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Biomedical subjects

J van Os

Publications and source records attributed to J van Os.

At least 55 records · Page 3Linked to original sources
PubMed2003

Suicide and attempted suicide among people of Caribbean origin with psychosis living in the UK.

BACKGROUND: A report from a 1980s cohort claimed that suicidal behaviour was four times less common in UK-resident people of Caribbean origin with psychosis than in British Whites. Since then, evidence has accumulated that the rate of suicide and suicidal ideation has been increasing. Aims To compare rates of suicidal behaviour in people of Caribbean and British White origin in a large multi-centre sample of patients with psychosis. METHOD: A secondary analysis of 708 patients with psychosis followed up for 2 years. Outcome measures of reported suicide and attempted suicide were adjusted for socio-economic and clinical differences between groups at baseline. RESULTS: People of Caribbean origin had a lower risk of suicidal behaviour than British Whites (odds ratio adjusted for age and gender 0.49, 95% CI 0.26-0.92). There was a strong negative interaction between ethnic group and age: suicidal acts were four times less likely in people of Caribbean origin aged over 35 years compared with British Whites, but there was no large or significant difference in those under 35. CONCLUSIONS: The previously reported lower relative risk of suicidal behaviour in people of Caribbean origin with psychosis is restricted to those over 35 years, suggesting that the protective effect of Caribbean origin is disappearing in younger generations.

Adult↗
PubMed2002

Cannabis use and psychosis: a longitudinal population-based study.

Cannabis use may increase the risk of psychotic disorders and result in a poor prognosis for those with an established vulnerability to psychosis. A 3-year follow-up (1997-1999) is reported of a general population of 4,045 psychosis-free persons and of 59 subjects in the Netherlands with a baseline diagnosis of psychotic disorder. Substance use was assessed at baseline, 1-year follow-up, and 3-year follow-up. Baseline cannabis use predicted the presence at follow-up of any level of psychotic symptoms (adjusted odds ratio (OR) = 2.76, 95% confidence interval (CI): 1.18, 6.47), as well as a severe level of psychotic symptoms (OR = 24.17, 95% CI: 5.44, 107.46), and clinician assessment of the need for care for psychotic symptoms (OR = 12.01, 95% CI: 2.24, 64.34). The effect of baseline cannabis use was stronger than the effect at 1-year and 3-year follow-up, and more than 50% of the psychosis diagnoses could be attributed to cannabis use. On the additive scale, the effect of cannabis use was much stronger in those with a baseline diagnosis of psychotic disorder (risk difference, 54.7%) than in those without (risk difference, 2.2%; p for interaction = 0.001). Results confirm previous suggestions that cannabis use increases the risk of both the incidence of psychosis in psychosis-free persons and a poor prognosis for those with an established vulnerability to psychotic disorder.

Adolescent↗
PubMed2002

2-COM: an instrument to facilitate patient-professional communication in routine clinical practice.

OBJECTIVE: A simple patient-completed self-report instrument may facilitate patient-professional carer communication. METHOD: A 19-item self-report needs schedule was used in a sample of 243 out-patients with non-affective psychosis. Patients and professional carers commented on the usefulness of the instrument. In a subgroup of 95 patient-carer dyads, the professional carer was asked to rate the needs in addition to the patient. RESULTS: Patients scored their needs reliably and lower than the professionals (OR = 0.9, 95% CI: 0.9, 0.97). Concordance between patients and professional carers on individual needs was very low. More than 50% of the professional carers and more than 80% of the patients found 2-COM useful. The higher the number of needs indicated by the patient, the greater the discrepancy between patients and professional carers with regard to the usefulness of the schedule. CONCLUSION: 2-COM is a useful instrument to expose, and subsequently bridge, patient-professional carer discordance on patient needs.

Adult↗
PubMed2002

Child psychopathology and lower cognitive ability: a general population twin study of the causes of association.

Previous work has demonstrated associations between lower cognitive ability and childhood and adult non-psychotic psychopathology. As both cognitive ability (CA) and child psychopathology (CP) are influenced by genetic factors, one explanation for the association is that they are the pleiotropic manifestations of the same underlying genetic factors. The present paper examines three possible causes of the association: additive genetic factors, common environmental factors and individual-specific environmental factors. Three hundred and seventy-six twin pairs from the East Flanders Prospective Twin Survey were examined with the Child Behaviour Checklist and the Wechsler Intelligence Scale for Children-Revised. The cross-twin within-variable, within-twin cross-variable and cross-twin cross-variable correlations were calculated. Using structural equation modelling, bivariate models were fitted. The best fitting model was chosen, based on likelihood and parsimony. The observed phenotypic correlation between CP and CA was -0.19 (95% CI: -0.09, -0.27), with genetic factors accounting for about 84% of the observed correlation. Bivariate model fitting quantified the genetic correlation between CP and CA at -0.27 (95% CI: -0.12, -0.42) and the individual-specific environmental correlation at -0.17 (95% CI: -0.03, -0.31). In children, three different genetic factors may exist: one that solely affects the liability to CP, one that has only an effect on CA and one that influences both CP and CA. While individual-specific environmental factors can influence the liability to both traits, our results suggest that most of the environmental factors that increase the risk of CP do not influence CA and vice versa.

Adolescent↗
PubMed2001

Incidence of schizophrenia in ethnic minorities in London: ecological study into interactions with environment.

OBJECTIVE: To determine whether the incidence of schizophrenia among people from non-white ethnic minorities is greater in neighbourhoods where they constitute a smaller proportion of the total population. DESIGN: Ecological design including retrospective study of case records to calculate the incidence of schizophrenia in the ethnic minority population across electoral wards and multi-level analysis to examine interaction between individuals and environment. SETTING: 15 electoral wards in Camberwell, South London. PARTICIPANTS: All people aged 16 years and over who had contact with psychiatric services during 1988-97. MAIN OUTCOME MEASURE: Incidence rates of schizophrenia according to Research Diagnostic Criteria. RESULTS: The incidence of schizophrenia in non-white ethnic minorities increased significantly as the proportion of such minorities in the local population fell. The incidence rate ratio varied in a dose-response fashion from 2.38 (95% confidence interval 1.49 to 3.79) in the third of wards where non-white ethnic minorities formed the largest proportion (28-57%) of the local population to 4.4 (2.49 to 7.75) in the third of wards where they formed the smallest proportion (8-22%). CONCLUSION: The incidence of schizophrenia in non-white ethnic minorities in London is greater when they comprise a smaller proportion of the local population.

Ethnicity↗
PubMed2001

A prospective twin study of birth weight discordance and child problem behavior.

BACKGROUND: We investigated whether low birth weight constitutes a causal risk factor for child problem behavior, using a variation of the co-twin control method. METHODS: In a representative sample of 745 twin pairs (monozygotic: 324 pairs), birth weight was recorded at birth and child problem behavior at mean age 10 years was measured with the Child Behaviour Checklist (CBCL). RESULTS: Lower birth weight was a continuous risk factor for later child problem behavior (adjusted regression coefficient over units of 500 g: beta = -.15, p =.046), and greater levels of within-pair CBCL discordance did not result in a reduced effect size. Greater within-pair birth weight discordance was associated with greater within-pair CBCL score discordance (beta =.35, p <.001). This latter effect was similar in monozygotic (beta =.34, p =.005) and dizygotic twins (beta =.37, p =.003). CONCLUSIONS: The fact that (1) the effect size of the association between low birth weight and child problem behavior was not reduced in pairs with greater levels of CBCL discordance, and (2) similar effect sizes were found in monozygotic and dizygotic twins for the within-pair association between birth weight discordance and CBCL score discordance, suggests that the observed relationship between low birth weight and child problem behavior is not due to a shared environmental or genetic variable that influences both characteristics. Lower birth weight is a causal risk factor for child problem behavior, the effects of which may well extend into adulthood.

Adolescent↗
PubMed2001

Is the association between duration of untreated psychosis and outcome confounded? A two year follow-up study of first-admitted patients.

OBJECTIVE: To assess whether a long duration of untreated psychosis (DUP) before first admission predicts poor clinical and social outcome, and whether this association, if any, is confounded by premorbid and clinical characteristics. METHOD: A population-based sample of first-admitted subjects with psychosis (n = 65) was assessed at six monthly intervals over a two year follow-up using multiple sources of information. RESULTS: Most subjects (87%) with a life-chart 'continuous' course of psychotic symptoms had a history of a 'long' delay between onset of psychotic symptoms and first admission (> or = 3 months, median split), compared with 55% of subjects with a course of 'neither episodic nor continuous', 42% of subjects with an 'episodic' course, and 33% of subjects with 'no psychotic symptoms' during the follow-up period (RR = 9; 95%CI 1.5-54.8, P = 0.02). The strength of association between DUP and continuous course of psychosis was strongly reduced (63%) after adjustment for premorbid functioning, and to a lesser extent for the severity of illness and for the intensity of negative symptoms at first admission. CONCLUSIONS: The association between DUP and poor outcome may be spurious, confounded by the fact that poor premorbid functioning is independently associated with both DUP and poor outcome, with no direct causal link between these two latter variables. DUP may also be on the causal pathway between poor premorbid functioning and poor outcome, poor adjustment delaying access to care, and subsequently increasing the risk of presenting with a non-remitting course of illness. The links between premorbid functioning, DUP and outcome have to be further explored to clarify the directions of the associations between these variables.

Adolescent↗
PubMed2001

Single or multiple familial cognitive risk factors in schizophrenia?

The fact that relatives of patients with schizophrenia display subtle cognitive abnormalities suggests genetic transmission of an underlying cognitive endophenotype. It was examined to what extent the cognitive abnormalities that discriminate patients and relatives from controls do so independently of each other, and independent of IQ. Neuropsychological measures were assessed in 50 patients with schizophrenia, 50 first-degree relatives of patients with schizophrenia, and 50 healthy controls. The assessment focused on episodic memory, attentional span, simple and complex speed of information, and semantic memory. Factor analysis of the cognitive test results yielded four factors reflecting speed, episodic memory, working memory, and semantic fluency. Performance of the relatives was intermediate to that of the patients and the controls after adjustment for age, sex, educational level, and IQ. For both patients and relatives, speed of information processing, working memory, and episodic memory independently discriminated from control performance, with a similar pattern in the order of the size of the effects. The results suggest the existence of more than one familial cognitive risk factor for schizophrenia. Independent familial cognitive risk factors may represent separate causal influences or separate indicators of risk related to the same genetic mechanism.

Adult↗
PubMed2001

Emotional reactivity to daily life stress in psychosis.

BACKGROUND: The vulnerability-stress model of psychotic disorders describes, in essence, an interaction between personal vulnerability and environmental stressors. The present study investigated this interaction and studied emotional reactivity to daily life stress as a vulnerability marker for psychotic illness. METHODS: Patients with psychotic illness (n = 42), their first-degree relatives (n = 47), and control subjects (n = 49) were studied with the Experience Sampling Method (a structured diary technique assessing thoughts, current context, and mood in daily life) to assess (1) appraised subjective stress of daily events and smaller disturbances in daily life and (2) emotional reactivity conceptualized as changes in both negative affect and positive affect. RESULTS: Multilevel regression analyses showed that an increase in subjective stress was associated with an increase in negative affect and a decrease in positive affect in all groups. However, the groups differed quantitatively in their pattern of reactions to stress. Patients with psychotic illness reacted with more intense emotions to subjective appraisals of stress in daily life than control subjects. The decrease in positive affect in the relatives was similar to that of the patients, while the increase in negative affect in this group was intermediary to that of patients and control subjects. CONCLUSIONS: Higher levels of familial risk for psychosis were associated with higher levels of emotional reactivity to daily life stress in a dose-response fashion. Subtle alterations in the way persons interact with their environment may constitute part of the vulnerability for psychotic illness.

Adaptation, Psychological↗
PubMed2001

Prevalence of psychotic disorder and community level of psychotic symptoms: an urban-rural comparison.

BACKGROUND: Urban and rural populations have different rates of psychotic illness. If psychosis exists as a continuous phenotype in nature, urban-rural population differences in the rate of psychotic disorder should be accompanied by similar differences in the rate of abnormal mental states characterized by psychotic or psychosislike symptoms. METHODS: A random sample of 7076 individuals aged 18 to 64 years were interviewed by trained lay interviewers with the Composite International Diagnostic Interview. Approximately half of those with evidence of psychosis according to the Composite International Diagnostic Interview were additionally interviewed by clinicians. We investigated associations between a 5-level urbanicity rating and (1) any DSM-III-R diagnosis of psychotic disorder (sample prevalence, 1.5%), (2) any rating of hallucinations and/or delusions (sample prevalence, 4.2%), and (3) any rating of psychotic or psychosislike symptoms (sample prevalence, 17.5%). RESULTS: Level of urbanicity was associated not only with DSM-III-R psychotic disorder (adjusted odds ratio [OR] over 5 levels, 1.47; 95% confidence interval [CI], 1.25-1.72), but also, independently, with any rating of delusion and/or hallucination (adjusted OR, 1.28; 95% CI, 1.17-1.40; clinician-assessed psychotic symptoms only: OR, 1.30; 95% CI, 1.03-1.64) and any rating of psychosislike symptom (adjusted OR, 1.18; 95% CI, 1.13-1.24). Psychotic symptoms were strongly and independently associated with psychotic disorder, regardless of the level of urbanization. CONCLUSIONS: Community level of psychotic and psychosislike symptoms may be inextricably linked to the prevalence of psychotic disorder. The prevalence of abnormal mental states that facilitate development to overt psychotic illness increases progressively with level of urbanization.

Adolescent↗
PubMed2001

Associations between nonshared environment and child problem behaviour.

BACKGROUND: Twin studies suggest that environmental effects on the development of child psychopathology largely involve nonshared environmental processes. However, the influence of the nonshared environment may have been overestimated, as the relationship between environment and behaviour may be genetically mediated. A direct measure of the nonshared environment (using the Sibling Inventory of Differential Experience - SIDE) was investigated in relation to child psychopathology, and tested for possible genetic mediation. METHOD: Parent-rated versions of the Child Behaviour Checklist (CBCL) and the SIDE were collected in 760 twin pairs aged 6-17 years. Multilevel regression analysis was used to assess the influence of SIDE scores on CBCL total problem scores, internalising symptoms, externalising symptoms and depressive symptom scores. Genetic mediation was assessed by examining interaction with zygosity in the association between SIDE scores and differences in CBCL scores (absence of interaction indicating no genetic mediation). RESULTS: The results revealed significant associations between SIDE dimensions on the one hand, and degree of internalising, externalising, depression and total symptom scores on the other. However, the effects were non-linear, and especially apparent for the extremes of differential environmental experience within twin pairs. Overall, there was no strong evidence for genetic mediation of associations between nonshared environment and symptoms. CONCLUSIONS: Direct, genetically unconfounded but skewed relationships may exist between nonshared environment on the one hand and behavioural differences on the other, although longitudinal data are necessary to determine the direction of effects.

Adolescent↗
PubMed2001

Does socioeconomic status predict course and outcome in patients with psychosis?

BACKGROUND: We examined the relationship between socioeconomic status (SES) and course and outcome of patients with psychosis. Two hypotheses were examined: a) patients with higher best-ever SES will have better course and outcome than those with lower best-ever SES, and b) patients with greater downward drift in SES will have poorer course and outcome than those with less downward drift. METHOD: Data were drawn from the baseline and 2-year follow-up assessments of the UK700 Case Management Trial of 708 patients with severe psychosis. The indicators of SES used were occupational status and educational achievement. Drift in SES was defined as change from best-ever occupation to occupation at baseline. RESULTS: For the baseline data highly significant differences were found between best-ever groups and negative symptoms (non-manual vs. unemployed--coef -10.5, p=0.000, 95% CIs 5.1-15.8), functioning (non-manual vs. unemployed--coef -0.6, p=0.000, 95% CIs 0.3 to -0.8) and unmet needs (manual vs. unemployed - coef 0.5, p=0.004, 95% CIs 0.2-0.9). No significant differences between best-ever groups were found for days in hospital, symptoms, perceived quality of life and dissatisfaction with services. Significant differences for clinical and social variables were found between drift and non-drift SES groups. There were no significant findings between educational groups and clinical and social variables. CONCLUSIONS: Best-ever occupation, but not educational qualifications, appeared to predict prognosis in patients with severe psychosis. Downward drift in occupational status did not result in poorer illness course and outcome.

Adult↗
PubMed2001

Stroke and mental health care: a record linkage study.

BACKGROUND: Stroke is associated with psychiatric morbidity but little is known about mental health care use in stroke patients. METHOD: A probability record linkage study was conducted linking stroke cases admitted to a teaching hospital serving a catchment area between 1987 and 1995 with records from a psychiatric case register covering the same area. RESULTS: Stroke patients had a more than twofold increased risk of contact with mental health care than individuals in the general population (yearly prevalences of respectively 88 and 39 per 1000; risk ratio 2.24; 95 % CI 2.04-2.45). One-third of all stroke admissions had had mental health care before and more than half had had mental health care after the stroke. In the year of admission for stroke, the probability of receiving mental health care was highest, while in the more remote years the risk was lower. CONCLUSION: Stroke is associated with an increased probability of contact with mental health services. The pattern of mental health care of a stroke patient is different from that of other mental health patients: more episodic and concentrated around the time of admission for stroke.

Adult↗
PubMed2001

The continuity of psychotic experiences in the general population.

Schizophrenia is a severe mental illness that affects 1% of the population. The diagnosis is made according to current diagnostic systems of DSM-IV (American Psychiatric Association, 1994) and ICD-10 (World Health Association, 1992) on the basis of characteristic 'positive' and 'negative' symptoms. The traditional medical model assumes a categorical view of the schizophrenia syndrome and its core symptoms, in which differences between psychotic symptoms and their normal counterparts are considered to be qualitative. An alternative, dimensional approach assumes that schizophrenia is not a discrete illness entity, but that psychotic symptoms differ in quantitative ways from normal experiences and behaviours. This paper reviews evidence for the continuity of psychotic symptoms with normal experiences, focusing on the symptoms of hallucinations and delusions. It concludes by discussing the theoretical and treatment implications of such a continuum.

Delusions↗
PubMed2001

Neuropsychological performance of psychotic patients in community care: results from the UK700 study.

OBJECTIVE: To compare cognitive performance in chronic schizophrenic and affective psychotic patients maintained in community care. METHOD: We studied a sample of community-based patients (n = 707) with chronic psychotic disorders. Neuropsychological assessment was completed using the National Adult Reading Test (NART) and the Trail Making Test (TMT). RESULTS: Affective psychotic patients had higher premorbid IQ than schizophrenic patients before adjustment for confounding factors (P=0.03); however, after adjustment for ethnic group and social class this became non-significant (P=0.19). There were no significant differences between groups on the TMT, parts A or B. CONCLUSION: Unlike studies suggesting that schizophrenic patients are more cognitively impaired than affective psychotic patients, our study suggests a degree of cognitive homogeneity between those patients who develop a chronic illness. Measures of premorbid IQ suggest that this cognitive homogeneity exists prior to the onset of illness.

Adult↗
PubMed2001

Predictors and outcome characteristics associated with suicidal behaviour in early psychosis: a two-year follow-up of first-admitted subjects.

OBJECTIVE: To assess the baseline characteristics associated with a greater risk of suicidal behaviour (suicide and parasuicide) over the 2 years following a first admission for psychosis, and the associations between suicidality and outcome. METHOD: First-admitted subjects with psychosis (n=65) were assessed at 6-monthly intervals over a 2-year follow-up period. RESULTS: Over this period, 11.3% of the patients displayed suicidal behaviour. Baseline predictors of suicidal behaviour were a lifetime history of parasuicide before first admission (OR=5.9, 95% CI 1.5-23.4), lower Positive And Negative Symptom Scale positive subscores (OR=0.8, 95% CI 0.6-0.97) and a longer duration of first admission (OR=1.1, 95% CI 1-1.2). Subjects with suicidal behaviour presented with a longer duration of psychotic symptoms (OR=1.1, 95% CI 1.02-1.2) and a greater risk of being readmitted (OR=4.6, 95%CI 1.1-19.1). Subjects with substance misuse over the follow-up period were seven times (95%CI 1.3-39) more likely to engage in suicidal behaviour. CONCLUSION: Subjects with a previous history of parasuicide, with a deteriorating clinical course, or with substance misuse are at increased risk of suicidal behaviour in the 2 years after the onset of a first psychotic episode.

Adult↗