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Dive into the research topics where Rianne M. C. Klaassen is active.

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Featured researches published by Rianne M. C. Klaassen.


Acta Psychiatrica Scandinavica | 2011

Three-year course of clinical symptomatology in young people at ultra high risk for transition to psychosis

D. H. Nieman; Rianne M. C. Klaassen; Hiske E. Becker; Peter Dingemans; D.H. Linszen; L. de Haan

Velthorst E, Nieman DH, Klaassen RMC, Becker HE, Dingemans PM, Linszen DH, de Haan L. Three year course of clinical symptomatology in young people at ultra high risk for transition to psychosis.


Psychological Medicine | 2015

Cost-effectiveness of preventing first-episode psychosis in ultra-high-risk subjects: multi-centre randomized controlled trial

Helga K. Ising; Filip Smit; Wim Veling; Judith Rietdijk; Sara Dragt; Rianne M. C. Klaassen; N. S. P. Savelsberg; Nynke Boonstra; Dorien H. Nieman; D.H. Linszen; L. Wunderink; M. van der Gaag

BACKGROUNDnAlthough there is evidence for the effectiveness of interventions for psychosis among ultra-high-risk (UHR) groups, health economic evaluations are lacking. This study aimed to determine the cost effectiveness and cost-utility of cognitive-behavioural therapy (CBT) to prevent first-episode psychosis.nnnMETHODnThe Dutch Early Detection and Intervention Evaluation study was a randomized controlled trial of 196 UHR patients with an 18-month follow-up. All participants were treated with routine care (RC) for non-psychotic disorders. The experimental group (nxa0=xa095) received add-on CBT to prevent first-episode psychosis. We report the intervention, medical and travel costs, as well as costs arising from loss of productivity. Treatment response was defined as psychosis-free survival and quality-adjusted life years (QALYs) gained.nnnRESULTSnIn the cost-effectiveness analysis, the proportion of averted psychoses was significantly higher in the CBT condition (89.5% v. 76.2%). CBT showed a 63.7% probability of being more cost effective, because it was less costly than RC by US


Schizophrenia Bulletin | 2016

Four-Year Follow-up of Cognitive Behavioral Therapy in Persons at Ultra-High Risk for Developing Psychosis : The Dutch Early Detection Intervention Evaluation (EDIE-NL) Trial

Helga K. Ising; Tamar Kraan; Judith Rietdijk; Sara Dragt; Rianne M. C. Klaassen; Nynke Boonstra; Dorien H. Nieman; Monique Willebrands-Mendrik; David P. G. van den Berg; Don Linszen; Lex Wunderink; Wim Veling; Filip Smit; Mark van der Gaag

844 (£551) per prevented psychosis. In the cost-utility analysis, QALY health gains were slightly higher for CBT than for RC (0.60 v. 0.57) and the CBT intervention had a 52.3% probability of being the superior treatment because, for equal or better QALY gains, the costs of CBT were lower than those of RC.nnnCONCLUSIONSnAdd-on preventive CBT for UHR resulted in a significant reduction in the incidence of first psychosis. QALY gains show little difference between the two conditions. The CBT intervention proved to be cost saving.


Psychological Medicine | 2012

Ethnicity and baseline symptomatology in patients with an At Risk Mental State for psychosis

D. H. Nieman; Wim Veling; Rianne M. C. Klaassen; Sara Dragt; Judith Rietdijk; Helga K. Ising; L. Wunderink; D.H. Linszen; L. de Haan; M. van der Gaag

BACKGROUNDnPreviously, we demonstrated that cognitive behavior therapy for ultra-high risk (called CBTuhr) halved the incidence of psychosis over an 18-month period. Follow-up data from the same study are used to evaluate the longer-term effects at 4 years post-baseline.nnnMETHODnThe Dutch Early Detection and Intervention Evaluation study was a randomized controlled trial of 196 UHR patients comparing CBTuhr with treatment-as-usual (TAU) for comorbid disorders with TAU only. Of the original 196 patients, 113 consented to a 4-year follow-up (57.7%; CBTuhr = 56 vs TAU = 57). Over the study period, psychosis incidence, remission from UHR status, and the effects of transition to psychosis were evaluated.nnnRESULTSnThe number of participants in the CBTuhr group making the transition to psychosis increased from 10 at 18-month follow-up to 12 at 4-year follow-up whereas it did not change in the TAU group (n = 22); this still represents a clinically important (incidence rate ratio [IRR] = 12/22 = 0.55) and significant effect (F(1,5) = 8.09, P = .03), favoring CBTuhr. The odds ratio of CBTuhr compared to TAU was 0.44 (95% CI: 0.24-0.82) and the number needed to treat was 8. Moreover, significantly more patients remitted from their UHR status in the CBTuhr group (76.3%) compared with the TAU group (58.7%) [t(120) = 2.08, P = .04]. Importantly, transition to psychosis was associated with more severe psychopathology and social functioning at 4-year follow-up.nnnCONCLUSIONSnCBTuhr to prevent a first episode of psychosis in persons at UHR of developing psychosis is still effective at 4-year follow-up. Our data also show that individuals meeting the formal criteria of a psychotic disorder have worse functional and social outcomes compared with non-transitioned cases.nnnTRIAL REGISTRATIONnThe trial is registered at Current Controlled Trials as trial number ISRCTN21353122 (http://controlled-trials.com/ISRCTN21353122/gaag).


Schizophrenia Bulletin | 2016

Four-Year Cost-effectiveness of Cognitive Behavior Therapy for Preventing First-episode Psychosis: The Dutch Early Detection Intervention Evaluation (EDIE-NL) Trial

Helga K. Ising; Joran Lokkerbol; Judith Rietdijk; Sara Dragt; Rianne M. C. Klaassen; Tamar Kraan; Nynke Boonstra; Dorien H. Nieman; David P. G. van den Berg; Don Linszen; Lex Wunderink; Wim Veling; Filip Smit; Mark van der Gaag

BACKGROUNDnEthnicity has been associated with different incidence rates and different symptom profiles in young patients with psychotic-like disorders. No studies so far have examined the effect of ethnicity on symptoms in people with an At Risk Mental State (ARMS).nnnMETHODnIn this cross-sectional study, we analysed the relationship between ethnicity and baseline data on the severity of psychopathology scores in 201 help-seeking patients who met the ARMS criteria and agreed to participate in the Dutch Early Detection and Intervention (EDIE-NL) trial. Eighty-seven of these patients had a non-Dutch ethnicity. We explored the possible mediating role of ethnic identity.nnnRESULTSnHigher rates of negative symptoms, and of anhedonia in particular, were found in the ethnic minority group. This result could be attributed mainly to the Moroccan-Dutch and Turkish-Dutch subgroups, who also presented with more depression symptoms when the groups were examined separately. The ethnic minority group displayed a lower level of ethnic group identity compared to the immigrants of the International Comparative Study of Ethnocultural Youth (ICSEY). Ethnic identity was inversely related to symptoms in the Moroccan-Dutch patient group.nnnCONCLUSIONSnThe prevalence of more severe negative symptoms and depression symptoms in ethnic minority groups deserves more attention, as the experience of attenuated positive symptoms when accompanied by negative symptoms or distress has proven to be predictive for transition to a first psychotic episode.


Psychological Medicine | 2016

Development of a stage-dependent prognostic model to predict psychosis in ultra-high-risk patients seeking treatment for co-morbid psychiatric disorders

Helga K. Ising; S. Ruhrmann; Nadine A. F. M. Burger; Judith Rietdijk; Sara Dragt; Rianne M. C. Klaassen; D.P.G. van den Berg; Dorien H. Nieman; Nynke Boonstra; D.H. Linszen; L. Wunderink; Filip Smit; Wim Veling; M. van der Gaag

BackgroundnThis study aims to evaluate the long-term cost-effectiveness of add-on cognitive behavior therapy (CBT) for the prevention of psychosis for individuals at ultrahigh risk (UHR) of psychosis.nnnMethodnThe Dutch Early Detection and Intervention randomized controlled trial was used, comparing routine care (RC; n = 101) with routine care plus CBT for UHR (here called CBTuhr; n = 95). A cost-effectiveness analysis was conducted with treatment response (defined as proportion of averted transitions to psychosis) as an outcome and a cost-utility analysis with quality-adjusted life years (QALYs) gained as a secondary outcome.nnnResultsnThe proportion of averted transitions to psychosis was significantly higher in the CBTuhr condition (with a risk difference of 0.122; b = 1.324, SEb = 0.017, z = 7.99, P < 0.001). CBTuhr showed an 83% probability of being more effective and less costly than RC by -US


BMC Psychiatry | 2014

Psychometric properties of the self-report version of the Quick Inventory of Depressive Symptoms (QIDS-SR16) questionnaire in patients with schizophrenia

Irene M. Lako; Johanna T. W. Wigman; Rianne M. C. Klaassen; Cees J. Slooff; Katja Taxis; Agna A. Bartels-Velthuis

5777 (savings) per participant. In addition, over the 4-year follow-up period, cumulative QALY health gains were marginally (but not significantly) higher in CBTuhr than for RC (2.63 vs. 2.46) and the CBTuhr intervention had a 75% probability of being the superior treatment (more QALY gains at lower costs) and a 92% probability of being cost-effective compared with RC at the Dutch threshold value (US


International Journal of Methods in Psychiatric Research | 2017

The Prodromal Questionnaire: A case for IRT-based adaptive testing of psychotic experiences?

Jan van Bebber; Johanna T. W. Wigman; Rob R. Meijer; Helga K. Ising; David Van Den Berg; Judith Rietdijk; Sara Dragt; Rianne M. C. Klaassen; Dorien H. Nieman; Peter de Jonge; Sjoerd Sytema; Marieke Wichers; Don Linszen; Mark van der Gaag; Lex Wunderink

24 560; €20 000 per QALY).nnnConclusionsnAdd-on preventive CBTuhr had a high likelihood (83%) of resulting in more averted transitions to psychosis and lower costs as compared with RC. In addition, the intervention had a high likelihood (75%) of resulting in more QALY gains and lower costs as compared to RC.


European Psychiatry | 2011

S21-01 - Predictors of persistence of ultrahigh risk symptoms and predictors of transition into psychosis

M. van der Gaag; Judith Rietdijk; Helga K. Ising; Sara Dragt; Rianne M. C. Klaassen; D. H. Nieman; L. Wunderink; D.H. Linszen

BACKGROUNDnCurrent ultra-high-risk (UHR) criteria appear insufficient to predict imminent onset of first-episode psychosis, as a meta-analysis showed that about 20% of patients have a psychotic outcome after 2 years. Therefore, we aimed to develop a stage-dependent predictive model in UHR individuals who were seeking help for co-morbid disorders.nnnMETHODnBaseline data on symptomatology, and environmental and psychological factors of 185 UHR patients (aged 14-35 years) participating in the Dutch Early Detection and Intervention Evaluation study were analysed with Cox proportional hazard analyses.nnnRESULTSnAt 18 months, the overall transition rate was 17.3%. The final predictor model included five variables: observed blunted affect [hazard ratio (HR) 3.39, 95% confidence interval (CI) 1.56-7.35, p < 0.001], subjective complaints of impaired motor function (HR 5.88, 95% CI 1.21-6.10, p = 0.02), beliefs about social marginalization (HR 2.76, 95% CI 1.14-6.72, p = 0.03), decline in social functioning (HR 1.10, 95% CI 1.01-1.17, p = 0.03), and distress associated with suspiciousness (HR 1.02, 95% CI 1.00-1.03, p = 0.01). The positive predictive value of the model was 80.0%. The resulting prognostic index stratified the general risk into three risk classes with significantly different survival curves. In the highest risk class, transition to psychosis emerged on average ⩾8 months earlier than in the lowest risk class.nnnCONCLUSIONSnPredicting a first-episode psychosis in help-seeking UHR patients was improved using a stage-dependent prognostic model including negative psychotic symptoms (observed flattened affect, subjective impaired motor functioning), impaired social functioning and distress associated with suspiciousness. Treatment intensity may be stratified and personalized using the risk stratification.


Tijdschrift voor psychiatrie | 2012

Psychotic disorders: The need for staging

Lieuwe de Haan; Rianne M. C. Klaassen; L. Van Beveren; Lex Wunderink; Bart Rutten; Jim van Os

BackgroundSelf-report instruments for the assessment of depressive symptoms in patients with psychotic disorders are scarce. The Quick Inventory of Depressive Symptoms (QIDS-SR16) may be a useful self-report instrument, but has received little attention in this field. This paper aimed to test the psychometric properties of the QIDS-SR16 questionnaire in patients with a psychotic disorder.MethodsPatients diagnosed with a psychotic disorder from health care institutions in The Netherlands were included in the study. Depressive symptoms were assessed with the QIDS-SR16 and the Calgary Depression Scale for Schizophrenia (CDSS). Psychotic symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS) and extrapyramidal symptoms (EPS) with three EPS rating scales. Spearman’s correlation coefficients were used to compare the total score of the QIDS-SR16 with the total scores of the CDSS, PANSS-subscales and EPS rating scales.ResultsIn a sample of 621 patients with psychotic disorders, the QIDS-SR16 showed good internal consistency (α = 0.87). The QIDS-SR16 correlated moderately with the CDSS (r = 0.44) and the PANSS subscale for emotional distress (r = 0.47). The QIDS-SR16 showed weak correlation with the PANSS subscale for negative symptoms (r = 0.28) and minimal correlation with EPS rating scales (r = 0.09-0.16).ConclusionsThe QIDS-SR16 may reliably assess depressive symptoms in patients with psychotic disorders, but its concurrent validity with the CDSS was rather poor in this population. We would recommend developing a new self-report questionnaire for the assessment of depressive symptoms in patients with psychotic disorders.

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Sara Dragt

University of Amsterdam

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D.H. Linszen

University of Amsterdam

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Nynke Boonstra

University Medical Center Groningen

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L. Wunderink

University Medical Center Groningen

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Wim Veling

University Medical Center Groningen

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D. H. Nieman

Academic Medical Center

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Don Linszen

University of Amsterdam

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