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1.
Front Psychiatry ; 12: 735523, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34744825

RESUMO

Background: Anorexia nervosa (AN) is a serious and life-threatening psychiatric condition. With a paucity of approved treatments, there is a desperate need for novel treatment avenues to be explored. Here, we present (1) an overview of the ways through which Public Patient Involvement (PPI) has informed a trial of psilocybin-assisted therapy for AN and (2) a protocol for a pilot study of psilocybin-assisted therapy in AN currently underway at Imperial College London. The study aims to assess the feasibility, brain mechanisms and preliminary outcomes of treating anorexia nervosa with psilocybin. Methods: (1) PPI: Across two online focus groups, eleven individuals with lived experience of AN were presented with an overview of the protocol. Their feedback not only identified solutions to possible barriers for future participants, but also helped the research team to better understand the concept of "recovery" from the perspective of those with lived experience. (2) Protocol: Twenty female participants [21-65 years old, body mass index (BMI) 15 kg/m2 or above] will receive three oral doses of psilocybin (up to 25 mg) over a 6-week period delivered in a therapeutic environment and enveloped by psychological preparation and integration. We will work with participant support networks (care teams and an identified support person) throughout and there will be an extended remote follow-up period of 12 months. Our two-fold primary outcomes are (1) psychopathology (Eating Disorder Examination) across the 6-month follow-up and (2) readiness and motivation to engage in recovery (Readiness and Motivation Questionnaire) across the 6-week trial period. Neurophysiological outcome measures will be: (1) functional magnetic resonance imaging (fMRI) brain changes from baseline to 6-week endpoint and (2) post-acute changes in electroencephalography (EEG) activity, including an electrophysiological marker of neuronal plasticity. Discussion: The results of this pilot study will not only shed light on the acceptability, brain mechanisms, and impression of the potential efficacy of psilocybin as an adjunct treatment for AN but will be essential in shaping a subsequent Randomised Control Trial (RCT) that would test this treatment against a suitable control condition. Clinical Trial Registration: identifier: NCT04505189.

2.
J Psychopharmacol ; 35(4): 375-383, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33601929

RESUMO

BACKGROUND: 3,4-methylenedioxymethamphetamine (MDMA) therapy has qualities that make it potentially well suited for patients with addictions, but this has never been explored in a research study. We present data from the Bristol Imperial MDMA in Alcoholism (BIMA) study. This is the first MDMA addiction study, an open-label safety and tolerability proof-of-concept study investigating the potential role for MDMA therapy in treating patients with alcohol use disorder (AUD). AIMS: This study aimed to assess if MDMA-assisted psychotherapy can be delivered safely and can be tolerated by patients with AUD post detoxification. Outcomes regarding drinking behaviour, quality of life and psychosocial functioning were evaluated. METHODS: Fourteen patients with AUD completed a community alcohol detoxification and received an eight-week course of recovery-based therapy. Participants received two sessions with MDMA (187.5 mg each session). Psychological support was provided before, during and after each session. Safety and tolerability were assessed alongside psychological and physiological outcome measures. Alcohol use behaviour, mental well-being and functioning data were collected for nine months after alcohol detoxification. RESULTS: MDMA treatment was well tolerated by all participants. No unexpected adverse events were observed. Psychosocial functioning improved across the cohort. Regarding alcohol use, at nine months post detox, the average units of alcohol consumption by participants was 18.7 units per week compared to 130.6 units per week before the detox. This compares favourably to a previous observational study (the 'Outcomes' study) by the same team with a similar population of people with AUD. CONCLUSIONS: This study provides preliminary support for the safety and tolerability of a novel intervention for AUD post detox. Further trials to examine better the therapeutic potential of this approach are now indicated.


Assuntos
Alcoolismo , N-Metil-3,4-Metilenodioxianfetamina , Funcionamento Psicossocial , Psicoterapia/métodos , Qualidade de Vida , Consumo de Bebidas Alcoólicas/psicologia , Consumo de Bebidas Alcoólicas/terapia , Alcoolismo/diagnóstico , Alcoolismo/fisiopatologia , Alcoolismo/psicologia , Alcoolismo/terapia , Terapia Combinada , Monitoramento de Medicamentos/métodos , Feminino , Alucinógenos/administração & dosagem , Alucinógenos/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , N-Metil-3,4-Metilenodioxianfetamina/administração & dosagem , N-Metil-3,4-Metilenodioxianfetamina/efeitos adversos , Avaliação de Resultados em Cuidados de Saúde , Estudo de Prova de Conceito , Escalas de Graduação Psiquiátrica , Recuperação de Função Fisiológica , Resultado do Tratamento , Reino Unido
3.
J Psychopharmacol ; 35(5): 547-555, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-32538252

RESUMO

BACKGROUND: 3,4-Methylenedioxymethamphetamine (MDMA) is being actively researched as an adjunct to psychotherapy. It may be beneficial to trust, empathy and cooperative behaviour due to its acute prosocial effects. AIM: To test (a) the acute effects of MDMA on measures of empathy, trust and cooperative behaviour, and (b) subacute changes in mood three days after MDMA administration. METHODS: Twenty-five participants (n=7 female), participated in this double-blind, repeated-measures, placebo-controlled experiment. Participants attended two acute sessions, one week apart. Each acute session was followed by a subacute session three days later. Participants received placebo (100 mg ascorbic acid) during one acute session, and MDMA (100 mg MDMA-HCl) at the other, with order counterbalanced. Participants completed the following tasks assessing prosocial behaviour: a trust investment task, a trustworthy face rating task, an empathic stories task, a public project game, a dictator game and an ultimatum game. Participants reported subjective effects. Blood was taken pre-drug, 2 and 4 hours post-drug, and tested for plasma MDMA levels. RESULTS: MDMA acutely increased self-reported 'closeness to others' and 'euphoria' and increased plasma concentrations of MDMA. MDMA did not significantly change task-based empathy, trust or cooperative behaviour. Using Bayesian analyses, we found evidence that MDMA and placebo did not differ in their effects on empathy and cooperative behaviour. MDMA did not significantly change subacute mood and this was supported by our Bayesian analyses. CONCLUSION: Despite augmentation in plasma MDMA levels and subjective drug effects, we found no increase in prosocial behaviour in a laboratory setting.


Assuntos
Afeto/efeitos dos fármacos , Empatia/efeitos dos fármacos , N-Metil-3,4-Metilenodioxianfetamina/farmacologia , Confiança/psicologia , Adulto , Teorema de Bayes , Comportamento Cooperativo , Método Duplo-Cego , Feminino , Alucinógenos/sangue , Alucinógenos/farmacologia , Humanos , Masculino , Pessoa de Meia-Idade , N-Metil-3,4-Metilenodioxianfetamina/sangue , Comportamento Social , Adulto Jovem
4.
Psychopharmacology (Berl) ; 237(3): 841-853, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31853557

RESUMO

Research has shown that psychedelics, such as lysergic acid diethylamide (LSD), have profound anti-inflammatory properties mediated by 5-HT2A receptor signaling, supporting their evaluation as a therapeutic for neuroinflammation associated with neurodegenerative disease. OBJECTIVE: This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of orally repeated administration of 5 µg, 10 µg, and 20 µg LSD in older healthy individuals. In the current paper, we present safety, tolerability, pharmacokinetics, and pharmacodynamic measures that relate to safety, tolerability, and dose response. METHODS: This was a phase 1 double-blind, placebo-controlled, randomized study. Volunteers were randomly assigned to 1 of 4 dose groups (5 µg, 10 µg, 20 µg LSD, and placebo), and received their assigned dose on six occasions (i.e., every 4 days). RESULTS: Forty-eight older healthy volunteers (mean age = 62.9 years) received placebo (n = 12), 5 µg (n = 12), 10 µg (n = 12), or 20 µg (n = 12) LSD. LSD plasma levels were undetectable for the 5 µg group and peak blood plasma levels for the 10 µg and 20 µg groups occurred at 30 min. LSD was well tolerated, and the frequency of adverse events was no higher than for placebo. Assessments of cognition, balance, and proprioception revealed no impairment. CONCLUSIONS: Our results suggest safety and tolerability of orally administered 5 µg, 10 µg, and 20 µg LSD every fourth day over a 21-day period and support further clinical development of LSD for the treatment and prevention of Alzheimer's disease (AD).


Assuntos
Cognição/efeitos dos fármacos , Alucinógenos/administração & dosagem , Alucinógenos/farmacologia , Dietilamida do Ácido Lisérgico/administração & dosagem , Dietilamida do Ácido Lisérgico/farmacocinética , Propriocepção/efeitos dos fármacos , Administração Oral , Idoso , Cognição/fisiologia , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Propriocepção/fisiologia , Tempo de Reação/efeitos dos fármacos , Tempo de Reação/fisiologia
5.
Proc Natl Acad Sci U S A ; 113(17): 4853-8, 2016 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-27071089

RESUMO

Lysergic acid diethylamide (LSD) is the prototypical psychedelic drug, but its effects on the human brain have never been studied before with modern neuroimaging. Here, three complementary neuroimaging techniques: arterial spin labeling (ASL), blood oxygen level-dependent (BOLD) measures, and magnetoencephalography (MEG), implemented during resting state conditions, revealed marked changes in brain activity after LSD that correlated strongly with its characteristic psychological effects. Increased visual cortex cerebral blood flow (CBF), decreased visual cortex alpha power, and a greatly expanded primary visual cortex (V1) functional connectivity profile correlated strongly with ratings of visual hallucinations, implying that intrinsic brain activity exerts greater influence on visual processing in the psychedelic state, thereby defining its hallucinatory quality. LSD's marked effects on the visual cortex did not significantly correlate with the drug's other characteristic effects on consciousness, however. Rather, decreased connectivity between the parahippocampus and retrosplenial cortex (RSC) correlated strongly with ratings of "ego-dissolution" and "altered meaning," implying the importance of this particular circuit for the maintenance of "self" or "ego" and its processing of "meaning." Strong relationships were also found between the different imaging metrics, enabling firmer inferences to be made about their functional significance. This uniquely comprehensive examination of the LSD state represents an important advance in scientific research with psychedelic drugs at a time of growing interest in their scientific and therapeutic value. The present results contribute important new insights into the characteristic hallucinatory and consciousness-altering properties of psychedelics that inform on how they can model certain pathological states and potentially treat others.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/efeitos dos fármacos , Estado de Consciência/efeitos dos fármacos , Alucinações/fisiopatologia , Alucinógenos/farmacologia , Dietilamida do Ácido Lisérgico/farmacologia , Imageamento por Ressonância Magnética/métodos , Magnetoencefalografia/métodos , Imagem Multimodal/métodos , Encéfalo/fisiopatologia , Circulação Cerebrovascular/efeitos dos fármacos , Conectoma , Estado de Consciência/fisiologia , Alucinações/induzido quimicamente , Humanos , Rede Nervosa/efeitos dos fármacos , Oxigênio/sangue , Receptor 5-HT2A de Serotonina/fisiologia , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia , Marcadores de Spin , Transmissão Sináptica/efeitos dos fármacos
6.
Biol Psychiatry ; 78(8): 554-62, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24495461

RESUMO

BACKGROUND: The compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals. METHODS: In a double-blind, placebo-controlled, balanced-order study, MDMA was orally administered to 25 physically and mentally healthy individuals. Arterial spin labeling and seed-based resting state functional connectivity (RSFC) were used to produce spatial maps displaying changes in cerebral blood flow (CBF) and RSFC after MDMA administration. Participants underwent two arterial spin labeling and two blood oxygen level-dependent scans in a 90-minute scan session; MDMA and placebo study days were separated by 1 week. RESULTS: Marked increases in positive mood were produced by MDMA. Decreased CBF only was observed after MDMA, and this was localized to the right medial temporal lobe (MTL), thalamus, inferior visual cortex, and the somatosensory cortex. Decreased CBF in the right amygdala and hippocampus correlated with ratings of the intensity of global subjective effects of MDMA. The RSFC results complemented the CBF results, with decreases in RSFC between midline cortical regions, the medial prefrontal cortex, and MTL regions, and increases between the amygdala and hippocampus. There were trend-level correlations between these effects and ratings of intense and positive subjective effects. CONCLUSIONS: The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug's characteristic subjective effects arise from its modulation of spontaneous brain activity.


Assuntos
Afeto/fisiologia , Tonsila do Cerebelo/efeitos dos fármacos , N-Metil-3,4-Metilenodioxianfetamina/administração & dosagem , Oxigênio/sangue , Serotoninérgicos/administração & dosagem , Adulto , Circulação Cerebrovascular/efeitos dos fármacos , Método Duplo-Cego , Feminino , Voluntários Saudáveis , Hipocampo/efeitos dos fármacos , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Córtex Pré-Frontal/efeitos dos fármacos , Lobo Temporal/efeitos dos fármacos , Adulto Jovem
7.
J Neurosci ; 33(38): 15171-83, 2013 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-24048847

RESUMO

Psychedelic drugs produce profound changes in consciousness, but the underlying neurobiological mechanisms for this remain unclear. Spontaneous and induced oscillatory activity was recorded in healthy human participants with magnetoencephalography after intravenous infusion of psilocybin--prodrug of the nonselective serotonin 2A receptor agonist and classic psychedelic psilocin. Psilocybin reduced spontaneous cortical oscillatory power from 1 to 50 Hz in posterior association cortices, and from 8 to 100 Hz in frontal association cortices. Large decreases in oscillatory power were seen in areas of the default-mode network. Independent component analysis was used to identify a number of resting-state networks, and activity in these was similarly decreased after psilocybin. Psilocybin had no effect on low-level visually induced and motor-induced gamma-band oscillations, suggesting that some basic elements of oscillatory brain activity are relatively preserved during the psychedelic experience. Dynamic causal modeling revealed that posterior cingulate cortex desynchronization can be explained by increased excitability of deep-layer pyramidal neurons, which are known to be rich in 5-HT2A receptors. These findings suggest that the subjective effects of psychedelics result from a desynchronization of ongoing oscillatory rhythms in the cortex, likely triggered by 5-HT2A receptor-mediated excitation of deep pyramidal cells.


Assuntos
Córtex Cerebral/efeitos dos fármacos , Sincronização Cortical/efeitos dos fármacos , Alucinógenos/farmacologia , Psilocibina/farmacologia , Adulto , Análise de Variância , Eletrocardiografia , Humanos , Magnetoencefalografia , Masculino , Modelos Neurológicos , Vias Neurais/efeitos dos fármacos , Dinâmica não Linear , Estimulação Luminosa , Descanso
8.
Alcohol Clin Exp Res ; 37(5): 885-9, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23278769

RESUMO

BACKGROUND: Thiamine deficiency in patients who abuse alcohol can cause Wernicke's encephalopathy (WE). Thiamine supplements are given to prevent this complication. Guidelines exist for giving thiamine supplementation in the inpatient population. However, similar guidelines are not available for clinicians detoxifying patients in the community, and consequently, assessment of risk of WE and prophylaxis can be inconsistent. METHODS: A scoring system to assess risk of WE was developed and evaluated by comparing practice before and after introduction of the system. One hundred and twenty-six cases requiring alcohol detoxification were examined: 94 before introduction of the scoring system and 32 afterward. RESULTS: Before introduction of the scoring system, a risk assessment for developing WE was performed in 30% of patients and parenteral thiamine prescribed in 32%. After introduction of the scoring system, risk assessment and administration of parenteral thiamine increased to 100 and 75%, respectively. There was 1 probable case of WE before introduction of the scoring system and none afterward. CONCLUSIONS: We conclude that assessment of WE is often inadequate, leading to inadequate thiamine administration. The new scoring system allows simple, structured risk assessment for WE and thus guides appropriate thiamine administration. This is of most value to clinicians treating the consequences of alcohol dependence in the community.


Assuntos
Medição de Risco/métodos , Deficiência de Tiamina/prevenção & controle , Tiamina/uso terapêutico , Complexo Vitamínico B/uso terapêutico , Encefalopatia de Wernicke/prevenção & controle , Transtornos Cognitivos , Dieta , Humanos , Náusea , Estudos Retrospectivos , Vômito , Redução de Peso
9.
Schizophr Bull ; 39(6): 1343-51, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23044373

RESUMO

Psilocybin is a classic psychedelic and a candidate drug model of psychosis. This study measured the effects of psilocybin on resting-state network and thalamocortical functional connectivity (FC) using functional magnetic resonance imaging (fMRI). Fifteen healthy volunteers received intravenous infusions of psilocybin and placebo in 2 task-free resting-state scans. Primary analyses focused on changes in FC between the default-mode- (DMN) and task-positive network (TPN). Spontaneous activity in the DMN is orthogonal to spontaneous activity in the TPN, and it is well known that these networks support very different functions (ie, the DMN supports introspection, whereas the TPN supports externally focused attention). Here, independent components and seed-based FC analyses revealed increased DMN-TPN FC and so decreased DMN-TPN orthogonality after psilocybin. Increased DMN-TPN FC has been found in psychosis and meditatory states, which share some phenomenological similarities with the psychedelic state. Increased DMN-TPN FC has also been observed in sedation, as has decreased thalamocortical FC, but here we found preserved thalamocortical FC after psilocybin. Thus, we propose that thalamocortical FC may be related to arousal, whereas DMN-TPN FC is related to the separateness of internally and externally focused states. We suggest that this orthogonality is compromised in early psychosis, explaining similarities between its phenomenology and that of the psychedelic state and supporting the utility of psilocybin as a model of early psychosis.


Assuntos
Cérebro/fisiopatologia , Conectoma/métodos , Alucinógenos/farmacologia , Rede Nervosa/efeitos dos fármacos , Psilocibina/farmacologia , Transtornos Psicóticos/fisiopatologia , Adulto , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/fisiopatologia , Cérebro/efeitos dos fármacos , Conectoma/instrumentação , Feminino , Alucinógenos/administração & dosagem , Alucinógenos/efeitos adversos , Humanos , Masculino , Rede Nervosa/fisiopatologia , Psilocibina/administração & dosagem , Psilocibina/efeitos adversos , Psicoses Induzidas por Substâncias/fisiopatologia , Reprodutibilidade dos Testes , Tálamo/efeitos dos fármacos , Tálamo/fisiopatologia , Adulto Jovem
10.
Alcohol Alcohol ; 47(3): 267-72, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22336766

RESUMO

AIMS: Ethyl glucuronide (EtG) in hair is a proposed biomarker for alcohol consumption. This study compares hair EtG concentrations with self-reported alcohol consumption data, in individuals with a range of alcohol use. METHODS: Hair was collected from 100 participants with a range of alcohol use. Participants completed an Alcohol Use Disorders Identification Test C questionnaire to record alcohol consumption. Participants were categorized into one of the four groups: tee-totallers (consuming 0 units a week), lower-risk drinkers (1-21 units a week), increasing-risk drinkers' consuming (22-50 units a week) and high-risk drinkers (over 50 units a week). Hair from the proximal 3 cm was analysed for EtG using gas chromatography-mass spectrometry/mass spectrometry. RESULTS: EtG was detected in 29 out of 100 hair samples. Based on the Society of Hair Testing (SOHT) threshold of 30 pg/mg EtG, the hair test identified alcohol consumption in 57.9% of high-risk drinkers, 45.5% of increasing-risk drinkers and only 9.8% of lower-risk drinkers. EtG sensitivity was highest for high-risk drinkers (consuming more than 50 units a week), identified to be 0.52 using a 30 pg/mg threshold and 0.58 using a 45 pg/mg threshold. A positive result is highly likely to indicate any drinking (positive predictive value, 1.00). A negative result does not provide good evidence for abstinence (negative predictive value, 0.23). CONCLUSIONS: EtG has been identified to be a low sensitivity marker that cannot be used quantitatively to determine alcohol exposure. EtG can be used qualitatively to indicate alcohol consumption with a positive result providing strong evidence for an individual drinking within the past 3 months.


Assuntos
Consumo de Bebidas Alcoólicas , Glucuronatos/análise , Cabelo/química , Autorrelato , Detecção do Abuso de Substâncias/métodos , Biomarcadores , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Valor Preditivo dos Testes , Sensibilidade e Especificidade
11.
J Psychopharmacol ; 25(11): 1562-7, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20395317

RESUMO

This study sought to assess the tolerability of intravenously administered psilocybin in healthy, hallucinogen-experienced volunteers in a mock-magnetic resonance imaging environment as a preliminary stage to a controlled investigation using functional magnetic resonance imaging to explore the effects of psilocybin on cerebral blood flow and activity. The present pilot study demonstrated that up to 2 mg of psilocybin delivered as a slow intravenous injection produces short-lived but typical drug effects that are psychologically and physiologically well tolerated. With appropriate care, this study supports the viability of functional magnetic resonance imaging work with psilocybin.


Assuntos
Alucinógenos/administração & dosagem , Psilocibina/administração & dosagem , Adulto , Circulação Cerebrovascular/efeitos dos fármacos , Tolerância a Medicamentos , Feminino , Seguimentos , Humanos , Injeções Intravenosas/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Projetos Piloto
12.
Eur Neuropsychopharmacol ; 19(10): 740-8, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19595579

RESUMO

The importance of the opioid receptor system in substance dependence is increasingly recognised. We used PET with the non-selective tracer [11C]diprenorphine to examine opioid receptor binding in early abstinence from alcohol dependence and the relationship to craving. We recruited 11 alcohol dependent patients and 13 controls. Subjects underwent one [11C]diprenorphine PET scan in early abstinence from dependent alcohol use (approximately 2 weeks) and 2 months later if continuously abstinent. Global and regional [11C]diprenorphine volumes of distribution (VD) were increased in alcohol dependent patients compared with controls but did not reach significance. We demonstrated a correlation between global and regional [11C]diprenorphine VD and craving in alcohol dependent patients which persisted in the anterior cingulate cortex into extended abstinence. This confirms previous work showing increased opioid receptor availability in early abstinence from substances of abuse and correlation with craving suggesting that the opioid system plays a fundamental role in this phase of addiction.


Assuntos
Alcoolismo/metabolismo , Comportamento Aditivo/metabolismo , Encéfalo/metabolismo , Diprenorfina/análise , Tomografia por Emissão de Pósitrons/métodos , Receptores Opioides/metabolismo , Adulto , Alcoolismo/diagnóstico por imagem , Alcoolismo/psicologia , Comportamento Aditivo/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Isótopos de Carbono/análise , Estudos de Casos e Controles , Humanos , Masculino , Pessoa de Meia-Idade , Antagonistas de Entorpecentes/análise , Ensaio Radioligante/métodos , Síndrome de Abstinência a Substâncias/metabolismo
13.
Br J Psychiatry ; 193(1): 65-72, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18700222

RESUMO

BACKGROUND: Drugs of dependence cause dopamine release in the rat striatum. Human neuroimaging studies have shown an increase in dopamine in the equivalent region in response to stimulants and other drugs. AIMS: We tested whether opioids provoke dopamine release and its relationship to the subjective experience. METHOD: In two combined studies 14 heroin addicts on methadone maintenance treatment underwent two positron emission tomography brain scans of the dopamine system using [(11)C]-raclopride following an injection of placebo and either 50 mg intravenous diamorphine or 10 mg subcutaneous hydromorphone in a double-blind, random order design. RESULTS: Both opioids produced marked subjective and physiological effects, but no measurable change in [(11)C]-raclopride binding. CONCLUSIONS: The absence of a dopamine response to opioid agonists contrasts with that found with stimulant drugs and suggests dopamine may not play the same role in addiction to opioids. This questions the role of dopamine in the subjective experience of heroin in opioid addicts.


Assuntos
Analgésicos Opioides/uso terapêutico , Encéfalo/metabolismo , Dopamina/metabolismo , Dependência de Heroína/reabilitação , Metadona/uso terapêutico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Método Duplo-Cego , Dependência de Heroína/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons
14.
J Psychopharmacol ; 22(1): 7-10, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18187528

RESUMO

The aim of this study was to make a comparison of brain structure between a group of opioid-dependent subjects and healthy controls. We report the results of an ;optimized' voxel-based morphometry study on a sample of nine opioid-dependent subjects with no comorbid substance misuse disorders versus 21 healthy controls. We found a significant reduction in grey matter volume of the thalamus after controlling for age and total grey matter volume. Regression analysis of substance use variables in the opioid-dependent sample shows that only level of alcohol use negatively predicts grey matter volume for this region of difference. We suggest that level of nondependent alcohol use could influence reduced thalamic grey matter volume in opioid-dependent subjects.


Assuntos
Etanol/efeitos adversos , Transtornos Relacionados ao Uso de Opioides/patologia , Tálamo/efeitos dos fármacos , Consumo de Bebidas Alcoólicas , Humanos , Análise de Regressão , Tálamo/patologia
15.
Psychopharmacology (Berl) ; 196(4): 611-21, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18038222

RESUMO

RATIONALE: Acute tyrosine/phenylalanine depletion (ATPD) is a validated neurobiological challenge that results in reduced dopaminergic neurotransmission, allowing examination of the effects of a hypodopaminergic state on craving-related processes. OBJECTIVES: We studied 16 nonabstaining smokers (>10 cigarettes/day; 9 males; age 20-33 years) to whom was administered a tyrosine/phenylalanine-free mixture (TYR/PHE-free) and a balanced amino acid mixture (BAL) in a double-blind, counterbalanced, crossover design. METHODS: Subjective cigarette craving, attentional bias to smoking-related word cues, relative value of cigarettes, negative mood, and expired carbon monoxide (CO) levels were measured at various timepoints through 300 min. Participants smoked at hourly intervals to prevent acute nicotine withdrawal during testing. RESULTS: The TYR/PHE-free mixture, as compared to the BAL mixture, was associated with a greater increase in CO levels from baseline (p = 0.01). Adjusting for the potential confounding influence of between-condition differences in CO levels across time, TYR/PHE-free mixture was associated with increased demand for cigarettes (p = 0.01) and decreased attentional bias toward smoking-related words (p = 0.003). There were no significant differences between conditions in either subjective craving or depressed or anxious mood (p values > 0.05). CONCLUSION: Among nonabstaining daily smokers, acute dopaminergic depletion via ATPD may influence smoking behavior and indices of smoking-related motivation, such as attentional bias to smoking cues and relative cigarette value, which are not readily captured by subjective craving.


Assuntos
Aminoácidos/metabolismo , Sinais (Psicologia) , Fenilalanina/deficiência , Fumar/psicologia , Tirosina/deficiência , Adulto , Estudos Cross-Over , Dopamina/fisiologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Análise Multivariada , Tempo de Reação , Abandono do Hábito de Fumar/psicologia
16.
Br J Psychiatry ; 191: 63-9, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17602127

RESUMO

BACKGROUND: Although opioid receptor function in humans is clearly reduced during opioid dependence, what happens to the receptor in early abstinence is not understood. AIMS: This study sought to examine changes in opioid receptor availability in early abstinence from opioid dependence. METHOD: Ten people with opioid dependence who had completed in-patient detoxification and 20 healthy controls underwent [11C]-diprenorphine positron emission tomography. Clinical variables were assessed with structured questionnaires. Opioid receptor binding was characterised as the volume of distribution of [11C]-diprenorphine using a template of predefined brain volumes and an exploratory voxel-by-voxel analysis. RESULTS: Compared with controls, participants with opioid dependence had increased [11C]-diprenorphine binding in the whole brain and in 15 of the 21 a priori regions studied. CONCLUSIONS: This study suggests that opioid receptor binding is increased throughout the brain in early abstinence from dependent opioid use. These data complement the findings in cocaine and alcohol dependence.


Assuntos
Encéfalo/metabolismo , Diprenorfina , Antagonistas de Entorpecentes , Alcaloides Opiáceos/metabolismo , Transtornos Relacionados ao Uso de Opioides/metabolismo , Receptores Opioides/metabolismo , Adulto , Encéfalo/diagnóstico por imagem , Estudos de Casos e Controles , Diprenorfina/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Antagonistas de Entorpecentes/metabolismo , Alcaloides Opiáceos/farmacologia , Tomografia por Emissão de Pósitrons/métodos , Síndrome de Abstinência a Substâncias/metabolismo
17.
J Pharmacol Exp Ther ; 312(1): 309-15, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15347732

RESUMO

Substitute methadone prescribing is one of the main modes of treatment for opioid dependence with established evidence for improved health and social outcomes. However, the pharmacology underpinning the effects of methadone is little studied despite controversies about dosing in relation to outcome. We therefore examined the relationship between methadone dose and occupation of opioid receptors in brain using the positron emission tomography (PET) radioligand [(11)C]diprenorphine in humans and rats. Eight opioid-dependent subjects stable on their substitute methadone (18-90 mg daily) had an [(11)C]diprenorphine PET scan at predicted peak plasma levels of methadone. These were compared with eight healthy controls. No difference in [(11)C]diprenorphine binding was found between the groups, with no relationship between methadone dose and occupancy. Adult male Sprague-Dawley rats that had been given an acute i.v. injection of methadone hydrochloride (0.35, 0.5, 0.7, or 1.0 mg kg(-1)) before [(11)C]diprenorphine showed a dose-dependent increase in biodistribution but no reduction in [(11)C]diprenorphine binding. We suggest that the lack of a dose-dependent relationship between methadone dose, either given chronically in human or acutely in rat, and occupancy of opioid receptor measured with [(11)C]diprenorphine PET is related to efficacy of this opioid agonist at very low levels of opioid receptor occupancy. This has implications for understanding the actions of methadone in comparison with other opioid drugs such as partial agonists and antagonists.


Assuntos
Diprenorfina/farmacologia , Metadona/farmacologia , Transtornos Relacionados ao Uso de Opioides/metabolismo , Receptores Opioides/metabolismo , Adulto , Animais , Comportamento Aditivo , Radioisótopos de Carbono , Diprenorfina/química , Humanos , Masculino , Pessoa de Meia-Idade , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
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