Herman Ader

Herman Ader
Independent Researcher

PhD Social science methodology

About

201
Publications
69,045
Reads
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14,032
Citations
Additional affiliations
November 2003 - present
University of Amsterdam
Position
  • Guest lecturer
Description
  • Each year in the Fall, I give a course `Methodological Advice' in cooperation with Prof dr G. J. Mellenbergh. The course is attended by research master students.
May 1993 - May 2005
Amsterdam University Medical Center
Position
  • Professor (Assistant)
Description
  • I gave advise on Statistical Applications and research methods.

Publications

Publications (201)
Article
Objective: To examine if chest pain increases the risk of depression and anxiety, or, on the other hand, depression and anxiety increase the risk of chest pain onset in patients with coronary heart disease (CHD). Design: Prospective clinical study. Setting: 16 general practices in the Greater London Primary Care Research Network. Participants...
Chapter
We examined how effectively multimedia applications (computer-assisted instruction, e-books, and TV/Video) benefit the literacy development of at-risk and not-at-risk children. Blok et al. (Rev Educ Res 72:101–130, 2002) analysed computer-assisted instruction studies undertaken in the 1990–2000 period and found an effect size of 0.254. Due to impro...
Article
Objective : Generalized anxiety and panic disorder are a burden on society because they are costly and have a significant adverse effect on quality of life. The aim of this study was to evaluate the cost-utility of a collaborative stepped care intervention for panic disorder and generalized anxiety disorder in primary care compared to care as usual...
Article
Full-text available
The present study reports on the construction of a research instrument developed to examine preschool teachers’ beliefs and practices in relation to emergent literacy. A 130-item survey (Preschool Literacy Survey, PLS) was completed by a total of 90 preschool teachers in Norway. Items were grouped into homogenous scales, and the relationship betwee...
Article
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Background: Collaborative stepped care (CSC) may be an appropriate model to provide evidence-based treatment for anxiety disorders in primary care. Methods: In a cluster randomised controlled trial, the effectiveness of CSC compared to care as usual (CAU) for adults with panic disorder (PD) or generalised anxiety disorder (GAD) in primary care w...
Article
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Questionnaires may help in detecting and diagnosing anxiety disorders in primary care. However, since utility of these questionnaires in target populations is rarely studied, the Patient Health Questionnaire anxiety modules (PHQ) were evaluated for use as: a) a screener in high-risk patients, and/or b) a case finder for general practitioners (GPs)...
Article
Full-text available
BACKGROUND: Questionnaires may help in detecting and diagnosing anxiety disorders in primary care. However, since utility of these questionnaires in target populations is rarely studied, the Patient Health Questionnaire anxiety modules (PHQ) were evaluated for use as: a) a screener in high-risk patients, and/or b) a case finder for general practiti...
Article
Objectives Major depressive disorder (MDD) is associated with absenteeism. In this study, the effectiveness of collaborative care, with a focus on return to work (RTW), was evaluated in its effect on depressive symptoms and the duration until RTW in sick-listed workers with MDD in the occupational health setting. Methods In this randomised controll...
Article
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BACKGROUND: Practice variation in the primary care treatment of depression may be considerable in the Netherlands, due to relatively small and unregulated practices. We adapted the collaborative care model for the treatment of Major Depressive Disorder (MDD) to accommodate existing practice variation and tested whether this had added value over Car...
Article
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The aim of this study was to examine unique and common causes of problems in reading and arithmetic fluency. 13- to 14-year-old students were placed into one of five groups: reading disabled (RD, n = 16), arithmetic disabled (AD, n = 34), reading and arithmetic disabled (RAD, n = 17), reading, arithmetic, and listening comprehension disabled (TRIPL...
Article
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Randomised controlled trial to evaluate the effectiveness of collaborative care in a Dutch occupational healthcare setting: 126 workers on sick leave with major depressive disorder were randomised to usual care (n = 61) or collaborative care (n = 65). After 3 months, collaborative care was more effective on the primary outcome measure of treatment...
Article
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Return to work (RTW) of employees on sick leave for common mental disorders may require a multidisciplinary approach. This article aims to assess time to RTW after a psychiatric consultation providing treatment advice to the occupational physician (OP) for employees on sick leave for common mental disorders in the occupational health (OH) setting,...
Article
In the setting of multiple remission and relapse periods of a chronic disease, simple endpoint analysis does not fully capture all relevant information, and we need methods to additionally describe both the duration of remission as well as the interruptions in this desired state. Probably the two-state continuous Markov process model comprises the...
Article
Full-text available
Background: Panic disorder (PD) and generalized anxiety disorder (GAD) are two of the most disabling and costly anxiety disorders seen in primary care. However, treatment quality of these disorders in primary care generally falls beneath the standard of international guidelines. Collaborative stepped care is recommended for improving treatment of...
Article
Van Marwijk HWJ, Ader H, De Haan M, Beekman A. Disease management voor depressieve patiënten van 55+. Uitkomsten van een gerandomiseerd onderzoek. Huisarts Wet 2009;52(6):281-6. Doel Wij evalueerden de gevolgen van een interventieprogramma dat probeerde de identificatie, diagnose en behandeling van depressie te verbeteren bij patiënten van ≥ 55 ja...
Article
Background: Minor depression is common in primary care and associated with increased health care costs. Many mildly depressed patients are prescribed antidepressants, although there is insufficient information on the cost-effectiveness of antidepressants for these patients. The objective of this study was to evaluate whether usual care without anti...
Article
In this chapter we discuss two related concepts, both relevant to research methodology. The are, time and strategy. We will first consider research situations in which temporal considerations play an important part. As part of the notion of strategy, temporal ordering is essential: it can only be described indicating the chronological order of the...
Article
Full-text available
Late-life depression is associated with chronic illness, disability, and a poor prognosis. Primary care management may be in need of improvement. To compare the effects of an intervention programme that aims to improve the identification, diagnosis, and treatment of depression in patients aged > or =55 years with the effects of usual care. Cluster...
Article
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Hermens MLM, Van Hout HPJ, Terluin B, Adèr HJ, Penninx BWJH, Van Marwijk HWJ, Bosmans JE, Van Dyck R, De Haan M. Helpen antidepressiva bij depressieve klachten of lichte depressieve stoornissen? Huisarts Wet 2008;51(8):361-9. Achtergrond Depressieve klachten en lichte depressieve stoornissen komen in de huisartsenpraktijk veel voor. Er is onvoldoe...
Article
In a 3-year epidemiological survey (N=2623) prevalence of psychosis in epilepsy patients as compared with other chronic medically ill patients is assessed. To explore the role of cerebral pathology as compared to the role of chronic burden of disease in the onset of psychosis. One thousand seven hundred fifty two patients with chronic medical disor...
Article
Full-text available
Background: Minor and mild-major depression are highly prevalent in primary care. There is insufficient evidence that antidepressants are effective in the treatment of minor and mild-major depression. We compared the effectiveness of usual primary care treatment, with or without antidepressants, in minor and mild-major depression. Method: We conduc...
Article
An effective treatment already exists for many diseases. In these cases the effectiveness of a new treatment may be established by showing that the new treatment is as effective as (i.e., equivalent to) or at least as effective as (i.e., noninferior to) the old treatment. For an economic evaluation accompanying a clinical equivalence or noninferior...
Article
Full-text available
Minor and mild-major depression are highly prevalent in primary care. There is insufficient evidence for the effectiveness of antidepressants in the treatment of minor and mild-major depression. We compared the effectiveness of usual primary care treatment, with or without antidepressants, in minor and mild-major depression. A pragmatic patient-ran...
Article
Interpersonal psychotherapy (IPT) is recommended in most depression treatment guidelines, but little is known about its effectiveness in real-life practice. This study investigates whether IPT, delivered by mental health workers to elderly patients with major depressive disorder, is more effective than usual general practitioners' care (CAU). A pra...
Data
Full-text available
Responsiveness. Paper assessing the responsiveness of the 4DSQ scales, using the data of study I.
Data
Full-text available
Respondent burden. Paper assessing the time needed to fill in the 4DSQ, using the data of study J.
Data
Full-text available
Reliability, precision and smallest detectable change. Paper assessing the reliability, precision and smallest detectable change of the 4DSQ scales, using the data of studies C through J.
Article
Van der Feltz-Cornelis CM, Van Oppen P, Adèr HJ, Van Dyck R. Collaborative care voor lichamelijk onverklaarde klachten in de huisartsenpraktijk. Uitkomst en opbrengst voor de huisarts. Huisarts Wet 2006;49(7):342-7. Achtergrond Patiënten met lichamelijk onverklaarde klachten functioneren over het algemeen slecht en lijden vaak aan comorbide psychis...
Article
Full-text available
Questions addressed are: (1) Does offering prenatal screening increase anxiety? (2) Does receiving a negative screening result make women less anxious and does a positive screening result make women more anxious? (3) What are the long-term consequences on anxiety of offering screening and receiving a screening result? Women were offered prenatal sc...
Article
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Carpal tunnel syndrome (CTS) is a common disorder, often treated with surgery or wrist splinting. The objective of this economic evaluation alongside a randomized trial was to evaluate the cost-effectiveness of splinting and surgery for patients with CTS. Patients at 13 neurological outpatient clinics with clinically and electrophysiologically conf...
Article
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The Four-Dimensional Symptom Questionnaire (4DSQ) is a self-report questionnaire that has been developed in primary care to distinguish non-specific general distress from depression, anxiety and somatization. The purpose of this paper is to evaluate its criterion and construct validity. Data from 10 different primary care studies have been used. Cr...
Article
Patients with persistent medically unexplained symptoms often exhibit general dysfunction and psychiatric comorbidity and frequently resist psychiatric referral. The aim of this study was to evaluate the efficacy of a collaborative care model including training for general practitioners (GPs) and a psychiatric consultation model for patients with p...
Article
Full-text available
The Montgomery Asberg Depression Rating Scale (MADRS) is a frequently used observer-rated depression scale. In the present study, a telephonic rating was compared with a face-to-face rating in 66 primary care patients with minor or mild-major depression. The aim of the present study was to assess the validity of the administration by telephone. Add...
Article
Full-text available
BACKGROUND: The Four-Dimensional Symptom Questionnaire (4DSQ) is a self-report questionnaire that has been developed in primary care to distinguish non-specific general distress from depression, anxiety and somatization. The purpose of this paper is to evaluate its criterion and construct validity. METHODS: Data from 10 different primary care studi...
Article
Full-text available
About 25-40% of hospital patients are malnourished. With current clinical practices, only 50% of malnourished patients are identified by the medical and nursing staff. The objective of this study was to report the cost and effectiveness of early recognition and treatment of malnourished hospital patients with the use of the Short Nutritional Assess...
Article
Histopathologic studies suggest that lesion development differs between patients with multiple sclerosis (MS), but that all lesions appear similar within patients. It is unclear whether the same applies to the evolution of lesions on T1-weighted MRI. To evaluate lesion evolution on MRI, comparing variance within and between patients, as well as the...
Article
Factor analysis is widely used to evaluate whether questionnaire items can be grouped into clusters representing different dimensions of the construct under study. This review focuses on the appropriate use of factor analysis. The Medical Outcomes Study Short Form-36 (SF-36) is used as an example. Articles were systematically searched and assessed...
Article
Full-text available
This study examines secondary traumatization among 708 partners and 332 parents of Dutch peacekeepers (i.e., personnel who participated in military actions implemented by international organizations such as the United Nations). Partners or parents of peacekeepers with 4 levels of posttraumatic stress symptoms were compared on posttraumatic stress,...
Article
To examine the effect of integrated emotion-oriented care on nursing home residents with dementia and nursing assistants. A multi-site randomized clinical trial with matched groups, and measurements at baseline and after seven months. Sixteen psychogeriatric wards in fourteen nursing homes in the Netherlands. One hundred and forty-six elderly resid...
Article
The aim of this study was to assess whether a cut-off of five on the 15-item version of the Geriatric Depression Scale (GDS)that was determined beforehand yielded the best sensitivity and specificity for the diagnosis of major depression in the elderly in primary care. A sample of 330 patients was drawn from a group of elderly patients (⩽ 55 years)...
Article
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To correlate quantitative magnetic resonance (MR) imaging data (ie, relaxation times and magnetization transfer ratios [MTRs]) with histopathologic findings of demyelination and axonal disease in cervical spinal cord specimens from patients with multiple sclerosis (MS) and control subjects. Formaldehyde-fixed cervical spinal cord specimens from 11...
Article
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To describe the effect of indirect costs for patients with early rheumatoid arthritis (RA) within the COBRA trial (Combinatietherapie Bij Reumatoide Artritis) on the cost-effectiveness of both therapies. Analyses of the efficacy and direct costs of the treatments have already been reported. Patients with early RA selected for the 56-week trial were...
Article
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Bone mineral density (BMD) measurements are frequently performed repeatedly for each patient. Subsequent BMD measurements allow reproducibility to be assessed. To examine the reproducibility of BMD by dual energy x ray absorptiometry (DXA) and to investigate the practical value of different measures of reproducibility in a group of postmenopausal w...
Conference Paper
We discuss the use of diagrams in support of empirical research. In particular, we try to find out if an analysis of a diagram that represents the results from a series of qualitative studies, can be used to formulate subsequent (quantitative or qualitative) research.
Article
To determine the attitudes of potential providers (general practitioners and Community Health Service workers) towards preconceptional cystic fibrosis (CF) carrier screening and to determine which factors are associated with a positive attitude. A survey was conducted among 200 general practitioners (GPs) and 134 Community Health Service (CHS) work...
Article
Full-text available
Terluin B, Van Hout HPJ, Van Marwijk HWJ, Adèr HJ, Van der Meer K, De Haan M, Van Dyck R. Diagnose depressie niet zo betrouwbaar te stellen. Huisarts Wet 2004;47(2):66-70. Doelstelling Het diagnosticeren van een depressie is een ingewikkelde zaak. De huisarts moet negen depressieve symptomen nagaan en rekening houden met twee kernsymptomen. Bij in...
Article
The aim of this study was to assess the attitudes and intentions of individuals planning a pregnancy with regard to preconceptional cystic fibrosis (CF) carrier screening and to determine factors associated with a positive and negative/neutral intention to have the test. A survey, based on a questionnaire, was conducted among a stratified random sa...
Article
Full-text available
Lateral epicondylitis is a common complaint, with an annual incidence between 1% and 3% in the general population. The Dutch College of General Practitioners in The Netherlands has issued guidelines that recommend a wait-and-see policy. However, these guidelines are not evidence based. This paper presents the results of an economic evaluation in co...
Article
The most recent diagnostic criteria for multiple sclerosis (MS) ascertain that findings from spinal cord MRI can be used to demonstrate dissemination in space. Because little is known about the prevalence and characteristics of cord lesions early in the disease, the authors studied the prevalence of spinal cord abnormalities in patients with early-...
Article
The aim of this study is to identify a subset of women presenting with preterm labor not responding upon tocolytic therapy, eventually resulting in preterm birth. The maternal admission characteristics of 185 women with preterm labor receiving tocolysis were analysed for risk factors that could predict which women will deliver within 48 h after the...
Article
The Discomfort Scale--Dementia of Alzheimer Type (DS-DAT) measures discomfort in severely demented patients with scores on nine items with behavioral descriptors. Direct observation of behaviour is the preferred method in severely demented patients, but is not feasible for some types of research. Alternatively, a patient's score may be assessed 're...
Article
There are different kinds of randomised controlled trials: trials in which the superiority of a treatment can be demonstrated (superiority trials) and trials in which the equal efficacy of two treatments can be shown (equivalence trials). The main reason for performing an equivalence trial is that for many diseases and disorders an effective treatm...
Article
Specific T-cell subsets and their ability to produce cytokines have been involved in concepts of multiple sclerosis (MS) pathogenesis. Evidence to link cytokine producing T-cell subsets to magnetic resonance imaging (MRI) features of tissue destruction, however, is limited. Cytokine flow cytometry was performed in 124 patients with different subtyp...
Article
The purpose of this study is to compare the hemodynamic and metabolic changes after ritodrine and nifedipine tocolysis. For an open randomized study, patients with preterm labor (N=185) were allocated to groups to receive ritodrine intravenously (N=90) or nifedipine orally (N=95). The mean diastolic blood pressure was significantly lower in the rit...
Article
The aim of this study was to investigate whether the activities and attitudes of general practitioners (GPs) concerning genetic counseling have changed between 1989 and 1999. In 1989 a random sample of 124 GPs in The Netherlands was selected. Of these GPs, 98 were contacted again in 1999 and 71 completed the questionnaire. The study showed an incre...