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Dive into the research topics where Nynke Boonstra is active.

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Featured researches published by Nynke Boonstra.


Schizophrenia Research | 2014

Duration of untreated psychosis and negative symptoms ? A systematic review and meta-analysis of individual patient data

Nynke Boonstra; Rianne Klaassen; Sjoerd Sytema; Max Marshall; Lieuwe de Haan; L. Wunderink; Durk Wiersma

BACKGROUND Longer duration of untreated psychosis (DUP) is associated with poorer outcome in terms of positive symptoms, relapse rate, and time to remission. In contrast, the association with negative symptoms is less consistent. AIMS The study had three aims. First, to arrive at a more precise estimate of the correlation between DUP and negative symptoms than previous reviews, by substantially increasing the amount of available data. Second, to see whether the strength of this correlation attenuated over longer follow-up intervals. Third, to determine whether there is a relationship between DUP and changes in negative symptoms. METHOD Relevant databases were searched for studies published between December 1992 and March 2009 that reported data on DUP and negative symptoms. We obtained individual patient data where possible and calculated summary correlations between DUP and negative symptoms for each study at baseline, short and long-term follow-up. We used multilevel regression analysis to examine whether the effect of DUP on negative symptoms was the greatest in the early stages of illness. RESULTS We included 28 non-overlapping studies from the 402 papers detected by the search strategy. After contacting the authors we obtained individual patient data from 16 of these studies involving 3339 participants. The mean DUP was 61.4 weeks (SD=132.7, median DUP=12.0). Shorter DUP was significantly associated with less severe negative symptoms at baseline and also at short (1-2 years) and longer term follow-up (5-8 years) (r=0.117, 0.180 and 0.202 respectively, p<0.001). The relationship between improvement in negative symptoms and DUP was found to be non-linear: people with a DUP shorter than 9 months showed substantially greater negative symptom reduction than those with a DUP of greater than 9 months. CONCLUSIONS Shorter DUP is associated with less severe negative symptoms at short and long-term follow up, especially when the DUP is less than 9 months. Since there is no effective treatment for negative symptoms, reducing DUP to less than 9 months may be the best way to ameliorate them.


Acta Psychiatrica Scandinavica | 2008

Positive and useful auditory vocal hallucinations: prevalence, characteristics, attributions, and implications for treatment.

Ja Jenner; S. Rutten; J. Beuckens; Nynke Boonstra; Sjoerd Sytema

Objective:  Auditory hallucinations that are viewed by patients as positive and useful may be barriers to treatment‐seeking. The aim was to assess prevalence, impact, and course of, and attributions to, these voices in psychotic and non‐psychotic patients.


Journal of Medical Internet Research | 2013

A Web-Based Tool to Support Shared Decision Making for People With a Psychotic Disorder: Randomized Controlled Trial and Process Evaluation

Lian van der Krieke; Ando C. Emerencia; Nynke Boonstra; Lex Wunderink; Peter de Jonge; Sjoerd Sytema

Background Mental health policy makers encourage the development of electronic decision aids to increase patient participation in medical decision making. Evidence is needed to determine whether these decision aids are helpful in clinical practice and whether they lead to increased patient involvement and better outcomes. Objective This study reports the outcome of a randomized controlled trial and process evaluation of a Web-based intervention to facilitate shared decision making for people with psychotic disorders. Methods The study was carried out in a Dutch mental health institution. Patients were recruited from 2 outpatient teams for patients with psychosis (N=250). Patients in the intervention condition (n=124) were provided an account to access a Web-based information and decision tool aimed to support patients in acquiring an overview of their needs and appropriate treatment options provided by their mental health care organization. Patients were given the opportunity to use the Web-based tool either on their own (at their home computer or at a computer of the service) or with the support of an assistant. Patients in the control group received care as usual (n=126). Half of the patients in the sample were patients experiencing a first episode of psychosis; the other half were patients with a chronic psychosis. Primary outcome was patient-perceived involvement in medical decision making, measured with the Combined Outcome Measure for Risk Communication and Treatment Decision-making Effectiveness (COMRADE). Process evaluation consisted of questionnaire-based surveys, open interviews, and researcher observation. Results In all, 73 patients completed the follow-up measurement and were included in the final analysis (response rate 29.2%). More than one-third (48/124, 38.7%) of the patients who were provided access to the Web-based decision aid used it, and most used its full functionality. No differences were found between the intervention and control conditions on perceived involvement in medical decision making (COMRADE satisfaction with communication: F1,68=0.422, P=.52; COMRADE confidence in decision: F1,67=0.086, P=.77). In addition, results of the process evaluation suggest that the intervention did not optimally fit in with routine practice of the participating teams. Conclusions The development of electronic decision aids to facilitate shared medical decision making is encouraged and many people with a psychotic disorder can work with them. This holds for both first-episode patients and long-term care patients, although the latter group might need more assistance. However, results of this paper could not support the assumption that the use of electronic decision aids increases patient involvement in medical decision making. This may be because of weak implementation of the study protocol and a low response rate. Trial Registration Dutch Trial Register (NTR) trial number: 10340; http://www.trialregister.nl/trialreg/admin/rctsearch.asp?Term=10340 (Archived by WebCite at http://www.webcitation.org/6Jj5umAeS).


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

BACKGROUND Previously, 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. METHOD The 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. RESULTS The 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. CONCLUSIONS CBTuhr 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. TRIAL REGISTRATION The trial is registered at Current Controlled Trials as trial number ISRCTN21353122 (http://controlled-trials.com/ISRCTN21353122/gaag).


Clinical Practice & Epidemiology in Mental Health | 2008

Detection of psychosis by mental health care services; a naturalistic cohort study

Nynke Boonstra; L. Wunderink; Sjoerd Sytema; Durk Wiersma

BackgroundDetection of psychotic disorders is an important issue, since early treatment might improve prognosis. Timely diagnosis of psychotic disorders depends on recognition of psychotic symptoms and their interpretation. The aim of this study is to examine to what extent reported psychotic symptoms are accounted for in clinical diagnosis.MethodsThe medical files of all patients who had a first contact with one of two mental health care services (N = 6477) were screened for reported psychotic symptoms and subsequent clinical diagnosis. Patients who reported psychotic symptoms and who were diagnosed with a psychotic disorder were followed-up for two years to register prescription of antipsychotic treatment and continuity of care.ResultsIn the files of 242 (3.7%) patients specific psychotic symptoms were recorded. 37% of these patients were diagnosed with a non-affective psychotic disorder, 7% with other psychotic disorders and 56% with non-psychotic disorders or no diagnosis at all. About 90% of the patients diagnosed with a psychotic disorder did receive any prescription of antipsychotics, and about 50% were in continuous care during the first 2 years.ConclusionRelatively large proportions of patients presenting with psychotic symptoms were diagnosed with a non-psychotic diagnosis or not diagnosed at all. This applies also to patients reporting at least two or more psychotic symptoms. Although we did not verify the appropriateness of clinical diagnosis, these findings are an indication that psychotic disorders may be underdetected. Improving the diagnostic process in mental health care services may be the most obvious way to promote early intervention in psychosis.


Early Intervention in Psychiatry | 2009

Improving detection of first-episode psychosis by mental health-care services using a self-report questionnaire.

Nynke Boonstra; Lex Wunderink; Sjoerd Sytema; Durk Wiersma

Objective: To examine the utility of the Community Assessment of Psychic Experiences (CAPE)‐42, a self‐report questionnaire, to improve detection of first‐episode psychosis in new referrals to mental health services.


Psychiatry Research-neuroimaging | 2017

The effect of childhood adversity on 4-year outcome in individuals at ultra high risk for psychosis in the Dutch Early Detection Intervention Evaluation (EDIE-NL) Trial

Tamar Kraan; Helga K. Ising; Marjolein Fokkema; David P. G. van den Berg; Margot Kerkhoven; Wim Veling; Filip Smit; Don Linszen; Dorien H. Nieman; Lex Wunderink; Nynke Boonstra; Rianne Klaassen; Sara Dragt; Judith Rietdijk; Lieuwe de Haan; Mark van der Gaag

Childhood adversity is associated with a range of mental disorders, functional impairment and higher health care costs in adulthood. In this study we evaluated if childhood adversity was predictive of adverse clinical and functional outcomes and health care costs in a sample of patients at ultra-high risk (UHR) for developing a psychosis. Structural Equation Modeling was used to examine the effect of childhood adversity on depression, anxiety, transition to psychosis and overall functioning at 4-year follow-up. In addition, we evaluated economic costs of childhood adversity in terms of health care use and productivity loss. Data pertain to 105 UHR participants of the Dutch Early Detection and Intervention Evaluation (EDIE-NL). Physical abuse was associated with higher depression rates (b=0.381, p=0.012) and lower social functional outcome (b=-0.219, p=0.017) at 4-year follow-up. In addition, emotional neglect was negatively associated with social functioning (b=-0.313, p=0.018). We did not find evidence that childhood adversity was associated with transition to psychosis, but the experience of childhood adversity was associated with excess health care costs at follow-up. The data indicate long-term negative effects of childhood adversity on depression, social functioning and health care costs at follow-up in a sample of UHR patients.


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

Background This 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. Method The 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. Results The 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


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

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


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

24 560; €20 000 per QALY). Conclusions Add-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.

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Sjoerd Sytema

University Medical Center Groningen

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Durk Wiersma

University Medical Center Groningen

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L. Wunderink

University Medical Center Groningen

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Sara Dragt

University of Amsterdam

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Wim Veling

University Medical Center Groningen

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Filip Smit

VU University Amsterdam

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