Mark de Rooij

Comorbidity of PTSD in anxiety and depressive disorders: prevalence and shared risk factors

The present study aims to assess comorbidity of posttraumatic stress disorder (PTSD) in anxiety and depressive disorders and to determine whether childhood trauma types and other putative independent risk factors for comorbid PTSD are unique to PTSD or shared with anxiety and depressive disorders. The sample of 2402 adults aged 18-65 included healthy controls, persons with a prior history of affective disorders, and persons with a current affective disorder. These individuals were assessed at baseline (T0) and 2 (T2) and 4 years (T4) later. At each wave, DSM-IV-TR based anxiety and depressive disorder, neuroticism, extraversion, and symptom severity were assessed. Childhood trauma was measured at T0 with an interview and at T4 with a questionnaire, and PTSD was measured with a standardized interview at T4. Prevalence of 5-year recency PTSD among anxiety and depressive disorders was 9.2%, and comorbidity, in particular with major depression, was high (84.4%). Comorbidity was associated with female gender, all types of childhood trauma, neuroticism, (low) extraversion, and symptom severity. Multivariable significant risk factors (i.e., female gender and child sexual and physical abuse) were shared among anxiety and depressive disorders. Our results support a shared vulnerability model for comorbidity of anxiety and depressive disorders with PTSD. Routine assessment of PTSD in patients with anxiety and depressive disorders seems warranted.

A longitudinal study of experiential avoidance in emotional disorders

The aim of this study was to examine the degree in which measurements of trait experiential avoidance (EA) are affected by current emotional disorder and whether EA is a causal factor in the course of emotional disorders (anxiety and depressive disorders) and the development of comorbidity among emotional disorders. In a sample of 2,316 adults aged 18 to 65, consisting of healthy controls, persons with a prior history of emotional disorders, and persons with a current emotional disorder, DSM-IV-based emotional disorders (CIDI: Composite Interview Diagnostic Instrument) were assessed at T2 and 2 (T4) and 4years later (T6) and experiential avoidance (AAQ: Acceptance and Action Questionnaire) at T2 and T4. Results showed that EA scores were stable over a 2-year period notwithstanding state fluctuations because of current emotional disorder. Moreover, EA scores at T2 predicted changes in distress (major depressive disorder, dysthymia, generalized anxiety disorder) and in fear disorders (social anxiety disorder, panic disorder with or without agoraphobia, agoraphobia without panic) at T4. Finally, EA at T4 mediated the longitudinal association of fear disorders at T2 with distress disorders at T6 as well as of distress disorders at T2 with fear disorders at T6. These findings suggest that EA scores are more than epiphenomena of emotional disorders and that EA may be conceptualized as a relevant transdiagnostic factor affecting the course and development of comorbidity of emotional disorders.

The role of personality in comorbidity among anxiety and depressive disorders in primary care and specialty care: a cross-sectional analysis.

OBJECTIVE Almost no cross-sectional studies directly compared the rate and pattern of comorbidity of affective disorders in relation to personality traits of patients seen in primary care versus specialty mental health care. METHOD Using data from the Netherlands Study of Depression and Anxiety, we compared 1086 primary care patients with 790 consecutive specialized mental health care patients. All participants had at least one lifetime Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition-based diagnosis of depression or anxiety. Personality was assessed with the NEO Five-Factor Inventory. RESULTS In both settings it was common to have at least one lifetime comorbid affective disorder. Compared to primary care patients, specialty care patients showed elevated scores for Neuroticism and lower scores for Extraversion and Conscientiousness. The odds of having another disorder given any one disorder was no longer significant after accounting for personality dimensions. Only Neuroticism proved to be positively associated with comorbidity per se. CONCLUSIONS Prevalence of and comorbidity among anxiety and depressive disorders in primary care were very similar to those in specialty care. Neuroticism - but no other personality traits - may help to understand the comorbidity among anxiety and depressive disorders irrespective of recruitment setting.

Combining anatomical, diffusion, and resting state functional magnetic resonance imaging for individual classification of mild and moderate Alzheimer's disease

Magnetic resonance imaging (MRI) is sensitive to structural and functional changes in the brain caused by Alzheimers disease (AD), and can therefore be used to help in diagnosing the disease. Improving classification of AD patients based on MRI scans might help to identify AD earlier in the diseases progress, which may be key in developing treatments for AD. In this study we used an elastic net classifier based on several measures derived from the MRI scans of mild to moderate AD patients (N = 77) from the prospective registry on dementia study and controls (N = 173) from the Austrian Stroke Prevention Family Study. We based our classification on measures from anatomical MRI, diffusion weighted MRI and resting state functional MRI. Our unimodal classification performance ranged from an area under the curve (AUC) of 0.760 (full correlations between functional networks) to 0.909 (grey matter density). When combining measures from multiple modalities in a stepwise manner, the classification performance improved to an AUC of 0.952. This optimal combination consisted of grey matter density, white matter density, fractional anisotropy, mean diffusivity, and sparse partial correlations between functional networks. Classification performance for mild AD as well as moderate AD also improved when using this multimodal combination. We conclude that different MRI modalities provide complementary information for classifying AD. Moreover, combining multiple modalities can substantially improve classification performance over unimodal classification.

Combining multiple anatomical MRI measures improves Alzheimer's disease classification

Several anatomical MRI markers for Alzheimers disease (AD) have been identified. Hippocampal volume, cortical thickness, and grey matter density have been used successfully to discriminate AD patients from controls. These anatomical MRI measures have so far mainly been used separately. The full potential of anatomical MRI scans for AD diagnosis might thus not yet have been used optimally. In this study, we therefore combined multiple anatomical MRI measures to improve diagnostic classification of AD. For 21 clinically diagnosed AD patients and 21 cognitively normal controls, we calculated (i) cortical thickness, (ii) cortical area, (iii) cortical curvature, (iv) grey matter density, (v) subcortical volumes, and (vi) hippocampal shape. These six measures were used separately and combined as predictors in an elastic net logistic regression. We made receiver operating curve plots and calculated the area under the curve (AUC) to determine classification performance. AUC values for the single measures ranged from 0.67 (cortical thickness) to 0.94 (grey matter density). The combination of all six measures resulted in an AUC of 0.98. Our results demonstrate that the different anatomical MRI measures contain complementary information. A combination of these measures may therefore improve accuracy of AD diagnosis in clinical practice. Hum Brain Mapp 37:1920–1929, 2016.

Peer Victimization Experienced by Children and Adolescents Who Are Deaf or Hard of Hearing

Victimization is a relatively common, yet serious problem, with potentially severe consequences for childrens psychosocial and academic functioning. Children who are Deaf or Hard of Hearing (DHH) may be at a higher risk for victimization than hearing children. The aims of the present study were to compare DHH and hearing children on i) self-reported experiences of victimization and ii) associations between victimization, parental- and child variables. In total 188 children (mean age 11;11 years) from the Netherlands and Dutch-speaking part of Belgium participated in the study. No difference between DHH and hearing children were found on general experiences of victimization. However, differences between the groups were found on specific forms of experienced victimization and on the associations between victimization and parental variables. For DHH children, parental sensitivity and parents who challenge their DHH children to become competent in the practical, emotional, cognitive and social domain is associated with them being less victimized. For hearing children at this age these relations were reversed, absent or more complex. Finally, DHH children in special schools were more victimized than DHH children in regular schools. It can be concluded that parents can play an important role in reducing social problems experienced by DHH children and young adolescents.

Ketamine interactions with biomarkers of stress: a randomized placebo-controlled repeated measures resting-state fMRI and PCASL pilot study in healthy men.

Ketamine, an NMDA receptor antagonist, is increasingly used to study the link between glutamatergic signaling dysregulation and mood and chronic pain disorders. Glutamatergic neurotransmission and stress corticosteroids (cortisol in human) are critical for Ca(2+) mediated neuroplasticity and behavioral adaptation. The mechanisms of action of glutamatergic neurotransmission and stress corticosteroids on the NMDA-receptors of the hippocampus have been long investigated in animals, but given little attention in human studies. In this randomized single-blinded placebo-controlled crossover study (12 healthy young men), five sets of resting-state fMRI (RSFMRI), pseudocontinuous arterial spin labeling (PCASL), and corresponding salivary cortisol samples were acquired over 4h, at given intervals under pharmacokinetically-controlled infusion of subanesthetic ketamine (20 & 40mg/70kg/h). An identical procedure was repeated under a sham placebo condition. Differences in the profile of ketamine versus placebo effect over time were examined. Compared to placebo, ketamine mimicked a stress-like response (increased cortisol, reduced calmness and alertness, and impaired working memory). Ketamine effects on the brain included a transient prefrontal hyperperfusion and a dose-related reduction of relative hippocampal perfusion, plus emerging hyperconnectivity between the hippocampus and the occipital, cingulate, precuneal, cerebellar and basal ganglia regions. The spatiotemporal profiles of ketamine effects on different hippocampal subnetworks suggest a topographically dissociable change in corticohippocampal functional connectivity. We discuss our findings in the context of the negative feedback inhibition theory of the hippocampal stress-control. This pilot study provides a methodological framework for multimodal functional neuroimaging under resting-state conditions, which may be generalized for translational studies of glutamatergic- or stress-related etiology of neuropsychiatric disorders.

Development of Equity Preferences in Boys and Girls Across Adolescence

The aim of the current study was to examine the development of equity preferences across adolescence, for boys and girls separately. Participants from 8 to 18 years old (M = 14.09 years; N = 1,216) played four economic allocation games. Analyses revealed a decrease in equity preferences with age and this decrease was stronger for boys than for girls. There was also an age-related increase in the preference for efficient outcomes (i.e., maximization of total available resources), which was again stronger for boys than for girls. Overall, although equity remains as a strong social norm, adolescents are decreasingly strict in adhering to the equity norm and show increasing flexibility in equity preferences.

A Comparison of the Multidimensional Scaling of Triadic and Dyadic Distances

We examine the use of triadic distances as a basis for multidimensional scaling (MDS). The MDS of triadic distances (MDS3) and a conventional MDS of dyadic distances (MDS2) both give Euclidean representations. Our analysis suggests that MDS2 and MDS3 can be expected to give very similar results, and this is strongly supported by numerical examples. We have concentrated on the perimeter and generalized Euclidean models of triadic distances, both of which are linear transformations of dyadic distances and so might be suspected of explaining our findings; however an MDS3 of the nonlinear variance definition of triadic distance also closely approximated the MDS2 representation. An appendix gives some matrix results that we have found useful and also gives matrix respresentations and alternative derivations of some known properties of triadic distances.

Triadic distance models for the analysis of asymmetric three-way proximity data

Triadic distance models can be used to analyse proximity data defined on triples of objects. Three-way symmetry is a common assumption for triadic distance models. In the present study three-way symmetry is not assumed. Triadic distance models are presented for the analysis of asymmetric three-way proximity data that result in a simultaneous representation of symmetry and asymmetry in a low-dimensional configuration. An iterative majorization algorithm is developed for obtaining the coordinates and the representation of the asymmetry. The models are illustrated by an example using longitudinal categorical data.