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Dive into the research topics where Anita C. Volkers is active.

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Featured researches published by Anita C. Volkers.


Psychological Medicine | 2005

Accuracy of diagnosing depression in primary care: the impact of chronic somatic and psychiatric co-morbidity.

Jasper Nuyen; Anita C. Volkers; Peter F. M. Verhaak; F.G. Schellevis; Peter P. Groenewegen; Geertrudis A.M. van den Bos

BACKGROUNDnDepression is highly co-morbid with both psychiatric and chronic somatic disease. These types of co-morbidity have been shown to exert opposite effects on underdiagnosis of depression by general practitioners (GPs). However, past research has not addressed their combined effect on underdiagnosis of depression.nnnMETHODnCo-morbidity data on 191 depressed primary-care patients selected by a two-stage sampling procedure were analysed. Diagnoses of major depression and/or dysthymia in the last 12 months were assessed using a standardized psychiatric interview (CIDI) and compared with depression diagnoses registered by GPs in patient contacts during the same period. Presence of psychiatric and chronic somatic co-morbidity was determined using the CIDI and contact registration, respectively.nnnRESULTSnRegression analysis showed a significant interaction effect between psychiatric and chronic somatic co-morbidity on GPs diagnosis of depression, while taking into account the effects of sociodemographic variables, depression severity and number of GP contacts. Subsequent stratified analysis revealed that in patients without chronic somatic co-morbidity, a lower educational level, a less severe depression, and fewer GP contacts all significantly increased the likelihood of not being diagnosed as depressed. In contrast, in patients with chronic somatic co-morbidity, only having no psychiatric co-morbidity significantly decreased the likelihood of receiving a depression diagnosis.nnnCONCLUSIONSnOur results indicate that the effects of psychiatric co-morbidity and other factors on underdiagnosis of depression by GPs differ between depressed patients with and without chronic somatic co-morbidity. Efforts to improve depression diagnosis by GPs seem to require different strategies for depressed patients with and without chronic somatic co-morbidity.


Journal of Affective Disorders | 2003

Motor activity and autonomic cardiac functioning in major depressive disorder

Anita C. Volkers; J.H.M. Tulen; Walter W. van den Broek; Jan A. Bruijn; Jan Passchier; Lolke Pepplinkhuizen

BACKGROUNDnThe daily pattern of motor activity and the autonomic cardiovascular regulation were studied in major depression to quantify changes in psychomotor function and autonomic cardiac functioning. Additionally, relationships between motor activity parameters, cardiovascular measures and specific clinical features were examined.nnnMETHODSnWrist-actigraphy was used to monitor 24-h motor activity for 67 unmedicated (unipolar) depressed inpatients and 64 control subjects. During supine rest, spectral analysis was applied to assess HR and SBP variability, a baroreflex sensitivity (BRS) index and the respiratory frequency, in addition to mean heart rate (HR) and blood pressure (BP) levels for the patient group and a second control group (N=51).nnnRESULTSnThe patients showed a lower motor activity level and a reduced fragmentation of motor activity during wake, and a higher motor activity level and a decreased immobility during sleep. The mean HR and DBP level and the respiratory frequency were higher in the patient group than in the control group, but no differences in HR and SBP variability or BRS were found. Furthermore, motor activity parameters and cardiovascular measures of the patients were related to agitation and retardation and overall, patients with lower motor activity levels demonstrated lower SBP levels.nnnCONCLUSIONSnThis study confirms that the 24-h pattern of motor activity is altered in unmedicated depressed inpatients, but limited evidence was found for an autonomic cardiac dysfunction. Within the patient group there were relationships between motor activity parameters, cardiovascular measures, and clinical features, but the underlying neurobiological pathways need to be further explored.


Journal of Psychiatric Research | 2002

CPT performance in major depressive disorder before and after treatment with imipramine or fluvoxamine

Gerard C Koetsier; Anita C. Volkers; J.H.M. Tulen; Jan Passchier; Walter W. van den Broek; Jan A. Bruijn

Numerous neuropsychological studies have reported deficits in cognitive and attentional functioning in depressed patients. However, there are limited data available about unmedicated depressed patients and the effects of antidepressant treatment on attentional performance. In this study, a Continuous Performance Test (CPT) was employed to evaluate the attentional performance of depressed inpatients during a drugfree period (n = 52) in comparison to healthy control subjects (n = 73). After 4 weeks of double-blind treatment with imipramine (TCA) or fluvoxamine (SSRI) at adequate plasma levels the CPT performance was studied again. We found that the unmedicated patients had a significantly impaired performance on all CPT parameters (reaction time, omission errors and commission errors) in comparison to the controls. None of the CPT parameters correlated with the severity of the depression or the level of psychomotor retardation. However, the CPT performance in the patient group was significantly related to subjective mood state (depression, tension). Double-blind treatment with imipramine or fluvoxamine resulted in an improvement of the CPT performance. In the imipramine treatment group the mean reaction time decreased significantly, and after treatment with fluvoxamine a significant decrease of the mean reaction time and the number of omission errors was detected. Both antidepressants induced a significant improvement of clinical state, but we did not find a relationship between the altered CPT performance and the changes on the clinical scales. Future studies should investigate other mechanisms underlying the improved attentional performance after treatment.


European Neuropsychopharmacology | 2002

24-Hour motor activity after treatment with imipramine or fluvoxamine in major depressive disorder

Anita C. Volkers; J.H.M. Tulen; Walter W. van den Broek; Jan A. Bruijn; Jan Passchier; Lolke Pepplinkhuizen

Psychomotor dysfunction in depression is related to alterations in the 24-h pattern of motor activity. After antidepressant treatment the diurnal pattern may be changed due to improvement of clinical state or pharmacological actions. The purpose of this study was to evaluate in 52 depressed in-patients the effects of imipramine (tricyclic antidepressant) and fluvoxamine (SSRI) on the 24-h motor activity. Motor activity was monitored by wrist-actigraphy during a medication-free period and after 4 weeks of treatment. Clinical improvement was not different after imipramine or fluvoxamine treatment. The Hamilton depression score decreased in patients treated with imipramine, as well as in patients treated with fluvoxamine. The clinical retardation score was also reduced in both treatment groups. However, patients treated with imipramine showed higher motor activity levels during the wake period in comparison to the medication-free period, and more fragmentation of motor activity during sleep. Treatment with fluvoxamine did not result in alterations in the 24-h pattern of motor activity. The improvement of depressive mood and retardation seems to play a minor role in the change of the pattern of motor activity after imipramine.


BMC Public Health | 2007

Health disparities by occupation, modified by education: a cross-sectional population study.

Anita C. Volkers; G.P. Westert; F.G. Schellevis

BackgroundSocio-economic disparities in health status are frequently reported in research. By comparison with education and income, occupational status has been less extensively studied in relation to health status or the occurrence of specific chronic diseases. The aim of this study was to investigate health disparities in the working population based on occupational position and how they were modified by education.MethodsOur data were derived from the National Survey of General Practice that comprised 104 practices in the Netherlands. 136,189 working people aged 25–64 participated in the study. Occupational position was assessed by the International Socio-Economic Index of occupational position (ISEI). Health outcomes were self-perceived health status and physician-diagnosed diseases. Odds ratios were estimated using multivariate logistic regression analysis.ResultsThe lowest occupational position was observed to be associated with poor health in men (OR = 1.6, 95% CI 1,5 to 1.7) and women (OR = 1.3, 95% CI 1.2 to 1.4). The risk of poor health gradually decreased in relation to higher occupational positions. People with the lowest occupational positions were more likely to suffer from depression, diabetes, ischaemic heart disease, arthritis, muscle pain, neck and back pain and tension headache, in comparison to people with the highest occupational position (OR 1.2 to 1.6). A lower educational level induced an additional risk of poor health and disease. We found that gender modified the effects on poor health when both occupational position and education were combined in the analysis.ConclusionA low occupational position was consistently associated working people with poor health and physician-diagnosed morbidity. However a low educational level was not. Occupational position and education had a combined effect on self-perceived health, which supports the recent call to improve the conceptual framework of health disparities.


Journal of Personality | 2002

Effect of personality dimensions on the diurnal pattern of motor activity.

Anita C. Volkers; J.H.M. Tulen; Hugo J. Duivenvoorden; Marieke J. Gieteling; Marlies Wegewijs‐De Jong; Walter W. van den Broek; Jan Passchier; Lolke Pepplinkhuizen

The effects of personality dimensions, age, and gender on 24-hour motor activity patterns were studied in 101 healthy subjects between 20-70 years. We measured motor activity by wrist-actigraphy and personality dimensions by the Tridimensional Personality Questionnaire (TPQ) of Cloninger. Random Regression Models were used to estimate the effects of personality dimensions, age, and gender on the diurnal pattern of motor activity. Harm Avoidance as well as Reward Dependence influenced the overall level of motor activity, independent of age and gender. Subjects high on Harm Avoidance showed lower activity levels than subjects low on Harm Avoidance, whereas subjects high on Reward Dependence had higher overall levels of motor activity than subjects low on Reward Dependence. Older subjects were found to be less active than younger subjects, but the activity level did not differ between males and females.


Journal of Affective Disorders | 2004

The problem of diagnosing major depression in elderly primary care patients

Anita C. Volkers; Jasper Nuyen; Peter F. M. Verhaak; F.G. Schellevis


General Hospital Psychiatry | 2006

Patients with a psychiatric disorder in general practice: determinants of general practitioners' psychological diagnosis

Peter F. M. Verhaak; F.G. Schellevis; Jasper Nuijen; Anita C. Volkers


Pharmacopsychiatry | 2004

Effects of imipramine, fluvoxamine and depressive mood on autonomic cardiac functioning in major depressive disorder.

Anita C. Volkers; J.H.M. Tulen; Walter W. van den Broek; Jacqueline De Bruyn; Jan Passchier; Lolke Pepplinkhuizen


Journal of Clinical Psychopharmacology | 2006

Sustained effects of phenelzine and tranylcypromine on orthostatic challenge in antidepressant-refractory depression.

J.H.M. Tulen; Anita C. Volkers; Walter W. van den Broek; Jan A. Bruijn

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F.G. Schellevis

VU University Medical Center

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J.H.M. Tulen

Erasmus University Rotterdam

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Jan A. Bruijn

Erasmus University Rotterdam

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Lolke Pepplinkhuizen

Erasmus University Rotterdam

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Peter F. M. Verhaak

University Medical Center Groningen

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