and movement disorder symptomatology merits further investigation.

Administration, Oral↗
PubMed2004

Confirmation of synergy between urbanicity and familial liability in the causation of psychosis.

OBJECTIVE: This study replicated a previous report that there may be substantial synergism between urbanicity (a proxy environmental risk factor) and familial clustering of psychotic disorder (a proxy genetic risk factor). METHOD: The amount of synergism was estimated from the additive statistical interaction between urbanicity of place of birth and family history of schizophrenia or family history of any severe mental disorder in a population-based Danish cohort of 1,020,063 individuals. RESULTS: There was significant interaction between urbanicity and family history; between 20% and 35% of individuals who had been exposed to both of these risk factors had schizophrenia possibly because of their synergistic effects. CONCLUSIONS: The results suggest that a substantial proportion of the population morbidity force of schizophrenia may be the result of gene-environment interactions associated with urbanicity.

Adult↗
PubMed2003

Sex differences in symptoms of psychosis in a non-selected, general population sample.

BACKGROUND: Little is known about sex differences in psychosis beyond the borders of clinical disorder. METHODS: A general population sample of 7,076 subjects was assessed using the Composite International Diagnostic Interview, in order to explore sex differences in the prevalence of any positive and negative symptoms of psychosis, and to examine to what degree any differences could be explained by differences in level of affective symptoms. RESULTS: Male sex was associated with higher prevalence of negative symptoms (OR = 1.6, 95% CI = 1.0, 2.5), independent of differences in affective symptoms and presence of DSM-III-R psychotic disorder. Women had higher rates of positive psychotic experiences (OR = 0.8, 95% CI = 0.7, 0.9), but this difference disappeared after adjustment for depressive symptoms (adjusted OR = 1.2, 95% CI = 0.9, 1.5). CONCLUSION: The sex differences in psychopathology that are seen in schizophrenia are expressed beyond the clinical phenotype, suggesting sex-dependent continuous and normal variation of several psychosis dimensions. The higher rates of positive psychotic experiences seen in women may be secondary to differences in the rate of affective symptoms.

Adult↗
PubMed2003

Sex differences in psychosis: normal or pathological?

BACKGROUND: Schizophrenia first appears in adolescence, in boys at an earlier age than girls. The interpretation of this key epidemiological finding crucially depends on whether similar age-related sex differences exist in the expression of associated, subclinical psychosis-like experiences. METHODS: Findings are based on a population sample of 2548 adolescents and young adults aged 17-28. Subjects were assessed with the core psychosis sections on delusions and hallucinations of the Munich-Composite International Diagnostic Interview. RESULTS: The risk of subclinical psychotic experiences was significantly higher for males in the younger half of the cohort (17-21 years), but similar in the older half (22-28 years). CONCLUSIONS: These findings suggest that normal maturational changes in adolescence with differential age of onset in boys and girls cause the expression of psychosis, the extreme of which is schizophrenia.

Adolescent↗
PubMed2003

Searching for a structural endophenotype in psychosis using computational morphometry.

Structural cerebral abnormalities are frequently observed in schizophrenia. These abnormalities may indicate vulnerability for the disorder, as evidenced by reports of familial clustering of measures identified through region-of-interest analyses using manual outlining procedures. We used computational morphometry to detect structural differences within the entire brain to further examine possible structural endophenotypes. Magnetic resonance imaging scans were obtained in 31 psychotic patients, 32 non-psychotic first-degree relatives of psychotic patients and 27 healthy controls. The images were processed using an automated procedure, yielding global grey matter, white matter, CSF and total brain volume. The relative distribution of grey matter was compared between groups on a clustered-voxel basis. Global grey matter and total brain volume did not differ between the groups. White matter volume was significantly higher and CSF volume significantly lower in relatives compared to both cases and controls. The clustered-voxel based group comparison yielded evidence for significant grey matter deficits in fronto-thalamic-cerebellar regions, in psychotic patients, whereas the most prominent deficits in relatives involved the cerebellum. Patients with psychosis and first-degree healthy relatives of patients with psychosis show cerebellar abnormalities, which may constitute a marker of genetic transmission.

Adolescent↗
PubMed2003

Cannabis use and dimensions of psychosis in a nonclinical population of female subjects.

OBJECTIVE: The aim of the present study was to explore the pattern of associations between cannabis use and dimensions of psychosis in a nonclinical population of female subjects. METHOD: The Community Assessment of Psychic Experiences (CAPE), a 42-item self-report questionnaire that evolved from the Peters et al. Delusions Inventory [Schizophr. Bull. 25 (1999) 553], was used to measure dimensions of psychosis in a sample of undergraduate female students (n=571). The participants were also asked to complete a self-report questionnaire collecting information on substance use. RESULTS: Three correlated dimensions of positive, negative and depressive experiences were identified using principal components factor analysis. Frequency of cannabis use was independently associated with the intensity of both positive and negative psychotic experiences. No significant association was found between cannabis use and the depressive dimension, or between alcohol use and any of the three positive, negative and depressive dimensions. CONCLUSION: This cross-sectional study supports the hypothesis that exposure to cannabis may induce the emergence of positive psychotic symptoms in subjects without clinical psychosis, and additionally suggests that cannabis users exhibit greater levels of negative symptoms. Prospective studies are required to explore the direction of causality and the impact of cannabis on the course of psychotic experiences in subjects from the general population.

Adolescent↗
PubMed2003

Childhood social and early developmental factors associated with mental health service use.

BACKGROUND: The aim of this study was to determine the influence of family and child variables on the pathway to mental health care in children. METHODS: A blinded, matched case control study was conducted, involving a retrospective analysis of prospectively collected data from routine examinations at the Youth Health Care Division from the Municipal Health Centre Maastricht (YHCD), where all children in a geographically defined area from foetal life through to age 19 years are periodically screened. The sample included 400 children, 80 referred to the Community Mental Health Centre in Maastricht and 320 matched controls, aged 6-13 years. RESULTS: The most potent risk factors associated with mental health service use were: being small at birth, having a younger mother at delivery, living in a one-parent family, having a divorced mother and/or unemployed father, observations of externalising behaviour and/or motor developmental problems, speech problems and experiencing several adverse family circumstances. The group of variables pertaining to the family (e. g. one-parent family, parental mental health problems, etc.) influenced mental health service independently of the group of variables pertaining to the child (e. g. birth length, speech problems, etc.) and vice versa. Several combinations of risk factors, under realistic prevalence estimates, had positive predictive values of up to 26 %. CONCLUSION: Pathways to child psychiatric care are heavily influenced by the child's family environment as well as by deviance in social, motor and speech development. Independence of child developmental effects suggests these are not merely on the causal pathway between adverse family environment and psychiatric service use outcome. Combinations of risk factors may be useful to develop a screening approach with the possibility of early prevention.

Adolescent↗
PubMed2003

Children's mental health service use, neighbourhood socioeconomic deprivation, and social capital.

BACKGROUND: There is accumulating evidence that the shared social environment at the neighbourhood level exerts significant effects on health over and above individual level variables. The aim of this study was to assess the interactive influence of neighbourhood measures of socioeconomic deprivation and social capital (i. e. informal social control, social cohesion and trust) on children's mental health service use, independent of individual level confounders. METHODS: Two different data sources were used: 1) individual socioeconomic measures, derived from a case-control study in which case/control status indicated mental health service use or not, and 2) neighbourhood measures of socioeconomic deprivation and social capital. The data were subjected to multilevel logistic regression analysis. RESULTS: Children living in more deprived neighbourhoods run a higher risk of coming into contact with mental health care services. The social capital variables (informal social control and social cohesion and trust) did not exert main effects, but strong trust and social cohesion between citizens in the neighbourhood mitigated the risk-increasing effect of socioeconomic deprivation on children's mental health service use. CONCLUSIONS: The deleterious effects of socioeconomic deprivation on mental health service use in children are sensitive to the context of cohesion and trust in neighbourhoods. Effects of deprivation on children's mental health cannot be interpreted without taking into account the context of social capital.

Catchment Area, Health↗
PubMed2003

Mediators of neighbourhood socioeconomic deprivation and quality of life.

OBJECTIVE: We examined associations between neighbourhood socioeconomic deprivation and health-related quality of life, and estimated the mediating effects of individual-level lifestyle, housing, and perception of the neighbourhood environment. METHODS: Two different data sources were used: 1) neighbourhood- level objective socioeconomic indicators, and 2) individual-level questionnaires from a community survey (response rate: 48%) to assess quality of life, neighbourhood perceptions, housing variables, and lifestyle. Multilevel analyses were conducted using both neighbourhood-level and individual-level data. RESULTS: Neighbourhood-level socioeconomic deprivation was associated with two aspects of individual-level quality of life: mental health and perceived health. Individual-level neighbourhood perceptions regarding social cohesion mediated these associations. Lifestyle also had mediating effects. CONCLUSION: Neighbourhood socioeconomic deprivation variables may impact on the individual through cognitive mechanisms that are associated with appraisal of the wider social environment.

Adult↗
PubMed2003

Children's health-related quality of life, neighbourhood socio-economic deprivation and social capital. A contextual analysis.

Neighbourhood objective socio-economic indicators and community-reported subjective measures of social capital were examined in relation to children's health-related quality of life in the Netherlands. Three different data-sources were used: (1) objective neighbourhood socio-economic indicators, (2) subjective neighbourhood data on social capital, and (3) individual data of a family cohort study, including questions on children's health-related quality of life, and family socio-economic status. Multilevel analyses were conducted using both neighbourhood level and individual level data. Neighbourhood socio-economic status and social capital were associated. Measures of socio-economic deprivation and social capital were both non-specifically associated with children's general health and satisfaction, independent of possible individual-level confounders. However, children's mental health and behaviour were specifically associated with one aspect of social capital, the degree of informal social control in the neighbourhood.

Child↗
PubMed2003

Alterations in theory of mind in patients with schizophrenia and non-psychotic relatives.

OBJECTIVE: It has been proposed that alterations in theory of mind underlie specific symptoms of psychosis. The present study examined whether alterations in theory of mind reflect a trait that can be detected in non-psychotic relatives of patients with schizophrenia. METHOD: Participants were 43 patients with schizophrenia or schizoaffective disorder, 41 first-degree non-psychotic relatives and 43 controls from the general population. Theory of mind was assessed using a hinting task and a false-belief task. RESULTS: There was a significant association between schizophrenia risk and failure on the hinting task (OR linear trend = 2.01, 95% CI: 1.22-3.31), with relatives having intermediate values between patients and controls. Adjustment for IQ and neuropsychological factors reduced the association by small amounts. The association between schizophrenia risk and failure on the false-belief tasks was not significant. CONCLUSION: Changes in theory of mind are associated with schizophrenia liability. General cognitive ability and neuropsychological measures seem to mediate only part of this association.

Adult↗
PubMed2003

When does experience of psychosis result in a need for care? A prospective general population study.

Not all individuals with experience of psychosis develop a need for care. The present study investigated differences in coping strategies and associated levels of perceived control over psychotic symptoms, in relation to need for care status. The influence of coping on need for care was assessed in 47 individuals incident for psychosis in a general population sample of 4,722. Need for care was associated with severity of psychotic experiences rather than associated distress, mean level of control, or average number of coping strategies used. Qualitative differences were apparent, however, in that those who resorted to the strategy of symptomatic coping (a coping strategy characterized by going along with and indulging in symptoms) experienced less control over their symptoms (odds ratio [OR] = 0.79, 95% confidence interval [CI]: 0.63-0.98) and had a higher probability of need for care (OR = 6.07, 95% CI: 1.94-18.95). The results suggest that qualitative differences in self-initiated coping modify the risk for need for care and subsequent patient status in those who experience psychotic symptoms and point to the possible importance of early coping-based interventions.

Adaptation, Psychological↗