RESUMO
Effective suicide prevention is hindered by a limited understanding of the natural progression and neurobiology of the suicidal process. Our objective was to characterize the duration of the suicidal process and its relation to possible determinants: time judgment and cognitive impulsivity. In four groups of adults of both sexes including recent suicide attempters (nâ¯=â¯57), suicidal ideators (nâ¯=â¯131), non-suicidal depressed controls (nâ¯=â¯51) and healthy controls (nâ¯=â¯48) we examined time estimation and production, impulsivity and other cognitive variables. Duration of the suicidal process was recorded in suicide attempters. The suicide process duration, suicide contemplation and action intervals, had a bimodal distribution, â¼40% of attempters took less than 5 min from decision to attempt. Time slowing correlated negatively with the suicidal action interval (time from the decision to kill oneself to suicide attempt) (pâ¯=â¯.003). Individuals with suicide contemplation interval shorter than three hours showed increased time slowing, measured as shorter time production at 35 s (pâ¯=â¯.011) and 43 s (pâ¯=â¯.036). Delay discounting for rewards correlated with time estimation at 25 min (pâ¯=â¯.02) and 90 s (pâ¯=â¯.01). Time slowing correlated positively with suicidal ideation severity, independently of depression severity (pâ¯<â¯.001). Perception of time slowing may influence both the intensity and the duration of the suicidal process. Time slowing may initially be triggered by intense psychological pain, then worsen the perception of inescapability in suicidal patients.
Assuntos
Depressão/psicologia , Ideação Suicida , Tentativa de Suicídio/psicologia , Percepção do Tempo/fisiologia , Adulto , Estudos Transversais , Depressão/diagnóstico , Feminino , Humanos , Comportamento Impulsivo/fisiologia , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
PURPOSE/BACKGROUND: In addition to clozapine, other atypical antipsychotic drugs pharmacologically similar to clozapine, for example, olanzapine, risperidone, and melperone, are also effective in a similar proportion of treatment-resistant schizophrenia (TRS) patients, ~40%. The major goal of this study was to compare 2 doses of lurasidone, another atypical antipsychotic drug, and time to improvement in psychopathology and cognition during a 6-month trial in TRS patients. METHODS/PROCEDURES: The diagnosis of TRS was based on clinical history and lack of improvement in psychopathology during a 6-week open trial of lurasidone 80 mg/d (phase 1). This was followed by a randomized, double-blind, 24-week trial of lurasidone, comparing 80- and 240-mg/d doses (phase 2). FINDINGS/RESULTS: Significant non-dose-related improvement in the Positive and Negative Syndrome Scale-Total and subscales and in 2 of 7 cognitive domains, speed of processing and executive function, were noted. Twenty-eight (41.8%) of 67 patients in the combined sample improved ≥20% in the Positive and Negative Syndrome Scale-Total. Of the 28 responders, 19 (67.9%) first reached ≥20% improvement between weeks 6 and 24 during phase 2, including some who had previously failed to respond to clozapine. IMPLICATIONS/CONCLUSIONS: Improvement with lurasidone is comparable with those previously reported for clozapine, melperone, olanzapine, and risperidone in TRS patients. In addition, this study demonstrated that 80 mg/d lurasidone, an effective and tolerable dose for non-TRS patients, was also effective in TRS patients but required longer duration of treatment. Direct comparison of lurasidone with clozapine in TRS patients is indicated.
Assuntos
Resistência a Medicamentos/efeitos dos fármacos , Cloridrato de Lurasidona/uso terapêutico , Esquizofrenia/tratamento farmacológico , Psicologia do Esquizofrênico , Adulto , Antipsicóticos/efeitos adversos , Antipsicóticos/uso terapêutico , Método Duplo-Cego , Feminino , Humanos , Cloridrato de Lurasidona/efeitos adversos , Masculino , Escalas de Graduação Psiquiátrica , Resultado do TratamentoRESUMO
Constantly shifting cultural views influence public perceptions of psychiatric diagnoses, sometimes accommodated by changes in diagnostic terminology. Evolving scientific knowledge of the era is at times used to justify and support mental illnesses. Too often, however, remasked nomenclatures fail to alter social stigma, in part because political arguments are used. Scientific validations of variant behaviors as symptoms with a pathologic status are unfortunately overshadowed. Examples of cultural bias effects on recurring diagnostic challenges illustrate a need for scientific validation. Renaming fails to improve stigma or diagnostic clarity. For example, neurasthenia, or nervous exhaustion, was attributed to fast-paced urban life through the late 1970s. Its symptoms are now largely, to no real advantage, retitled as chronic fatigue syndrome. Diagnoses like "hysteria" have evolved into histrionic personality disorder and somatoform spectrum disorders, although less as a result of demonic possession or a "wandering uterus." Decriminalized and depathologized homosexuality remains a political football, where religious "sin" conceptualizations have not been displaced by studies documenting healthy adjustments among groups with diverse sexual orientations and preferences. Each of these remains severely socially stigmatized. The pseudoscience of "drapetomania," once used to rationalize and pathologize a slave's freedom, is perceived now as psychiatric incarcerations of mentally healthy individuals, more commonly in totalitarian regimes-a politicization of stigma. Research reviews and funding efforts need to emphasize a sound basis for individuals caught in perpetuated diagnostic challenges, not remedied by simple shifts in nomenclature.
Assuntos
Transtornos Mentais/história , Psiquiatria/história , Terminologia como Assunto , História do Século XIX , História do Século XX , HumanosRESUMO
Defects in experiencing disgust may contribute to obesity by allowing for the overconsumption of food. However, the relationship of disgust proneness and its associated neural locus has yet to be explored in the context of obesity. Thirty-three participants (17 obese, 16 lean) completed the Disgust Propensity and Sensitivity Scale-Revised and a functional magnetic resonance imaging paradigm where images from 4 categories (food, contaminates, contaminated food or fixation) were randomly presented. Independent two-sample t-tests revealed significantly lower levels of Disgust Sensitivity for the obese group (mean score = 14.7) compared with the lean group (mean score = 17.6, P = 0.026). The obese group had less activation in the right insula than the lean group when viewing contaminated food images. Multiple regression with interaction analysis revealed one left insula region where the association of Disgust Sensitivity scores with activation differed by group when viewing contaminated food images. These interaction effects were driven by the negative correlation of Disgust Sensitivity scores with beta values extracted from the left insula in the obese group (r = -0.59) compared with a positive correlation in the lean group (r = 0.65). Given these body mass index-dependent differences in Disgust Sensitivity and neural responsiveness to disgusting food images, it is likely that altered Disgust Sensitivity may contribute to obesity.
Assuntos
Emoções , Obesidade/psicologia , Adulto , Índice de Massa Corporal , Mapeamento Encefálico , Córtex Cerebral , Ingestão de Alimentos , Feminino , Alimentos , Contaminação de Alimentos , Lateralidade Funcional , Humanos , Fome , Hiperfagia/psicologia , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Estimulação LuminosaRESUMO
Depression remains a great societal burden and a major treatment challenge. Most antidepressant medications target serotonergic raphé nuclei. Acute tryptophan depletion (ATD) modulates serotonin function. To better understand the raphé's role in mood networks, we studied raphé functional connectivity in depression. Fifteen depressed patients were treated with sertraline for 12 weeks and scanned during ATD and sham conditions. Based on our previous findings in a separate cohort, resting state MRI functional connectivity between raphé and other depression-related regions (ROIs) was analyzed in narrow frequency bands. ATD decreased raphé functional connectivity with the bilateral thalamus within 0.025-0.05 Hz, and also decreased raphé functional connectivity with the right pregenual anterior cingulate cortex within 0.05-0.1 Hz. Using the control broadband filter 0.01-0.1 Hz, no significant differences in raphé-ROI functional connectivity were observed. Post-hoc analysis by remission status suggested increased raphé functional connectivity with left pregenual anterior cingulate cortex in remitters (n=10) and decreased raphé functional connectivity with left thalamus in non-remitters (n=5), both within 0.025-0.05 Hz. Reducing serotonin function appears to alter coordination of these mood-related networks in specific, low frequency ranges. For examination of effects of reduced serotonin function on mood-related networks, specific low frequency BOLD fMRI signals can identify regions implicated in neural circuitry and may enable clinically-relevant interpretation of functional connectivity measures. The biological significance of these low frequency signals detected in the raphé merits further study.
Assuntos
Transtorno Depressivo Maior/sangue , Transtorno Depressivo Maior/dietoterapia , Rede Nervosa/metabolismo , Núcleos da Rafe/metabolismo , Triptofano/deficiência , Adulto , Transtorno Depressivo Maior/diagnóstico , Feminino , Giro do Cíngulo/metabolismo , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Tálamo/metabolismo , Triptofano/antagonistas & inibidoresRESUMO
BACKGROUND: Deep brain stimulation (DBS) is an effective treatment for patients with advanced Parkinson's disease (PD) and motor symptom complications. Recently, attention has been focused on whether offering DBS earlier in the course of PD is beneficial. OBJECTIVE: The purpose of this study was to determine the effects of DBS on neuropsychological functioning in subjects with early stage PD. METHODS: Thirty subjects with early PD (Hoehn & Yahr Stage II off medication) were randomized to optimal drug therapy (ODT) (n = 15) or bilateral subthalamic nucleus (STN) DBS+ODT (n = 15) after completing an expanded informed consent process specially designed for the study and administered by a medical ethicist and the study team. Comprehensive neuropsychological testing was completed in the treatment-withdrawn state at baseline and at 12 month and 24 month follow-ups. RESULTS: Two serious adverse events occurred in the DBS+ODT group. One subject experienced a stroke and another developed infected hardware that contributed to specific declines in cognitive functioning. However, compared to the ODT group, the remaining subjects in the DBS+ODT group exhibited modest reductions on a few measures of attention, executive function, and word fluency at 12 months. These differences were largely diminished at 24 months, especially when those with the adverse events were excluded. CONCLUSIONS: The results of this trial provide novel data regarding the effects of DBS on cognitive function in early PD. We believe that the findings and insights from this trial can help guide the safety analysis and risk-benefit evaluations in future discussions of DBS in early stage PD.
Assuntos
Transtornos Cognitivos/etiologia , Transtornos Cognitivos/terapia , Estimulação Encefálica Profunda/métodos , Doença de Parkinson/complicações , Núcleo Subtalâmico/fisiologia , Idoso , Antiparkinsonianos/uso terapêutico , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Doença de Parkinson/terapia , Índice de Gravidade de Doença , Núcleo Subtalâmico/efeitos dos fármacos , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Deep brain stimulation (DBS) is an effective and approved therapy for advanced Parkinson's disease (PD), and a recent study suggests efficacy in mid-stage disease. This manuscript reports the results of a pilot trial investigating preliminary safety and tolerability of DBS in early PD. METHODS: Thirty subjects with idiopathic PD (Hoehn & Yahr Stage II off medication), age 50-75, on medication ≥6 months but ≤4 years, and without motor fluctuations or dyskinesias were randomized to optimal drug therapy (ODT) (n = 15) or DBS + ODT (n = 15). Co-primary endpoints were the time to reach a 4-point worsening from baseline in the UPDRS-III off therapy and the change in levodopa equivalent daily dose from baseline to 24 months. RESULTS: As hypothesized, the mean UPDRS total and part III scores were not significantly different on or off therapy at 24 months. Medication requirements in the DBS + ODT group were lower at all time points with a maximal difference at 18 months. With a few exceptions, differences in neuropsychological functioning were not significant. Two subjects in the DBS + ODT group suffered serious adverse events; remaining adverse events were mild or transient. CONCLUSIONS: This study demonstrates that subjects with early stage PD will enroll in and complete trials testing invasive therapies and provides preliminary evidence that DBS is well tolerated in early PD. The results of this trial provide the data necessary to design a large, phase III, double-blind, multicenter trial investigating the safety and efficacy of DBS in early PD.
Assuntos
Estimulação Encefálica Profunda/métodos , Doença de Parkinson/diagnóstico , Doença de Parkinson/terapia , Núcleo Subtalâmico/fisiologia , Idoso , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Doença de Parkinson/fisiopatologia , Projetos Piloto , Estudos Prospectivos , Método Simples-CegoRESUMO
Oscillations in brain activities with periods of minutes to hours may be critical for normal mood behaviors. Ultradian (faster than circadian) rhythms of mood behaviors and associated central nervous system activities are altered in depression. Recent data suggest that ultradian rhythms in serotonin (5HT) function also change in depression. In two separate studies, 5HT metabolites in cerebrospinal fluid (CSF) were measured every 10 min for 24 h before and after chronic antidepressant treatment. Antidepressant treatments were associated with enhanced ultradian amplitudes of CSF metabolite levels. Another study used resting-state functional magnetic resonance imaging (fMRI) to measure amplitudes of dorsal raphé activation cycles following sham or active dietary depletions of the 5HT precursor (tryptophan). During depletion, amplitudes of dorsal raphé activation cycles increased with rapid 6 s periods (about 0.18 Hz) while functional connectivity weakened between dorsal raphé and thalamus at slower periods of 20 s (0.05 Hz). A third approach studied MDMA (ecstasy, 3,4-methylenedioxy-N-methylamphetamine) users because of their chronically diminished 5HT function compared with non-MDMA polysubstance users (Karageorgiou et al., 2009). Compared with a non-MDMA using cohort, MDMA users showed diminished fMRI intra-regional coherence in motor regions along with altered functional connectivity, again suggesting effects of altered 5HT oscillatory function. These data support a hypothesis that qualities of ultradian oscillations in 5HT function may critically influence moods and behaviors. Dysfunctional 5HT rhythms in depression may be a common endpoint and biomarker for depression, linking dysfunction of slow brain network oscillators to 5HT mechanisms affected by commonly available treatments. 5HT oscillatory dysfunction may define illness subtypes and predict responses to serotonergic agents. Further studies of 5HT oscillations in depression are indicated.
Assuntos
Ritmo Circadiano , Transtorno Depressivo/metabolismo , Serotonina/metabolismo , Transtorno Depressivo/tratamento farmacológico , Transtorno Depressivo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética/métodos , Núcleos da Rafe/metabolismo , Núcleos da Rafe/fisiopatologia , Serotonina/líquido cefalorraquidiano , Serotoninérgicos/uso terapêuticoRESUMO
RATIONALE: Ecstasy (3,4-methylenedioxymethamphetamine [MDMA]) polydrug users have verbal memory performance that is statistically significantly lower than that of control subjects. Studies have correlated long-term MDMA use with altered brain activation in regions that play a role in verbal memory. OBJECTIVES: The aim of our study was to examine the association of lifetime ecstasy use with semantic memory performance and brain activation in ecstasy polydrug users. METHODS: A total of 23 abstinent ecstasy polydrug users (age = 24.57 years) and 11 controls (age = 22.36 years) performed a two-part functional magnetic resonance imaging (fMRI) semantic encoding and recognition task. To isolate brain regions activated during each semantic task, we created statistical activation maps in which brain activation was greater for word stimuli than for non-word stimuli (corrected p < 0.05). RESULTS: During the encoding phase, ecstasy polydrug users had greater activation during semantic encoding bilaterally in language processing regions, including Brodmann areas 7, 39, and 40. Of this bilateral activation, signal intensity with a peak T in the right superior parietal lobe was correlated with lifetime ecstasy use (r s = 0.43, p = 0.042). Behavioral performance did not differ between groups. CONCLUSIONS: These findings demonstrate that ecstasy polydrug users have increased brain activation during semantic processing. This increase in brain activation in the absence of behavioral deficits suggests that ecstasy polydrug users have reduced cortical efficiency during semantic encoding, possibly secondary to MDMA-induced 5-HT neurotoxicity. Although pre-existing differences cannot be ruled out, this suggests the possibility of a compensatory mechanism allowing ecstasy polydrug users to perform equivalently to controls, providing additional support for an association of altered cerebral neurophysiology with MDMA exposure.
Assuntos
Encéfalo/efeitos dos fármacos , Drogas Ilícitas/efeitos adversos , Memória/efeitos dos fármacos , N-Metil-3,4-Metilenodioxianfetamina/efeitos adversos , Desempenho Psicomotor/efeitos dos fármacos , Semântica , Adolescente , Adulto , Encéfalo/metabolismo , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Memória/fisiologia , N-Metil-3,4-Metilenodioxianfetamina/administração & dosagem , Estudos Prospectivos , Desempenho Psicomotor/fisiologia , Adulto JovemRESUMO
Oxidative stress may play a role in the pathogenesis of depression. We tested the hypothesis that urinary F2 isoprostanes, a robust marker of oxidative stress, was increased in patients with depression and associated with symptoms and response to treatment. Urinary F2 isoprostanes was compared in 18 patients with depression and 36 age and sex matched control subjects. In patients, we tested the association between oxidative stress, depression questionnaires and antidepressant treatment. Urinary F2 isoprostane excretion was significantly higher in patients with depression than in control subjects. This association remained significant after adjustment for age, sex and BMI. Depression symptom severity scores were not correlated with F2 isoprostane excretion. Nine patients were treated with sertraline or bupropion for 8 weeks. Depression severity rating scale scores decreased significantly and F2 isoprostane excretion increased. The increase in F2 isoprostane excretion was inversely correlated with the improvement in Hamilton Depression Rating 17 items. In conclusion, oxidative stress is increased in patients with depression. However, although treatment with either bupropion or sertraline reduces the symptoms of depression, it may increase F2 isoprostane excretion. These results suggest that alternative mechanisms, beyond oxidative stress, may be involved in the development of depression and subsequent responses to treatment.
Assuntos
Antidepressivos/uso terapêutico , Transtorno Depressivo Maior/urina , F2-Isoprostanos/urina , Estresse Oxidativo , Adulto , Biomarcadores/urina , Bupropiona/uso terapêutico , Estudos de Casos e Controles , Transtorno Depressivo Maior/tratamento farmacológico , Feminino , Humanos , Masculino , Sertralina/uso terapêutico , Índice de Gravidade de Doença , Adulto JovemRESUMO
BACKGROUND: Deep brain stimulation provides significant symptomatic benefit for people with advanced Parkinson's disease whose symptoms are no longer adequately controlled with medication. Preliminary evidence suggests that subthalamic nucleus stimulation may also be efficacious in early Parkinson's disease, and results of animal studies suggest that it may spare dopaminergic neurons in the substantia nigra. OBJECTIVE: We report the methodology and design of a novel Phase I clinical trial testing the safety and tolerability of deep brain stimulation in early Parkinson's disease and discuss previous failed attempts at neuroprotection. METHODS: We recently conducted a prospective, randomized, parallel-group, single-blind pilot clinical trial of deep brain stimulation in early Parkinson's disease. Subjects were randomized to receive either optimal drug therapy or deep brain stimulation plus optimal drug therapy. Follow-up visits occurred every six months for a period of two years and included week-long therapy washouts. RESULTS: Thirty subjects with Hoehn & Yahr Stage II idiopathic Parkinson's disease were enrolled over a period of 32 months. Twenty-nine subjects completed all follow-up visits; one patient in the optimal drug therapy group withdrew from the study after baseline. Baseline characteristics for all thirty patients were not significantly different. CONCLUSIONS: This study demonstrates that it is possible to recruit and retain subjects in a clinical trial testing deep brain stimulation in early Parkinson's disease. The results of this trial will be used to support the design of a Phase III, multicenter trial investigating the efficacy of deep brain stimulation in early Parkinson's disease.
Assuntos
Estimulação Encefálica Profunda , Doença de Parkinson/terapia , Projetos de Pesquisa , Núcleo Subtalâmico/fisiologia , Idoso , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Projetos Piloto , Método Simples-Cego , Fatores de TempoRESUMO
BACKGROUND: MDMA exposure is associated with chronic serotonergic dysfunction in preclinical and clinical studies. A recent functional magnetic resonance imaging (fMRI) comparison of past MDMA users to non-MDMA-using controls revealed increased spatial extent and amplitude of activation in the supplementary motor area during motor tasks (Karageorgiou et al., 2009). Blood oxygenation level dependent (BOLD) data from that study were reanalyzed for intraregional coherence and for inter-regional temporal correlations between time series, as functional connectivity. METHODS: Fourteen MDMA users and ten controls reporting similar non-MDMA abuse performed finger taps during fMRI. Fourteen motor pathway regions plus a pontine raphé region were examined. Coherence was expressed as percent of voxels positively correlated with an intraregional index voxel. Functional connectivity was determined using wavelet correlations. RESULTS: Intraregional thalamic coherence was significantly diminished at low frequencies in MDMA users compared to controls (p=0.009). Inter-regional functional connectivity was significantly weaker for right thalamo - left caudate (p=0.002), right thalamo - left thalamus (p=0.007), right caudate - right postcentral (p=0.007) and right supplementary motor area - right precentral gyrus (p=0.011) region pairs compared to controls. When stratified by lifetime exposure, significant negative associations were observed between cumulative MDMA use and functional connectivity in seven other region-pairs, while only one region-pair showed a positive association. CONCLUSIONS: Reported prior MDMA use was associated with deficits in BOLD intraregional coherence and inter-regional functional connectivity, even among functionally robust pathways involving motor regions. This suggests that MDMA use is associated with long-lasting effects on brain neurophysiology beyond the cognitive domain.
Assuntos
N-Metil-3,4-Metilenodioxianfetamina/efeitos adversos , Tálamo/efeitos dos fármacos , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Neuroimagem Funcional , Humanos , Imageamento por Ressonância Magnética , Masculino , Córtex Motor/irrigação sanguínea , Córtex Motor/efeitos dos fármacos , Córtex Motor/fisiologia , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/fisiologia , Putamen/irrigação sanguínea , Putamen/efeitos dos fármacos , Putamen/fisiologia , Transtornos Relacionados ao Uso de Substâncias/complicações , Tálamo/irrigação sanguínea , Tálamo/fisiologia , Adulto JovemRESUMO
CONTEXT: MDMA (3,4-methylenedioxymethamphetamine, also popularly known as "ecstasy") is a popular recreational drug that produces loss of serotonin axons in animal models. Whether MDMA produces chronic reductions in serotonin signaling in humans remains controversial. OBJECTIVE: To determine whether MDMA use is associated with chronic reductions in serotonin signaling in the cerebral cortex of women as reflected by increased serotonin(2A) receptor levels. DESIGN: Cross-sectional case-control study comparing serotonin(2A) receptor levels in abstinent female MDMA polydrug users with those in women who did not use MDMA (within-group design assessing the association of lifetime MDMA use and serotonin(2A) receptors). Case participants were abstinent from MDMA use for at least 90 days as verified by analysis of hair samples. The serotonin(2A) receptor levels in the cerebral cortex were determined using serotonin(2A)-specific positron emission tomography with radioligand fluorine 18-labeled setoperone as the tracer. SETTING: Academic medical center research laboratory. PARTICIPANTS: A total of 14 female MDMA users and 10 women who did not use MDMA (controls). The main exclusion criteria were nondrug-related DSM-IV Axis I psychiatric disorders and general medical illness. MAIN OUTCOME MEASURES: Cortical serotonin(2A) receptor nondisplaceable binding potential (serotonin(2A)BP(ND)). RESULTS: MDMA users had increased serotonin(2A)BP(ND) in occipital-parietal (19.7%), temporal (20.5%), occipitotemporal-parietal (18.3%), frontal (16.6%), and frontoparietal (18.5%) regions (corrected P < .05). Lifetime MDMA use was positively associated with serotonin(2A)BP(ND) in frontoparietal (ß = 0.665; P = .007), occipitotemporal (ß = 0.798; P = .002), frontolimbic (ß = 0.634; P = .02), and frontal (ß = 0.691; P = .008) regions. In contrast, there were no regions in which MDMA use was inversely associated with receptor levels. There were no statistically significant effects of the duration of MDMA abstinence on serotonin(2A)BP(ND). CONCLUSIONS: The recreational use of MDMA is associated with long-lasting increases in serotonin(2A) receptor density. Serotonin(2A) receptor levels correlate positively with lifetime MDMA use and do not decrease with abstinence. These results suggest that MDMA use produces chronic serotonin neurotoxicity in humans. Given the broad role of serotonin in human brain function, the possibility for therapeutic MDMA use, and the widespread recreational popularity of this drug, these results have critical public health implications.
Assuntos
Transtornos Relacionados ao Uso de Anfetaminas/metabolismo , Córtex Cerebral/metabolismo , Neuroimagem Funcional/psicologia , N-Metil-3,4-Metilenodioxianfetamina/efeitos adversos , Receptor 5-HT2A de Serotonina/metabolismo , Adolescente , Adulto , Transtornos Relacionados ao Uso de Anfetaminas/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Feminino , Radioisótopos de Flúor , Neuroimagem Funcional/métodos , Humanos , Tomografia por Emissão de Pósitrons/métodos , Tomografia por Emissão de Pósitrons/psicologia , Pirimidinonas , Ensaio Radioligante/métodos , Ensaio Radioligante/psicologia , Antagonistas da Serotonina , Transtornos Relacionados ao Uso de Substâncias/diagnóstico por imagem , Fatores de TempoRESUMO
The serotonergic neurotoxin, 3,4-methylenedioxymethamphetamine (MDMA/Ecstasy), is a highly popular recreational drug. Human recreational MDMA users have neurocognitive and neuropsychiatric impairments, and human neuroimaging data are consistent with animal reports of serotonin neurotoxicity. However, functional neuroimaging studies have not found consistent effects of MDMA on brain neurophysiology in human users. Several lines of evidence suggest that studying MDMA effects in visual system might reveal the general cortical and subcortical neurophysiological consequences of MDMA use. We used 3 T functional magnetic resonance imaging during visual stimulation to compare visual system lateral geniculate nucleus (LGN) and Brodmann Area (BA) 17 and BA 18 activation in 20 long abstinent (479.95±580.65 days) MDMA users and 20 non-MDMA user controls. Lifetime quantity of MDMA use was strongly positively correlated with blood oxygenation level-dependent (BOLD) signal intensity in bilateral LGN (r(s)=0.59; p=0.007), BA 17 (r(s)=0.50; p=0.027), and BA 18 (r(s)=0.48; p=0.031), and with the spatial extent of activation in BA 17 (r(s)=0.059; p=0.007) and BA 18 (r(s)=0.55; p=0.013). There were no between-group differences in brain activation in any region, but the heaviest MDMA users showed a significantly greater spatial extent of activation than controls in BA 17 (p=0.031) and BA 18 (p=0.049). These results suggest that human recreational MDMA use may be associated with a long-lasting increase in cortical excitability, possibly through loss of serotonin input to cortical and subcortical regions. When considered in the context of previous results, cortical hyper-excitability may be a biomarker for MDMA-induced serotonin neurotoxicity.
Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/fisiopatologia , N-Metil-3,4-Metilenodioxianfetamina/efeitos adversos , Serotoninérgicos/efeitos adversos , Vias Visuais/efeitos dos fármacos , Vias Visuais/fisiopatologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Circulação Cerebrovascular/efeitos dos fármacos , Circulação Cerebrovascular/fisiologia , Feminino , Corpos Geniculados/efeitos dos fármacos , Corpos Geniculados/fisiopatologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Córtex Visual/efeitos dos fármacos , Córtex Visual/fisiopatologia , Adulto JovemRESUMO
Serotonin is synthesized from its precursor, tryptophan, by brainstem raphé neurons and their synaptic terminals in limbic regions. The omission of tryptophan from an Acute Tryptophan Depletion (ATD) diet transiently diminishes serotonin synthesis, alters raphé activity, and mimics symptoms of depression. Raphé functional magnetic resonance imaging (fMRI) poses challenges using signal-averaging analyses. Time-series properties of fMRI blood oxygenation level dependent (BOLD) signals may hold promise, so we analyzed raphé signals for changes with the ATD diet. Eleven remitted (previously depressed) patients were awake with eyes-closed during seven-minute resting scans with 0.5s(-1) sampling. BOLD signal time-series data were frequency-filtered using wavelet transforms, yielding three octave-width frequency bands from 0.25 to 0.03s(-1) and an unbounded band below 0.03s(-1). Spectral power, reflecting signal information, increased in pontine raphé at high frequencies (0.25 to 0.125s(-1)) during ATD (compared to control, balanced, diet, P<0.004) but was unchanged at other frequencies. Functional connectivity, the correlation between time-series data from pairs of regions, weakened between pontine raphé and anterior thalamus at low frequencies during ATD (P<0.05). This preliminarily supports using fMRI time-series features to assess pontine raphé function. Whether, and how, high frequency activity oscillations interfere with low frequency signaling requires further study.
Assuntos
Depressão/dietoterapia , Depressão/patologia , Imageamento por Ressonância Magnética , Ponte/irrigação sanguínea , Triptofano/deficiência , Adolescente , Adulto , Estudos Cross-Over , Depressão/fisiopatologia , Dieta , Método Duplo-Cego , Eletroencefalografia/métodos , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Vias Neurais/irrigação sanguínea , Oxigênio/sangue , Estudos Retrospectivos , Estatística como Assunto , Fatores de Tempo , Triptofano/sangue , Análise de Ondaletas , Adulto JovemRESUMO
BACKGROUND: Cerebrospinal fluid (CSF) sodium levels have been reported to rise during episodic migraine. Since migraine frequently starts in early morning or late afternoon, we hypothesized that natural sodium chronobiology may predispose susceptible persons when extracellular CSF sodium increases. Since no mammalian brain sodium rhythms are known, we designed a study of healthy humans to test if cation rhythms exist in CSF. METHODS: Lumbar CSF was collected every ten minutes at 0.1 mL/min for 24 h from six healthy participants. CSF sodium and potassium concentrations were measured by ion chromatography, total protein by fluorescent spectrometry, and osmolarity by freezing point depression. We analyzed cation and protein distributions over the 24 h period and spectral and permutation tests to identify significant rhythms. We applied the False Discovery Rate method to adjust significance levels for multiple tests and Spearman correlations to compare sodium fluctuations with potassium, protein, and osmolarity. RESULTS: The distribution of sodium varied much more than potassium, and there were statistically significant rhythms at 12 and 1.65 h periods. Curve fitting to the average time course of the mean sodium of all six subjects revealed the lowest sodium levels at 03.20 h and highest at 08.00 h, a second nadir at 09.50 h and a second peak at 18.10 h. Sodium levels were not correlated with potassium or protein concentration, or with osmolarity. CONCLUSION: These CSF rhythms are the first reports of sodium chronobiology in the human nervous system. The results are consistent with our hypothesis that rising levels of extracellular sodium may contribute to the timing of migraine onset. The physiological importance of sodium in the nervous system suggests that these rhythms may have additional repercussions on ultradian functions.
RESUMO
OBJECTIVES: Improvements in electronic health record (EHR) system development will require an understanding of psychiatric clinicians' views on EHR system acceptability, including effects on psychotherapy communications, data-recording behaviors, data accessibility versus security and privacy, data quality and clarity, communications with medical colleagues, and stigma. DESIGN: Multidisciplinary development of a survey instrument targeting psychiatric clinicians who recently switched to EHR system use, focus group testing, data analysis, and data reliability testing. MEASUREMENTS: Survey of 120 university-based, outpatient mental health clinicians, with 56 (47%) responding, conducted 18 months after transition from a paper to an EHR system. RESULTS: Factor analysis gave nine item groupings that overlapped strongly with five a priori domains. Respondents both praised and criticized the EHR system. A strong majority (81%) felt that open therapeutic communications were preserved. Regarding data quality, content, and privacy, clinicians (63%) were less willing to record highly confidential information and disagreed (83%) with including their own psychiatric records among routinely accessed EHR systems. LIMITATIONS: single time point; single academic medical center clinic setting; modest sample size; lack of prior instrument validation; survey conducted in 2005. CONCLUSIONS: In an academic medical center clinic, the presence of electronic records was not seen as a dramatic impediment to therapeutic communications. Concerns regarding privacy and data security were significant, and may contribute to reluctances to adopt electronic records in other settings. Further study of clinicians' views and use patterns may be helpful in guiding development and deployment of electronic records systems.
Assuntos
Atitude Frente a Saúde , Revelação , Registros Eletrônicos de Saúde , Transtornos Mentais/terapia , Padrões de Prática Médica , Adulto , Segurança Computacional , Confidencialidade , Feminino , Pesquisas sobre Atenção à Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Psiquiatria , Processos Psicoterapêuticos , TennesseeRESUMO
MDMA (3,4-methylenedioxymethamphetamine; Ecstasy) is a popular recreational drug that produces long-lasting serotonin (5-HT) neurotoxicity consisting of reductions in markers for 5-HT axons. 5-HT innervates cortical and subcortical brain regions mediating motor function, predicting that MDMA users will have altered motor system neurophysiology. We used functional magnetic resonance imaging (fMRI) to assay motor task performance-associated brain activation changes in MDMA and non-MDMA users. 24 subjects (14 MDMA users and 10 controls) performed an event-related motor tapping task (1, 2 or 4 taps) during fMRI at 3 T. Motor regions of interest were used to measure percent signal change (PSC) and percent activated voxels (PAV) in bilateral motor cortex, sensory cortex, supplementary motor area (SMA), caudate, putamen, pallidum and thalamus. We used SPM5 to measure brain activation via three methods: T-maps, PSC and PAV. There was no statistically significant difference in reaction time between the two groups. For the Tap 4 condition, MDMA users had more activation than controls in the right SMA for T-score (p=0.02), PSC (p=0.04) and PAV (p=0.03). Lifetime episodes of MDMA use were positively correlated with PSC for the Tap 4 condition on the right for putamen and pallidum; with PAV in the right motor and sensory cortex and bilateral thalamus. In conclusion, we found a group difference in the right SMA and positive dose-response association between lifetime exposure to MDMA and signal magnitude and extent in several brain regions. This evidence is consistent with MDMA-induced alterations in basal ganglia-thalamocortical circuit neurophysiology and is potentially secondary to neurotoxic effects on 5-HT signaling. Further studies examining behavioral correlates and the specific neurophysiological basis of the observed findings are warranted.
Assuntos
Gânglios da Base/fisiopatologia , Córtex Cerebral/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Movimento/efeitos dos fármacos , N-Metil-3,4-Metilenodioxianfetamina/toxicidade , Análise e Desempenho de Tarefas , Tálamo/fisiopatologia , Adolescente , Adulto , Gânglios da Base/efeitos dos fármacos , Córtex Cerebral/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Humanos , Masculino , Tálamo/efeitos dos fármacos , Adulto JovemRESUMO
Treatment-related changes in neurobiological rhythms are of increasing interest to psychologists, psychiatrists, and biological rhythms researchers. New methods for analyzing change in rhythms are needed, as most common methods disregard the rich complexity of biological processes. Large time series data sets reflect the intricacies of underlying neurobiological processes, but can be difficult to analyze. We propose the use of Fourier methods with multivariate permutation test (MPT) methods for analyzing change in rhythms from time series data. To validate the use of MPT for Fourier-transformed data, we performed Monte Carlo simulations and compared statistical power and family-wise error for MPT to Bonferroni-corrected and uncorrected methods. Results show that MPT provides greater statistical power than Bonferroni-corrected tests, while appropriately controlling family-wise error. We applied this method to human, pre- and post-treatment, serially-sampled neurotransmitter data to confirm the utility of this method using real data. Together, Fourier with MPT methods provides a statistically powerful approach for detecting change in biological rhythms from time series data.