Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 11 de 11
Filter
Add more filters










Publication year range
1.
Psychiatry Res Neuroimaging ; 320: 111428, 2022 03.
Article in English | MEDLINE | ID: mdl-34954446

ABSTRACT

Diminished prefrontal function, dopaminergic abnormalities in the striatum and thalamus, reductions in white matter integrity and frontotemporal gray matter deficits are the most replicated findings in schizophrenia. We used four imaging modalities (18F-fluorodeoxyglucose and 18F-fallypride PET, diffusion tensor imaging, structural MRI) in 19 healthy and 25 schizophrenia subjects to assess the relationship between functional (dopamine D2/D3 receptor binding potential, glucose metabolic rate) and structural (fractional anisotropy, MRI) correlates of schizophrenia and their additive diagnostic prediction potential. Multivariate ANOVA was used to compare structural and functional image sets for identification of schizophrenia. Integration of data from all four modalities yielded better predictive power than less inclusive combinations, specifically in the thalamus, left dorsolateral prefrontal and temporal regions. Among the modalities, fractional anisotropy showed highest discrimination in white matter whereas 18F-fallypride binding showed highest discrimination in gray matter. Structural and functional modalities displayed comparable discriminative power but different topography, with higher sensitivity of structural modalities in the left prefrontal region. Combination of functional and structural imaging modalities with inclusion of both gray and white matter appears most effective in diagnostic discrimination. The highest sensitivity of 18F-fallypride PET to gray matter changes in schizophrenia supports the primacy of dopaminergic abnormalities in its pathophysiology.


Subject(s)
Fluorodeoxyglucose F18 , Schizophrenia , Benzamides , Diffusion Tensor Imaging , Humans , Magnetic Resonance Imaging , Positron-Emission Tomography , Schizophrenia/diagnosis
2.
Brain Lang ; 223: 105046, 2021 12.
Article in English | MEDLINE | ID: mdl-34763166

ABSTRACT

Reading impairments are prominent trait-like features of cognitive deficits in schizophrenia, predictive of overall cognitive functioning and presumably linked to dopaminergic abnormalities. To evaluate this, we used 18F-fallypride PET in 19 healthy and 21 antipsychotic-naïve schizophrenia subjects and correlated dopamine receptor binding potentials in relevant AFNI-derived regions and voxelwise with group performance on WRAT4 single-word reading subtest. Healthy subjects' scores were positively and linearly associated with D2/D3 receptor availability in the rectus, orbital and superior frontal gyri, fusiform and middle temporal gyri, as well as middle occipital gyrus and precuneus, all predominantly in the left hemisphere and previously implicated in reading, hence suggesting that higher dopamine receptor density is cognitively advantageous. This relationship was weakened in schizophrenia subjects and in contrast to healthy participants followed an inverted U-shaped curve both in the cortex and dorsal striatum, indicating restricted optimal range of dopamine D2/D3 receptor availability for cognitive performance in schizophrenia.


Subject(s)
Schizophrenia , Cognition , Dopamine , Humans , Positron-Emission Tomography , Reading , Receptors, Dopamine D2/metabolism , Receptors, Dopamine D3/metabolism , Schizophrenia/diagnostic imaging , Schizophrenia/metabolism
3.
Psychiatry Res Neuroimaging ; 299: 111060, 2020 05 30.
Article in English | MEDLINE | ID: mdl-32135405

ABSTRACT

Decreased fractional anisotropy and increased glucose utilization in the white matter have been reported in schizophrenia. These findings may be indicative of an inverse relationship between these measures of white matter integrity and metabolism. We used 18F-fluorodeoxyglucose positron emission tomography and diffusion-tensor imaging in 19 healthy and 25 schizophrenia subjects to assess and compare coterritorial correlation patterns between glucose utilization and fractional anisotropy on a voxel-by-voxel basis and across a range of automatically placed representative white matter regions of interest. We found a pattern of predominantly negative correlations between white matter metabolism and fractional anisotropy in both healthy and schizophrenia subjects. The overall strength of the relationship was attenuated in subjects with schizophrenia, who displayed significantly fewer and weaker correlations in all regions assessed with the exception of the corpus callosum. This attenuation was most prominent in the left prefrontal white matter and this region also best predicted the diagnosis of schizophrenia. There exists an inverse relationship between the measures of white matter integrity and metabolism, which may therefore be physiologically linked. In subjects with schizophrenia, hypermetabolism in the white matter may be a function of lower white matter integrity, with lower efficiency and increased energetic cost of task-related computations.


Subject(s)
Diffusion Tensor Imaging , Glucose/metabolism , Schizophrenia/physiopathology , White Matter/physiopathology , Anisotropy , Corpus Callosum/physiopathology , Female , Humans , Male , Positron-Emission Tomography , Young Adult
4.
World J Biol Psychiatry ; 21(5): 368-382, 2020 06.
Article in English | MEDLINE | ID: mdl-31552783

ABSTRACT

Objectives: Overlapping decreases in extrastriatal dopamine D2/D3-receptor availability and glucose metabolism have been reported in subjects with schizophrenia. It remains unknown whether these findings are physiologically related or coincidental.Methods: To ascertain this, we used two consecutive 18F-fluorodeoxyglucose and 18F-fallypride positron emission tomography scans in 19 healthy and 25 unmedicated schizophrenia subjects. Matrices of correlations between 18F-fluorodeoxyglucose uptake and 18F-fallypride binding in voxels at the same xyz location and AFNI-generated regions of interest were evaluated in both diagnostic groups.Results:18F-fluorodeoxyglucose uptake and 18F-fallypride binding potential were predominantly positively correlated across the striatal and extrastriatal grey matter in both healthy and schizophrenia subjects. In comparison to healthy subjects, significantly weaker correlations in subjects with schizophrenia were confirmed in the right cingulate gyrus and thalamus, including the mediodorsal, lateral dorsal, anterior, and midline nuclei. Schizophrenia subjects showed decreased D2/D3-receptor availability in the hypothalamus, mamillary bodies, thalamus and several thalamic nuclei, and increased glucose uptake in three lobules of the cerebellar vermis.Conclusions: Dopaminergic system may be involved in modulation of grey matter metabolism and neurometabolic coupling in both healthy human brain and psychopathology. Hyperdopaminergic state in untreated schizophrenia may at least partly account for the corresponding decreases in grey matter metabolism.


Subject(s)
Fluorodeoxyglucose F18 , Schizophrenia , Benzamides , Dopamine , Fluorine Radioisotopes , Gray Matter/diagnostic imaging , Gray Matter/metabolism , Humans , Positron-Emission Tomography , Receptors, Dopamine D2/metabolism , Receptors, Dopamine D3/metabolism , Schizophrenia/diagnostic imaging
5.
Brain Imaging Behav ; 14(3): 736-752, 2020 Jun.
Article in English | MEDLINE | ID: mdl-30523488

ABSTRACT

Dopaminergic dysfunction and changes in white matter integrity are among the most replicated findings in schizophrenia. A modulating role of dopamine in myelin formation has been proposed in animal models and healthy human brain, but has not yet been systematically explored in schizophrenia. We used diffusion tensor imaging and 18F-fallypride positron emission tomography in 19 healthy and 25 schizophrenia subjects to assess the relationship between gray matter dopamine D2/D3 receptor density and white matter fractional anisotropy in each diagnostic group. AFNI regions of interest were acquired for 42 cortical Brodmann areas and subcortical gray matter structures as well as stereotaxically placed in representative white matter areas implicated in schizophrenia neuroimaging literature. Welch's t-test with permutation-based p value adjustment was used to compare means of z-transformed correlations between fractional anisotropy and 18F-fallypride binding potentials in hypothesis-driven regions of interest in the diagnostic groups. Healthy subjects displayed an extensive pattern of predominantly negative correlations between 18F-fallypride binding across a range of cortical and subcortical gray matter regions and fractional anisotropy in rostral white matter regions (internal capsule, frontal lobe, anterior corpus callosum). These patterns were disrupted in subjects with schizophrenia, who displayed significantly weaker overall correlations as well as comparatively scant numbers of significant correlations with the internal capsule and frontal (but not temporal) white matter, especially for dopamine receptor density in thalamic nuclei. Dopamine D2/D3 receptor density and white matter integrity appear to be interrelated, and their decreases in schizophrenia may stem from hyperdopaminergia with dysregulation of dopaminergic impact on axonal myelination.


Subject(s)
Schizophrenia , Animals , Anisotropy , Benzamides , Brain/diagnostic imaging , Diffusion Tensor Imaging , Dopamine , Humans , Magnetic Resonance Imaging , Positron-Emission Tomography , Schizophrenia/diagnostic imaging
6.
Innov Clin Neurosci ; 16(3-4): 11-15, 2019 Mar 01.
Article in English | MEDLINE | ID: mdl-31214477

ABSTRACT

Substance use disorders are widespread and cause significant dysfunction. Substance use disorders often co-occur with other psychiatric disorders. Because of this overlap, clinicians commonly encounter patients at risk for substance abuse disorders. This article reviews strategies to aid the practicing clinician in the screening, assessment, intervention, and referral of their parents at risk for substance use disorders.

7.
J Clin Med ; 7(2)2018 Jan 30.
Article in English | MEDLINE | ID: mdl-29385731

ABSTRACT

Benzodiazepines are some of the most commonly prescribed medications in the world. These sedative-hypnotics can provide rapid relief for symptoms like anxiety and insomnia, but are also linked to a variety of adverse effects (whether used long-term, short-term, or as needed). Many patients take benzodiazepines long-term without ever receiving evidence-based first-line treatments (e.g., psychotherapy, relaxation techniques, sleep hygiene education, serotonergic agents). This review discusses the risks and benefits of, and alternatives to benzodiazepines. We discuss evidence-based indications and contraindications, and the theoretical biopsychosocial bases for effectiveness, ineffectiveness and harm. Potential adverse effects and drug-drug interactions are summarized. Finally, both fast-acting/acute and delayed-action/chronic alternative treatments for anxiety and/or insomnia are discussed. Response to treatment-whether benzodiazepines, other pharmacological agents, or psychotherapy-should be determined based on functional recovery and not merely sedation.

8.
J Clin Med ; 7(2)2018 Jan 30.
Article in English | MEDLINE | ID: mdl-29385766

ABSTRACT

This review discusses risks, benefits, and alternatives in patients already taking benzodiazepines when care transfers to a new clinician. Prescribers have the decision-sometimes mutually agreed-upon and sometimes unilateral-to continue, discontinue, or change treatment. This decision should be made based on evidence-based indications (conditions and timeframes), comorbidities, potential drug-drug interactions, and evidence of adverse effects, misuse, abuse, dependence, or diversion. We discuss management tools involved in continuation (e.g., monitoring symptoms, laboratory testing, prescribing contracts, state prescription databases, stages of change) and discontinuation (e.g., tapering, psychotherapeutic interventions, education, handouts, reassurance, medications to assist with discontinuation, and alternative treatments).

9.
J Telemed Telecare ; 24(6): 434-439, 2018 Jul.
Article in English | MEDLINE | ID: mdl-28474972

ABSTRACT

Individuals with intellectual disability experience higher rates of mental illness when compared with the general population, and there is a lack of medical and mental health professionals in rural and under-served areas. With the increase in discharge of individuals from institutional settings back to their home communities into the least restrictive environments, there are more patients with complex needs being added to the schedules of physicians in the outpatient delivery care system. Patients with disabilities may not travel well or tolerate changes in routine so may not have access to psychiatry. Utilization of telepsychiatry is well suited to this specialized patient population because it allows a highly traumatized group to meet with a psychiatrist and other mental health professionals from a location of their choice. Ohio's Telepsychiatry Project for Intellectual Disability was initiated in 2012 to serve outlying communities with a lack of infrastructure and resources, to provide specialized mental health services to individuals with co-occurring mental illness and intellectual disability. After five years, over 900 patients with intellectual disability from 64 of Ohio's 88 counties receive specialized mental health treatment through this statewide grant-funded project.


Subject(s)
Health Services Accessibility/economics , Health Services Accessibility/organization & administration , Intellectual Disability , Psychiatry , Rural Population , Telemedicine , Ambulatory Care , Cost-Benefit Analysis , Humans , Intellectual Disability/therapy , Mental Health Services , Ohio
10.
Schizophr Res ; 192: 442-456, 2018 02.
Article in English | MEDLINE | ID: mdl-28576546

ABSTRACT

Converging evidence indicates that the prefrontal cortex is critically involved in executive control and that executive dysfunction is implicated in schizophrenia. Reduced dopamine D2/D3 receptor binding potential has been reported in schizophrenia, and the correlations with neuropsychological test scores have been positive and negative for different tasks. The aim of this study was to examine the relation between dopamine D2/D3 receptor levels with frontal and temporal neurocognitive performance in schizophrenia. Resting-state 18F-fallypride positron emission tomography was performed on 20 medication-naïve and 5 previously medicated for brief earlier periods patients with schizophrenia and 19 age- and sex-matched healthy volunteers. Striatal and extra-striatal dopamine D2/D3 receptor levels were quantified as binding potential using fallypride imaging. Magnetic resonance images in standard Talairach position and segmented into gray and white matter were co-registered to the fallypride images, and the AFNI stereotaxic atlas was applied. Two neuropsychological tasks known to activate frontal and temporal lobe function were chosen, specifically the Wisconsin Card Sorting Test (WCST) and the California Verbal Learning Test (CVLT). Images of the correlation coefficient between fallypride binding and WCST and CVLT performance showed a negative correlation in contrast to positive correlations in healthy volunteers. The results of this study demonstrate that lower fallypride binding potential in patients with schizophrenia may be associated with better performance. Our findings are consistent with previous studies that failed to find cognitive improvements with typical dopamine-blocking medications.


Subject(s)
Brain/metabolism , Executive Function , Receptors, Dopamine D2/metabolism , Receptors, Dopamine D3/metabolism , Schizophrenia/metabolism , Schizophrenic Psychology , Adult , Benzamides , Brain/diagnostic imaging , Executive Function/physiology , Female , Fluorine Radioisotopes , Humans , Male , Neuropsychological Tests , Positron-Emission Tomography , Radiopharmaceuticals , Rest , Schizophrenia/diagnostic imaging
11.
Schizophr Res ; 122(1-3): 43-52, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20655709

ABSTRACT

BACKGROUND: Molecular imaging of dopaminergic parameters has contributed to the dopamine hypothesis of schizophrenia, expanding our understanding of pathophysiology, clinical phenomenology and treatment. Our aim in this study was to compare (18)F-fallypride binding potential BP(ND) in a group of patients with schizophrenia-spectrum illness vs. controls, with a particular focus on the cortex and thalamus. METHODS: We acquired (18)F-fallypride positron emission tomography images on 33 patients with schizophrenia spectrum disorder (28 with schizophrenia; 5 with schizoaffective disorder) and 18 normal controls. Twenty-four patients were absolutely neuroleptic naïve and nine were previously medicated, although only four had a lifetime neuroleptic exposure of greater than two weeks. Parametric images of (18)F-fallypride BP(ND) were calculated to compare binding across subjects. RESULTS: Decreased BP(ND) was observed in the medial dorsal nucleus of the thalamus, prefrontal cortex, lateral temporal lobe and primary auditory cortex. These findings were most marked in subjects who had never previously received medication. CONCLUSIONS: The regions with decreased BP(ND) tend to match brain regions previously reported to show alterations in metabolic activity and blood flow and areas associated with the symptoms of schizophrenia.


Subject(s)
Benzamides , Fluorine Radioisotopes , Pyrrolidines , Schizophrenia/diagnostic imaging , Adolescent , Adult , Analysis of Variance , Benzamides/metabolism , Brain/diagnostic imaging , Brain Mapping , Case-Control Studies , Female , Humans , Magnetic Resonance Imaging , Male , Positron-Emission Tomography/methods , Protein Binding/drug effects , Pyrrolidines/metabolism , Schizophrenia/pathology , Statistics as Topic , Young Adult
SELECTION OF CITATIONS
SEARCH DETAIL
...