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Biomedical subjects

Jim van Os

Publications and source records attributed to Jim van Os.

At least 19 recordsLinked to original sources
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

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↗
PubMed2003

Do urbanicity and familial liability coparticipate in causing psychosis?

OBJECTIVE: The urban environment and familial liability are risk factors for psychotic illness, but it is not known whether a biological synergism exists between these two proxy causes. METHOD: The amount of biological synergism between familial liability (defined as a family history of delusions and/or hallucinations necessitating psychiatric treatment) and a five-level rating of population density of place of residence was estimated from the additive statistical interaction in a general population risk set of 5,550 individuals. RESULTS: Both the level of urbanicity (adjusted summary odds ratio=1.57, 95% CI=1.30-1.89) and familial liability (adjusted odds ratio=4.59, 95% CI=2.41-8.74) increased the risk for psychotic disorder, independently of each other. However, the effect of urbanicity on the additive scale was much larger for individuals with evidence of familial liability (risk difference=2.58%) than in those without familial liability (risk difference=0.40%). An estimated 60%-70% of the individuals exposed to both urbanicity and familial liability had developed psychotic disorder because of the synergistic action of the two proxy causes. CONCLUSIONS: Given that familial clustering of psychosis is thought to reflect the effect of shared genes, the findings support a mechanism of gene-environment interaction in the causation of psychosis.

Adult↗
PubMed2002

Formation of delusional ideation in adolescents hearing voices: a prospective study.

Previous work suggests that auditory hallucinations in children and adolescents occur frequently in the absence of psychotic illness, although a number of such children go on to develop more severe psychotic symptomatology and need for care. We examined prospectively what factors are associated with formation of delusions in adolescents who are hearing voices. Eighty adolescents (mean age 12.9 years, SD = 3.1) who reported hearing voices were examined at baseline and followed-up three times over a period of 3 years. Fifty percent were receiving professional care, but 50% were not in need of care. Baseline measurement of voice appraisals, attributions, psychopathology, global functioning, dissociation, stressful life events, coping mechanisms, and receipt of professional care were used as predictors of delusion formation, measured as a score of 6 or greater on the extended BPRS items: "suspiciousness," "unusual thought content" and "grandiosity." Thirteen children (16%) displayed evidence of delusional ideation over at least one of the three follow-up periods, of which seven (9%) de novo. Adjusting for presence of baseline delusional ideation, delusion formation over the follow-up period was associated with baseline voice appraisals and attributions such as tone of the voice (hazard ratio voice "variably friendly and hostile" compared to "always friendly": HR = 6.8, 95% CI: 1.1, 41.0), perceived location of the voice (outside vs. inside head: HR = 2.9, 95% CI: 1.0, 8.7), and whether the voice resembled that of a parent (HR = 3.5, 95% CI: 1.0, 12.0); baseline BPRS anxiety/depression (HR = 6.4, 95% CI: 1.9, 21.4), baseline BPRS disorganization (HR = 5.0, 95% CI: 0.98, 26.1) and the baseline amount of reported recent stressful life events (HR continuous life events score: 1.8, 95% CI: 1.0, 3.3). In addition, in older children, the perceived influence of the voices on emotions and behavior was strongly associated with delusion formation (HR = 5.1, 95% CI: 1.0, 25.9). Delusion formation in children hearing voices may be responsive to triggering events and facilitated by feelings of anxiety/depression. The results also highlight the role of attributions associated with external sources, authority figures, perceived influence or "power" over the person, as well as emotional appraisal processes and cognitive disorganization.

Adolescent↗
PubMed2002

Social and clinical consequences of cognitive deficits in early psychosis: a two-year follow-up study of first-admitted patients.

OBJECTIVE: To explore whether baseline memory and executive deficits predicted poor social and clinical outcome over the 2 years following a first admission for psychosis, regardless of categorical diagnosis. METHOD: Cognitive functioning was assessed in first-admitted subjects with psychosis (n=35) with a neuropsychological battery of tests measuring executive, language and memory functions. Social and clinical outcome were assessed at 6-monthly intervals over a two-year follow-up using multiple sources of information. RESULTS: A dose-response relationship was found between visual and verbal memory performance at first admission and clinical outcome over the 2-year follow-up: the poorer the memory performance, the more likely the risk of presenting with psychotic symptoms and rehospitalization. Poor baseline performance on the WCST executive function predicted better medication adherence. No association was found between cognitive performance and occupational or residential outcome. CONCLUSION: Cognitive performance was a better predictor of clinical than social outcome in this sample of first-episode patients. The association between cognitive deficits and poor social outcome may be more marked in subjects with chronic psychosis than in first-episode subjects. The finding that cognitive deficits predict better medication adherence is in need of further exploration.

Activities of Daily Living↗
PubMed2002

Psychotic symptoms in non-clinical populations and the continuum of psychosis.

A growing body of evidence suggests that delusional or hallucinatory experiences are much more frequent in subjects from the general population than the prevalence of cases of psychotic disorders, thereby suggesting the existence of a symptomatic continuum between subjects from the general population and clinical cases of psychosis. Exploring the risk factors modulating the expression of psychosis-like signs in non-clinical populations may better contribute to elucidate the etiology of psychosis than research restricted to subjects at the endpoint of the distribution of the psychotic dimension. The aim of this paper is to briefly review research investigating the distribution of psychotic symptoms in non-clinical populations, the developmental aspects of psychosis proneness, and the outcome characteristics of psychosis-prone subjects.

Adolescent↗
PubMed2002

Does the urban environment independently increase the risk for both negative and positive features of psychosis?

BACKGROUND: Psychotic disorders are more common in urban environments. It is not known whether the increase in risk applies to both the positive and negative dimensions of psychosis. METHODS: In a random general population sample of 7076, measures of positive and negative symptoms of psychosis were constructed using Composite International Diagnostic Interview (CIDI) data. Three CIDI observed items of flat affect, retarded speech and retarded movement served as indicators of a negative symptom variable. RESULTS: Both negative and positive symptoms of psychosis were, independent of each other, associated with a five-level measure of population density of place of residence (adjusted OR negative symptoms: 1.42, 95 % CI: 1.18, 1.71; adjusted OR positive symptoms: 1.19, 95 % CI: 1.13, 1.24). These associations remained after exclusion of vulnerable individuals with any lifetime psychiatric disorder (n = 2910), any lifetime psychiatric treatment (n = 1352) and history of psychosis in the parents (n = 142). CONCLUSIONS: An environmental risk factor associated with urbanicity may act in early life to non-specifically influence risk for both negative and positive experience of psychosis, regardless of whether a formal psychiatric disorder is diagnosable.

Adolescent↗
PubMed2002

Determinants of occurrence and recovery from hallucinations in daily life.

BACKGROUND: Data related to the dynamics of hallucinatory experiences of patients suffering from schizophrenia are scarce. Detecting antecedent conditions and coping strategies may aid development of targeted psychological interventions. METHOD: We studied hallucinating and non-hallucinating patients suffering from schizophrenia spectrum disorder (n = 57), and non-schizophrenic severe mentally ill patients with depression (n = 37). Data were collected using the Experience Sampling Method (ESM) over a period of 1 week. Contingent on a randomly signalling beep, subjects filled in reports of ongoing hallucinations as well as thought, mood, current activity, social circumstances and places frequented. RESULTS: More subjects suffering from schizophrenia reported hallucinations, but for all hallucinating subjects the qualities of hallucination episodes were quite similar. More subjects reported visual hallucinations at least once. In contrast, the intensity of auditory hallucinations was higher. Anxiety was the most prominent emotion during hallucinations and reports of anxiety intensity exceeded baseline levels before the first report of auditory hallucinations. Context modified hallucination intensity over the course of an episode. Social withdrawal resulted in a decrease of hallucinatory intensity (AH > VH), while social engagement slightly raised intensity levels (VH > AH). Doing nothing (VH > AH) and work activities (AH > VH) led to decreases in intensity levels over time, while passive leisure activities (watching TV) resulted in increases in intensity levels of hallucinations (AH > VH). CONCLUSION: The results suggest that hallucinating experiences are subject to a host of contextual influences. Understanding variation offers useful insights for therapy.

Activities of Daily Living↗