39 research outputs found

    Transcranial Magnetic theta-burst stimulation of the human cerebellum distinguishes absolute, duration-based from relative, beat-based perception of subsecond time intervals

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    Cerebellar functions in two types of perceptual timing were assessed: the absolute (duration-based) timing of single intervals and the relative (beat-based) timing of rhythmic sequences. Continuous transcranial magnetic theta-burst stimulation (cTBS) was applied over the medial cerebellum and performance was measured adaptively before and after stimulation. A large and significant effect was found in the TBS (n = 12) compared to the SHAM (n = 12) group for single-interval timing but not for the detection of a regular beat or a deviation from it. The data support the existence of distinct perceptual timing mechanisms and an obligatory role of the cerebellum in absolute interval timing with a functional dissociation from relative timing of interval within rhythmic sequences based on a regular beat

    Qatar's national mental health study—the world mental health Qatar

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    Background We provide an overview of Qatar's first epidemiological study on prevalence, predictors, and treatment contact for mood and anxiety disorders. Aims We highlight the importance of the three-pronged study, its aims, and its key components. Materials & Methods The first component comprised a probability-based representative survey of Qatari and non-Qatari (Arab) adult males and females recruited from the general population and interviewed using the International Diagnostic Interview (CIDI version 3.3). The second component, a clinical reappraisal study, assessed concordance between diagnoses based on the CIDI and independent clinical assessments conducted by trained clinical interviewers. The third component comprised a resting-state functional magnetic resonance imaging study of healthy survey respondents who were matched to patients with psychosis. Results 5000 survey interviews provided data on prevalence and treatment of common mental disorders. Clinical re-interviews (N = 485) provided important diagnostic validity data. Finally, state-of-the art structural and functional brain markers for psychosis were also collected (N = 100). Discussion Descriptive epidemiological data were collected to inform future mental health priorities in Qatar and situates these within a global context. Conclusion The study fills important gaps in regional and global estimates and establish necessary baseline to develop comprehensive risk estimates for mental health in Qatar’s young population

    Cross-cultural differences in hallucinations: A comparison between Middle Eastern and European community-based samples

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    Background and Hypothesis While literature indicates that culture modulates phenomenological characteristics of hallucinations in schizophrenia-spectrum disorders, little is known about the extent culture modulates these characteristics in nonclinical samples. Study Design We compared lifetime prevalence, age of onset, and phenomenology of hallucinations as assessed with the Questionnaire for Psychotic Experiences between samples of nonclinical participants used from the Netherlands (N = 2999) and Qatar (N = 2999). While participant recruitment differed between the 2 countries, the samples were relatively equal in terms of demographic factors. Study Results Our findings indicate that the lifetime prevalence of tactile and olfactory hallucinations are the same across countries. However, the prevalence of auditory hallucinations (AH) and visual hallucinations (VH) were twice as high in the Dutch sample. The reported age of onset for auditory and tactile hallucinations was younger for the Dutch sample. Findings from the measurement invariance supported cross-cultural comparisons with exception for duration, distress, and insight. Qatar’s and Dutch participants reported similar valence and extent of interaction with AH and VH. However, compared to those in the Netherlands, participants from Qatar reported significantly more impact on daily functioning and a higher prevalence of receiving commands from hallucinations in the past week. Conclusions While AH and VH were more often reported in the Dutch sample, participants in Qatar generally had higher mean factor scores for past week AH and VH than in the Netherlands. The phenomenology of hallucinations in the Qatar sample was of greater clinical relevance, with potentially important implications for early screening and prevention

    Twelve‐month prevalence, persistence, severity, and treatment of mood and anxiety disorders in Qatar's national mental health study

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    Objectives To estimate 12-month prevalence, persistence, severity, and treatment of mental disorders and socio-demographic correlates in Qatar. Methods We conducted the first national population-based telephone survey of Arab adults between 2019 and 2022 using the Composite International Diagnostic Interview and estimated 12-month DSM-5 mood and anxiety disorders and their persistence (the proportion of lifetime cases who continue to meet 12-month criteria). Results The 12-month prevalence of any disorder was 21.1% (10.4% mild, 38.7% moderate, and 50.9% severe) and was associated with: younger age, female, previously married, and with persistence of any disorder. Persistence was 74.7% (64.0% mood and 75.6% anxiety) and was significantly associated with secondary education or lower. Minimally adequate treatment received among those with any 12-month mental disorder was 10.6% (74.6% in healthcare and 64.6% non-healthcare sectors). Severity and the number of disorders significantly associated with each other and with treatment received (χ2 = 7.24, p = 0.027) including adequate treatment within the mental health specialty sector (χ2 = 21.42, p < 0.001). Conclusions Multimorbidity and sociodemographics were associated with 12-month mental disorder. Treatment adequacy in Qatar are comparable to high-income countries. Low treatment contact indicate need for population-wide mental health literacy programes in addition to more accessible and effective mental health services

    Lifetime prevalence, risk, and treatment of mood and anxiety disorders in Qatar's national mental health study

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    Objectives To estimate lifetime prevalence, risk, and treatment for mental disorders and their correlates in Qatar's general population for the first time. Methods We conducted a national phone survey of 5,195 Qatari and Arab residents in Qatar (2019–2022) using the Composite International Diagnostic Interview Version 3.3 and estimated lifetime mood and anxiety defined diagnoses. Survival-based discrete time models, lifetime morbid risk, and treatment projections were estimated. Results Lifetime prevalence of any disorder was 28.0% and was associated with younger cohorts, females, and migrants, but lower formal education. Treatment contact in the year of disorder onset were 13.5%. The median delay in receiving treatment was 5 years (IQR = 2–13). Lifetime treatment among those with a lifetime disorder were 59.9% for non-healthcare and 63.5% for healthcare; it was 68.1% for any anxiety and 80.1% for any mood disorder after 50 years of onset. Younger cohorts and later age of onset were significantly predictors of treatment. Conclusions Lifetime prevalence of mental disorders in Qatar is comparable to other countries. Treatment is significantly delayed and delivered largely in non-healthcare sectors thus the need for increased literacy of mental illness to reduce stigma and improve earlier help-seeking in healthcare settings

    Abnormal corneal nerve morphology and brain volume in patients with schizophrenia

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    Neurodevelopmental and neurodegenerative pathology occur in Schizophrenia. This study compared the utility of corneal confocal microscopy (CCM), an ophthalmic imaging technique with MRI brain volumetry in quantifying neuronal pathology and its relationship to cognitive dysfunction and symptom severity in schizophrenia. Thirty-six subjects with schizophrenia and 26 controls underwent assessment of cognitive function, symptom severity, CCM and MRI brain volumetry. Subjects with schizophrenia had lower cognitive function (P ≤ 0.01), corneal nerve fiber density (CNFD), length (CNFL), branch density (CNBD), CNBD:CNFD ratio (P < 0.0001) and cingulate gyrus volume (P < 0.05) but comparable volume of whole brain (P = 0.61), cortical gray matter (P = 0.99), ventricle (P = 0.47), hippocampus (P = 0.10) and amygdala (P = 0.68). Corneal nerve measures and cingulate gyrus volume showed no association with symptom severity (P = 0.35–0.86 and P = 0.50) or cognitive function (P = 0.35–0.86 and P = 0.49). Corneal nerve measures were not associated with metabolic syndrome (P = 0.61–0.64) or diabetes (P = 0.057–0.54). The area under the ROC curve distinguishing subjects with schizophrenia from controls was 88% for CNFL, 84% for CNBD and CNBD:CNFD ratio, 79% for CNFD and 73% for the cingulate gyrus volume. This study has identified a reduction in corneal nerve fibers and cingulate gyrus volume in schizophrenia, but no association with symptom severity or cognitive dysfunction. Corneal nerve loss identified using CCM may act as a rapid non-invasive surrogate marker of neurodegeneration in patients with schizophrenia

    Design and field procedures for the clinical reappraisal of the Composite International Diagnostic Interview version 3.3 in Qatar's national mental health study

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    Background The Composite International Diagnostic Interview (CIDI) has been clinically reappraised in several studies conducted mainly in the US and Europe. This report describes the methodology used to conduct one of the Middle East's largest clinical reappraisal studies. The study was carried out in conjunction with the World Mental Health Qatar—the first national psychiatric epidemiological study of common mental disorders in the country. This study aimed to evaluate the diagnostic consistency of core modules of the newly translated and adapted Arabic version of the CIDI 5.0 against the independent clinical diagnoses based on the Structured Clinical Interview for DSM-5 (SCID-5). Methods Telephone follow-up interviews were administered by trained clinicians using the latest research edition of the SCID for DSM-5. Telephone administered interviews were key in the data collection, as the study took place during the COVID-19 pandemic. Results Overall, within 12 months, 485 interviews were completed. The response rate was 52%. Quality control monitoring documented excellent adherence of clinical interviews to the rating protocol. Conclusions The overall methods used in this study proved to be efficient and effective. For future research, instrument cultural adaptation within the cultural context is highly recommended

    Towards an integrated set of surface meteorological observations for climate science and applications

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    Observations are the foundation for understanding the climate system. Yet, currently available land meteorological data are highly fractured into various global, regional and national holdings for different variables and timescales, from a variety of sources, and in a mixture of formats. Added to this, many data are still inaccessible for analysis and usage. To meet modern scientific and societal demands as well as emerging needs such as the provision of climate services, it is essential that we improve the management and curation of available land-based meteorological holdings. We need a comprehensive global set of data holdings, of known provenance, that is truly integrated both across Essential Climate Variables (ECVs) and across timescales to meet the broad range of stakeholder needs. These holdings must be easily discoverable, made available in accessible formats, and backed up by multi-tiered user support. The present paper provides a high level overview, based upon broad community input, of the steps that are required to bring about this integration. The significant challenge is to find a sustained means to realize this vision. This requires a long-term international program. The database that results will transform our collective ability to provide societally relevant research, analysis and predictions in many weather and climate related application areas across much of the globe

    A direct demonstration of functional specialization within motion-related visual and auditory cortex of the human brain

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    AbstractBackground Physiological studies of the macaque brain have shown that there is a large expanse of visual cortex, the V5 complex, which is specialized for visual motion, and that several areas within V5 are specialized for different kinds of visual motion. In continuing work on motion-related visual cortex, we wished to chart the specialized visual motion areas in the human brain and to determine their anatomical relationship. Human subjects viewed different motion displays, and the cortical location of the increased activity produced by each stimulus was recorded. The technique of functional magnetic resonance imaging (fMRI) was used, in order to image the same subjects repeatedly.Results We found that each of the three motion stimuli activated specific parts of the V5 complex. These sites of activation overlap with V5 and, to a smaller extent, with each other. Unexpectedly, the three motion stimuli also activated neighbouring, but nonoverlapping, regions of auditory cortex that are normally activated by the perception of speech.Conclusions The three sites of activation produced by the visual motion stimuli occupy adjacent territories within the V5 complex. Components of the V5 complex are specifically connected to regions within auditory cortex
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