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Biomedical subjects

Maarten Bak

Publications and source records attributed to Maarten Bak.

9 recordsLinked to original sources
PubMed2005

Hospital comorbidity bias and the concept of schizophrenia.

BACKGROUND: The comorbidity bias predicts that if disease definition is based on observations of patients in the hospital, spurious comorbidity of psychopathological dimensions that increase the probability of hospital admission will be included in the disease concept, whereas comorbid dimensions that are not associated with admission will be excluded. The direction of any dimensional comorbidity bias in psychotic illness was assessed in a longitudinal analysis of the psychopathology of patients assessed both inside and outside the hospital. METHOD: Four hundred and eighty patients with broadly defined psychotic disorders were assessed between one and nine times (median two times) over a 5-year period with, amongst others, the Brief Psychiatric Rating Scale. Dimensional comorbidities between positive symptoms, negative symptoms, depression/anxiety, and manic excitement were compared, in addition to their associations with current and future admission status. RESULTS: Higher levels of psychopathology in all symptom domains were associated with both current and future hospital admissions. Associations between the positive, negative, and manic symptom domains were higher for patients in the hospital than for patients outside the hospital, in particular, between positive symptoms and manic excitement (beta=0.28, p<0.001). However, associations between depression and other symptom domains were higher in out-patients as compared to in-patients (positive symptoms and depression, beta=-0.26; p<0.002). CONCLUSION: The current analyses suggest that, to the extent that disease concepts of psychosis do not take into account effects of dimensional comorbidity biases occasioned by differential psychopathology according to treatment setting, "florid" psychotic psychopathology may be overrepresented, whereas depressive symptoms may be spuriously excluded.

Adult↗
PubMed2005

Explaining transitions over the hypothesized psychosis continuum.

OBJECTIVES: It is crucial to understand the psychological mechanisms that mediate transition from having one or two psychotic symptoms to becoming a patient with a psychotic disorder. This study investigated whether: (i) a delusional interpretation and/or a depressed response to hallucinatory experiences predicts the later onset of clinical psychotic disorder; and (ii) the presence of need for care in relation to psychotic disorder was associated with the use of particular coping strategies. METHOD: A general population sample of 4672 individuals with no lifetime evidence of any psychotic disorder were interviewed with the Composite International Diagnostic Interview Schedule (CIDI) at baseline and 1 and 3 years later. At year 3, individuals with CIDI evidence of psychotic symptoms were interviewed by clinicians to identify onset of psychotic disorder with need for care. Coping, subjective distress with and perceived control over the psychotic experience were assessed using the Maastricht Assessment of Coping Strategies (MACS). RESULTS: Given the presence of hallucinatory experiences at baseline, the increase in risk on the additive scale of having the psychosis outcome at T2 was higher in the group with delusional ideation at T1 than in those without delusional ideation at T1. Similarly, presence of depressed mood at T1 increased the risk of having the psychosis outcome at T2, but this effect overlapped partly with the risk-increasing effect of delusional ideation. Individuals with a need for care were much more likely to display symptomatic coping, whereas the presence of the other coping types was not different across the groups with and without need for care. CONCLUSION: Transitions over the psychosis continuum are, at least in part, driven by the emotional, cognitive and behavioural responses to the initial psychotic or psychosis-like experiences. Individuals who react with a delusional interpretation, negative emotional states and/or a symptomatic coping style have an increased risk for developing clinical psychosis.

Adaptation, Psychological↗
PubMed2005

Development of depressed mood predicts onset of psychotic disorder in individuals who report hallucinatory experiences.

OBJECTIVES: Current psychological theories state that the clinical outcome of hallucinatory experiences is dependent on the degree of associated distress, anxiety, and depression. This study examined the hypothesis that the risk for onset of psychotic disorder in individuals with self-reported hallucinatory experiences would be higher in those who subsequently developed depressed mood than in those who did not. DESIGN: A prospective cohort study of a general population sample. METHODS: A sample of 4,670 individuals with no lifetime evidence of any psychotic disorder were interviewed with the Composite International Diagnostic Interview Schedule (CIDI) at baseline and 1 and 3 years later. At Year 3, individuals with CIDI evidence of psychotic symptoms were interviewed by clinicians to identify potential onset of psychotic disorder. Psychotic disorder was specified at three levels; two involving severity of positive symptoms of psychosis, and one using additional clinical judgment of need for care. RESULTS: Given the presence of hallucinatory experiences at baseline, the increase in risk of having the psychosis outcome at Year 3 was higher in the group with depressed mood at Year 1 than in the group without depressed mood at Year 1 (any level of psychotic symptoms: risk difference 17.0%, 95% CI - 1.7, 35.7; severe level of psychotic symptoms: risk difference 21.7%, 95% CI 3.2, 40.2; needs-based diagnosis of psychotic disorder: risk difference 16.8%, 95% CI 0.4, 33.3). CONCLUSION: The results are in line with current psychological models of psychosis that emphasize the role of secondary appraisals of psychotic experiences in the onset of clinical disorder.

Adult↗
PubMed2005

The incidence and outcome of subclinical psychotic experiences in the general population.

OBJECTIVES: To examine the incidence and 2-year stability and outcome of subclinical psychotic experiences in the general population. DESIGN: The Netherlands Mental Health Survey and Incidence Study (NEMESIS), a longitudinal general population study. METHODS: A representative population sample of 7,076 participants was interviewed with the composite international diagnostic interview at baseline, 1 year later at T(1) and again 2 years later at T(2). A sample of individuals was identified who had onset of a new, broadly defined psychotic experience between baseline and T(1) (N = 79; incidence = 2%). Stability and outcome of these incident positive psychotic experiences was reassessed by interview at T(2), at which 25 individuals had a CIDI rating of broadly defined psychotic experience (subclinical outcome) and 11 individuals had psychotic experiences with functional impairment and need for care (clinical outcome). RESULTS: The majority of individuals with an incident psychotic experience did not display persistence of the experience. Only 8% of individuals with a T1 incident psychotic experience had evidence of a T2 subclinical outcome, and only 8% had evidence of a T2 clinical outcome. The emotional context and the number of the T1 incident psychotic experiences were strong modifiers of predictive power for the clinical outcome, but not (or to a much lesser extent) for the subclinical outcome. CONCLUSIONS: The incidence of positive psychotic experiences in the general population is around 100 times greater than traditional estimates of incidence of psychotic disorder such as schizophrenia. The far most likely outcome for these experiences is discontinuity. For the small proportion who display continuity, there is an equally large likelihood of subclinical and clinical 2-year outcomes. Emotional appraisal and degree of intrusiveness of psychotic experiences are important modifiers not for continuity per se but for clinical outcome specifically.

Adolescent↗
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

Neuroticism and low self-esteem as risk factors for psychosis.

BACKGROUND: Low self-esteem and high neuroticism are common features in psychosis, but in the absence of longitudinal studies it is unclear whether they represent consequences of the illness or risk factors acting before illness onset. METHODS: A population sample of 3,929 individuals with no lifetime evidence of psychosis were interviewed with the Composite International Diagnostic Interview and were administered the Groningen Neuroticism Scale and the Rosenberg Self-Esteem Scale at baseline and 1 and 3 years later. At year 3, individuals with CIDI evidence of psychotic symptoms were interviewed by clinicians to identify incident psychotic or psychosis-like symptoms. RESULTS: Baseline neuroticism and self-esteem predicted first-ever onset of psychotic symptoms at year 3 (neuroticism, OR 1.16, 95% CI 1.09, 1.23; self-esteem, OR 1.09, 95% CI 1.01, 1.18).When adjusted for each other and for level of anxiety and depression, neuroticism was the strongest independent predictor for onset of psychotic symptoms (OR 1.16, 95% CI 1.07, 1.26). CONCLUSIONS: Neuroticism increases the risk for development of psychotic symptoms. Mechanisms of risk may involve certain cognitive styles associated with neuroticism, such as beliefs about the uncontrollability of certain events and experiences. The association between low self-esteem and psychosis may involve the area of overlap between self-esteem and neuroticism.

Adult↗
PubMedDate not supplied

Do different psychotic experiences differentially predict need for care in the general population?

INTRODUCTION: The pathway from subclinical psychotic experiences to need for care may depend on type of psychotic experience, level of associated distress, and previous experience of psychosis. METHOD: In a general population sample with no previous Diagnostic and Statistical Manual of Mental Disorders , Revised Third Edition , psychotic disorder (n = 4722), 83 subjects displayed at least one psychotic experience. Within the group of 83, subjects with (n = 24) and without need for care (n = 59) were compared. Presence of psychotic experiences at younger ages had been assessed at earlier interviews. RESULTS: Of 7 different psychotic experiences, only hearing voices, nonverbal hallucinations, and passivity phenomena were significantly associated with need for care. These associations were largely explained by the distress associated with the psychotic experience, but whether individuals had had psychotic experiences at earlier ages did not matter. CONCLUSIONS: Different psychotic experiences differ in the associated level of need for care and the mediating role of distress. Longer prior exposure to psychosis may not influence the pathway from subclinical to clinical.

Adolescent↗