84 results found
Erritzoe D, Rabiner E, Howes O, Serotonin release measured in the human brain: A PET study with [11C]CIMBI-36 and d-amphetamine challenge, Neuropsychopharmacology, ISSN: 0893-133X
Positron emission tomography (PET) enables non-invasive estimation of neurotransmitter fluctuations in the living human brain. While these methods have been applied to dopamine and some other transmitters, estimation of 5-hydroxytryptamine (5-HT; Serotonin) release has proved to be challenging. Here we demonstrate the utility of the novel 5-HT2A receptor agonist radioligand, [11C]CIMBI-36, and a d-amphetamine challenge to evaluate synaptic 5-HT changes in the living human brain. Seventeen healthy male volunteers received [11C]CIMBI-36 PET scans before and 3 hours after an oral dose of d-amphetamine (0.5 mg/kg). Dynamic PET data were acquired over 90 minutes, and the total volume of distribution (VT) in the frontal cortex and the cerebellum derived from a kinetic analysis using MA1. The frontal cortex binding potential (BPNDfrontal) was calculated as (VTfrontal/VTcerebellum)-1. BPNDfrontal = 1- (BPNDfrontalpost-dose/ BPNDfrontalbaseline) was used as an index of 5-HT release. Statistical inference was tested by means of a paired Students t-test evaluating a reduction in post-amphetamine [11C]CIMBI-36 BPNDfrontal .Following d-amphetamine administration, [11C]CIMBI-36 BPNDfrontal was reduced by 14 ± 13 % (p = 0.002). Similar effects were observed in other cortical regions examined in an exploratory analysis.[11C]CIMBI-36 binding is sensitive to synaptic serotonin release in the human brain, and when combined with a d-amphetamine challenge, the evaluation of the human brain serotonin system in neuropsychiatric disorders, such as major depression and Parkinson’s disease is enabled.
Timmermann Slater CB, Roseman L, Schartner M, et al., Neural correlates of the DMT experience as assessed with multivariate EEG, Scientific Reports, ISSN: 2045-2322
Studying transitions in and out of the altered state of consciousness caused by intravenous (IV) N,N-Dimethyltryptamine (DMT - a fast-acting tryptamine psychedelic) offers a safe and powerful means of advancing knowledge on the neurobiology of conscious states. Here we sought to investigate the effects of IV DMT on the power spectrum and signal diversity of human brain activity (6 female, 7 male) recorded via multivariate EEG, and plot relationships between subjective experience, brain activity and drug plasma concentrations across time. Compared with placebo, DMT markedly reduced oscillatory power in the alpha and beta bands and robustly increased spontaneous signal diversity. Time-referenced neurophenomenological analyses revealed close relationships between changes in various aspects of subjective experience and changes in brain activity. Importantly, the emergence of oscillatory activity within the delta and theta frequency bands was found to correlate with the peak of the experience - particularly its eyes-closed visual component. These findings highlight marked changes in oscillatory activity and signal diversity with DMT that parallel broad and specific components of the subjective experience, thus advancing our understanding of the neurobiological underpinnings of immersive states of consciousness.
Nestor LJ, Paterson LM, Murphy A, et al., 2019, Naltrexone differentially modulates the neural correlates of motor impulse control in abstinent alcohol-dependent and poly-substance dependent individuals, European Journal of Neuroscience, Vol: 50, Pages: 2311-2321, ISSN: 0953-816X
Identifying key neural substrates in addiction disorders for targeted drug development remains a major challenge for clinical neuroscience. One emerging target is the opioid system, where substance‐dependent populations demonstrate prefrontal opioid dysregulation that predicts impulsivity and relapse. This may suggest that disturbances to the prefrontal opioid system could confer a risk for relapse in addiction due to weakened “top‐down” control over impulsive behaviour. Naltrexone is currently licensed for alcohol dependence and is also used clinically for impulse control disorders. Using a go/no‐go (GNG) task we examined the effects of acute naltrexone on the neural correlates of successful motor impulse control in abstinent alcoholics (AUD), abstinent poly substance‐dependent (poly‐SUD) individuals, and controls during a randomized double blind placebo controlled fMRI study. In the absence of any differences on GNG task performance, the AUD group showed a significantly greater BOLD response compared to the control group in lateral and medial prefrontal regions during both placebo and naltrexone treatments; effects that were positively correlated with alcohol abstinence. There was also a dissociation in the positive modulating effects of naltrexone in the orbitofrontal cortex (OFC) and anterior insula cortex (AIC) of the AUD and poly‐SUD groups respectively. Self‐reported trait impulsivity in the poly‐SUD group also predicted the effect of naltrexone in the AIC. These results suggest that acute naltrexone differentially amplifies neural responses within two distinct regions of a salience network during successful motor impulse control in abstinent AUD and poly‐SUD groups, which are predicted by trait impulsivity in the poly‐SUD group.
Kuypers KPC, Ng L, Erritzoe D, et al., Microdosing psychedelics: More questions than answers? An overview and suggestions for future research, JOURNAL OF PSYCHOPHARMACOLOGY, ISSN: 0269-8811
Erritzoe D, Godlewska BR, Rizzo G, et al., 2019, Reduced serotonin release in patients with major depression: a PET study with [11C]Cimbi-36 and d-amphetamine challenge, 29th International Symposium on Cerebral Blood Flow, Metabolism and Function / 14th International Conference on Quantification of Brain Function with PET (BRAIN and BRAIN Pet), Publisher: SAGE PUBLICATIONS INC, Pages: 548-549, ISSN: 0271-678X
Madsen MK, Fisher PM, Burmester D, et al., 2019, Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels, NEUROPSYCHOPHARMACOLOGY, Vol: 44, Pages: 1328-1334, ISSN: 0893-133X
Madsen MK, Fisher PM, Burmester D, et al., 2019, Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels (vol 44, pg 1328, 2019), NEUROPSYCHOPHARMACOLOGY, Vol: 44, Pages: 1336-1337, ISSN: 0893-133X
Erritzoe D, Smith J, Fisher PM, et al., 2019, Recreational use of psychedelics is associated with elevated personality trait openness: Exploration of associations with brain serotonin markers., J Psychopharmacol, Pages: 269881119827891-269881119827891
BACKGROUND:: Recent studies have suggested therapeutic benefits of psychedelics for a variety of mental health conditions. The understanding of how single psychedelic administrations can induce long-lasting effects are, in large, still lacking. However, recent studies in both healthy and clinical populations suggest a role for personality changes. AIM:: To test support for some of these plausible mechanisms we evaluated (cross-sectional) associations between recreational use of psychedelics and 3,4-methylene-dioxymethamphetamine (MDMA) and (a) personality measures and (b) key markers of cerebral serotonergic signalling (serotonin transporter and serotonin-2A-receptor binding). METHODS:: In 10 psychedelic-preferring recreational users, 14 MDMA-preferring users and 21 non-using controls, personality was assessed using the 'big five' instrument Revised NEO Personality Inventory (NEO-PI-R). Frontal serotonin transporter and serotonin-2A-receptor binding potentials were quantified using [11C]DASB and [18F]altanserin positron emission tomography, respectively. RESULTS:: Of the five NEO-PI-R traits, only openness to experience scores differed between the three groups; psychedelic-preferring recreational users showing higher openness to experience scores when compared with both MDMA-preferring users and controls. Openness to experience scores were positively associated with lifetime number of psychedelic exposures, and among all MDMA-preferring user/psychedelic-preferring recreational user individuals, frontal serotonin transporter binding - but not frontal serotonin-2A-receptor binding - was positively associated with openness to experience. CONCLUSION:: Our findings from this cross-sectional study support increasing evidence of a positive association between psychedelic experiences and openness to experience, and (a) expands this to the context of 'recreational' psychedelics use, and (b) links serotonergic neurotransmission to openness to experience. A modulation of perso
Madsen MK, Burmester D, Stenbaek DS, et al., 2019, Psilocybin occupancy of brain serotonin 2A receptors correlates with psilocin levels and subjective experience: a [11C]Cimbi-36 PET study in humans, 31st Congress of the European-College-of-Neuropsychopharmacology (ECNP), Publisher: ELSEVIER SCIENCE BV, Pages: S304-S305, ISSN: 0924-977X
Erritzoe D, Roseman L, Nour MM, et al., 2018, Effects of psilocybin therapy on personality structure, Acta Psychiatrica Scandinavica, Vol: 138, Pages: 368-378, ISSN: 1600-0447
ObjectiveTo explore whether psilocybin with psychological support modulates personality parameters in patients suffering from treatment‐resistant depression (TRD).MethodTwenty patients with moderate or severe, unipolar, TRD received oral psilocybin (10 and 25 mg, one week apart) in a supportive setting. Personality was assessed at baseline and at 3‐month follow‐up using the Revised NEO Personality Inventory (NEO‐PI‐R), the subjective psilocybin experience with Altered State of Consciousness (ASC) scale, and depressive symptoms with QIDS‐SR16.ResultsNeuroticism scores significantly decreased while Extraversion increased following psilocybin therapy. These changes were in the direction of the normative NEO‐PI‐R data and were both predicted, in an exploratory analysis, by the degree of insightfulness experienced during the psilocybin session. Openness scores also significantly increased following psilocybin, whereas Conscientiousness showed trend‐level increases, and Agreeableness did not change.ConclusionOur observation of changes in personality measures after psilocybin therapy was mostly consistent with reports of personality change in relation to conventional antidepressant treatment, although the pronounced increases in Extraversion and Openness might constitute an effect more specific to psychedelic therapy. This needs further exploration in future controlled studies, as do the brain mechanisms of postpsychedelic personality change.
Near-death experiences (NDEs) are complex subjective experiences, which have been previously associated with the psychedelic experience and more specifically with the experience induced by the potent serotonergic, N,N-Dimethyltryptamine (DMT). Potential similarities between both subjective states have been noted previously, including the subjective feeling of transcending one’s body and entering an alternative realm, perceiving and communicating with sentient ‘entities’ and themes related to death and dying. In this within-subjects placebo-controled study we aimed to test the similarities between the DMT state and NDEs, by administering DMT and placebo to 13 healthy participants, who then completed a validated and widely used measure of NDEs. Results revealed significant increases in phenomenological features associated with the NDE, following DMT administration compared to placebo. Also, we found significant relationships between the NDE scores and DMT-induced ego-dissolution and mystical-type experiences, as well as a significant association between NDE scores and baseline trait ‘absorption’ and delusional ideation measured at baseline. Furthermore, we found a significant overlap in nearly all of the NDE phenomenological features when comparing DMT-induced NDEs with a matched group of ‘actual’ NDE experiencers. These results reveal a striking similarity between these states that warrants further investigation.
Carhart-Harris RL, Roseman L, Haijen E, et al., 2018, Psychedelics and the essential importance of context, JOURNAL OF PSYCHOPHARMACOLOGY, Vol: 32, Pages: 725-731, ISSN: 0269-8811
Szigeti B, Winstock AR, Erritzoe D, et al., 2018, Are ecstasy induced serotonergic alterations overestimated for the majority of users?, JOURNAL OF PSYCHOPHARMACOLOGY, Vol: 32, Pages: 741-748, ISSN: 0269-8811
Carhart-Harris RL, Bolstridge M, Day CMJ, et al., 2017, Psilocybin with psychological support for treatment-resistant depression: six-month follow-up, Psychopharmacology, Vol: 235, Pages: 399-408, ISSN: 0033-3158
RATIONALE: Recent clinical trials are reporting marked improvements in mental health outcomes with psychedelic drug-assisted psychotherapy. OBJECTIVES: Here, we report on safety and efficacy outcomes for up to 6 months in an open-label trial of psilocybin for treatment-resistant depression. METHODS: Twenty patients (six females) with (mostly) severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 and 25 mg, 7 days apart) in a supportive setting. Depressive symptoms were assessed from 1 week to 6 months post-treatment, with the self-rated QIDS-SR16 as the primary outcome measure. RESULTS: Treatment was generally well tolerated. Relative to baseline, marked reductions in depressive symptoms were observed for the first 5 weeks post-treatment (Cohen's d = 2.2 at week 1 and 2.3 at week 5, both p < 0.001); nine and four patients met the criteria for response and remission at week 5. Results remained positive at 3 and 6 months (Cohen's d = 1.5 and 1.4, respectively, both p < 0.001). No patients sought conventional antidepressant treatment within 5 weeks of psilocybin. Reductions in depressive symptoms at 5 weeks were predicted by the quality of the acute psychedelic experience. CONCLUSIONS: Although limited conclusions can be drawn about treatment efficacy from open-label trials, tolerability was good, effect sizes large and symptom improvements appeared rapidly after just two psilocybin treatment sessions and remained significant 6 months post-treatment in a treatment-resistant cohort. Psilocybin represents a promising paradigm for unresponsive depression that warrants further research in double-blind randomised control trials.
Erritzoe D, Richards WA, 2017, Lessons to be learned from early psychedelic therapy in Denmark, NORDIC JOURNAL OF PSYCHIATRY, Vol: 71, Pages: 487-488, ISSN: 0803-9488
Erritzoe D, Nutt DJ, Carhart-Harris R, 2017, Concerns regarding conclusions made about LSD-treatments, HISTORY OF PSYCHIATRY, Vol: 28, Pages: 257-258, ISSN: 0957-154X
Erritzoe D, Colasanti A, Searle G, et al., 2017, Serotonin release measured in the human brain: A PET study with [C-11]Cimbi-36 and d-amphetamine challenge, 28th International Symposium on Cerebral Blood Flow, Metabolism and Function / 13th International Conference on Quantification of Brain Function with PET, Publisher: SAGE PUBLICATIONS INC, Pages: 73-73, ISSN: 0271-678X
Recent work with noninvasive human brain imaging has started to investigate the effects of 3,4-methylenedioxymethamphetamine (MDMA) on large-scale patterns of brain activity. MDMA, a potent monoamine-releaser with particularly pronounced serotonin- releasing properties, has unique subjective effects that include: marked positive mood, pleasant/unusual bodily sensations and pro-social, empathic feelings. However, the neurobiological basis for these effects is not properly understood, and the present analysis sought to address this knowledge gap. To do this, we administered MDMA-HCl (100 mg p.o.) and, separately, placebo (ascorbic acid) in a randomized, double-blind, repeated-measures design with twenty-five healthy volunteers undergoing fMRI scanning. We then employed a measure of global resting-state functional brain connectivity and follow-up seed-to-voxel analysis to the fMRI data we acquired. Results revealed decreased right insula/salience network functional connectivity under MDMA. Furthermore, these decreases in right insula/salience network connectivity correlated with baseline trait anxiety and acute experiences of altered bodily sensations under MDMA. The present findings highlight insular disintegration (ie, compromised salience network membership) as a neurobiological signature of the MDMA experience, and relate this brain effect to trait anxiety and acutely altered bodily sensations–both of which are known to be associated with insular functioning.
Kalk NJ, Guo Q, Owen D, et al., 2017, Decreased hippocampal translocator protein (18 kDa) expression in alcohol dependence: a [(11)C]PBR28 PET study, Translational Psychiatry, Vol: 7, ISSN: 2158-3188
Repeated withdrawal from alcohol is clinically associated with progressive cognitive impairment. Microglial activation occurring during pre-clinical models of alcohol withdrawal is associated with learning deficits. We investigated whether there was microglial activation in recently detoxified alcohol-dependent patients (ADP), using [(11)C]PBR28 positron emission tomography (PET), selective for the 18kDa translocator protein (TSPO) highly expressed in activated microglia and astrocytes. We investigated the relationship between microglial activation and cognitive performance. Twenty healthy control (HC) subjects (45±13; M:F 14:6) and nine ADP (45±6, M:F 9:0) were evaluated. Dynamic PET data were acquired for 90 min following an injection of 331±15 MBq [(11)C]PBR28. Regional volumes of distribution (VT) for regions of interest (ROIs) identified a priori were estimated using a two-tissue compartmental model with metabolite-corrected arterial plasma input function. ADP had an ~20% lower [(11)C]PBR28 VT, in the hippocampus (F(1,24) 5.694; P=0.025), but no difference in VT in other ROIs. Hippocampal [(11)C]PBR28 VT was positively correlated with verbal memory performance in a combined group of HC and ADP (r=0.720, P<0.001), an effect seen in HC alone (r=0.738; P=0.001) but not in ADP. We did not find evidence for increased microglial activation in ADP, as seen pre-clinically. Instead, our findings suggest lower glial density or an altered activation state with lower TSPO expression. The correlation between verbal memory and [(11)C]PBR28 VT, raises the possibility that abnormalities of glial function may contribute to cognitive impairment in ADP.
Limbrick-Oldfield E, Mick I, Cocks R, et al., 2017, Neural substrates of cue reactivity and craving in gambling disorder, Translational Psychiatry, Vol: 7, ISSN: 2158-3188
Cue reactivity is an established procedure in addictions research for examining the subjective experience and neural basis of craving. This experiment sought to quantify cue-related brain responses in Gambling Disorder using personally tailored cues in conjunction with subjective craving, as well as a comparison with appetitive non-gambling stimuli. Participants with Gambling Disorder (n=19) attending treatment and 19 controls viewed personally tailored blocks of gambling-related cues, as well as neutral cues and highly appetitive (food) images during a functional MRI scan performed ~2-3 hours after a usual meal. fMRI analysis examined cue-related brain activity, cue-related changes in connectivity, and associations with block-by-block craving ratings. Craving ratings in the participants with Gambling Disorder increased following gambling cues compared with non-gambling cues. fMRI analysis revealed group differences in left insula and anterior cingulate cortex, with the Gambling Disorder group showing greater reactivity to the gambling cues, but no differences to the food cues. In participants with Gambling Disorder, craving to gamble correlated positively with gambling cue-related activity in the bilateral insula and ventral striatum, and negatively with functional connectivity between the ventral striatum and the medial PFC. Gambling cues, but not food cues, elicit increased brain responses in reward-related circuitry in individuals with Gambling Disorder (compared to controls), providing support for the incentive sensitisation theory of addiction. Activity in the insula co-varied with craving intensity, and may be a target for interventions.
Laursen HR, Henningsson S, Macoveanu J, et al., 2016, Serotonergic neurotransmission in emotional processing: New evidence from long-term recreational poly-drug ecstasy use, JOURNAL OF PSYCHOPHARMACOLOGY, Vol: 30, Pages: 1296-1304, ISSN: 0269-8811
Mick I, Ramos C, Myers J, et al., 2016, Evidence for GABA-A receptor dysregulation in gambling disorder: correlation with impulsivity., Addiction Biology, Vol: 22, Pages: 1601-1609, ISSN: 1369-1600
Background: As a behavioral addiction, gambling disorder (GD) provides an opportunity to characterize addictive processes without the potentially confounding effects of chronic excessive drug and alcohol exposure. Impulsivity is an established precursor to such addictive behaviours and GD is associated with greater impulsivity. There is also evidence of GABAergic dysregulation in substance addiction and in impulsivity. Methods: This study therefore investigated GABAA receptor availability in 15 individuals with GD and 19 healthy volunteers (HV) using [11C]Ro15-4513, a relatively selective α5 benzodiazepine receptor PET tracer and its relationship with impulsivity. Results: We found significantly higher [11C]Ro15-4513 total distribution volume (VT) in the right hippocampus in the GD group compared with HV. We found higher levels of The ‘Negative Urgency’ construct of impulsivity in GD and these were positively associated with higher [11C]Ro15-4513 VT in the amygdala in the GD group; no such significant correlations were evident in the HV group. Conclusions: These results contrast with reduced binding of GABAergic PET ligands described previously in alcohol and opiate addiction and add to growing evidence for distinctions in the neuropharmacology between substance and behavioral addictions. These results provide the first characterization of GABAA receptors in GD with [11C]Ro15-4513 PET and show greater α5 receptor availability and positive correlations with trait impulsivity. This GABAergic dysregulation is potential target for treatment.
Carhart-Harris RL, Bolstridge M, Rucker J, et al., 2016, Psilocybin with psychological support for treatment-resistant depression: an open-label feasibility study, Lancet Psychiatry, Vol: 3, Pages: 619-627, ISSN: 2215-0374
BACKGROUND: Psilocybin is a serotonin receptor agonist that occurs naturally in some mushroom species. Recent studies have assessed the therapeutic potential of psilocybin for various conditions, including end-of-life anxiety, obsessive-compulsive disorder, and smoking and alcohol dependence, with promising preliminary results. Here, we aimed to investigate the feasibility, safety, and efficacy of psilocybin in patients with unipolar treatment-resistant depression. METHODS: In this open-label feasibility trial, 12 patients (six men, six women) with moderate-to-severe, unipolar, treatment-resistant major depression received two oral doses of psilocybin (10 mg and 25 mg, 7 days apart) in a supportive setting. There was no control group. Psychological support was provided before, during, and after each session. The primary outcome measure for feasibility was patient-reported intensity of psilocybin's effects. Patients were monitored for adverse reactions during the dosing sessions and subsequent clinic and remote follow-up. Depressive symptoms were assessed with standard assessments from 1 week to 3 months after treatment, with the 16-item Quick Inventory of Depressive Symptoms (QIDS) serving as the primary efficacy outcome. This trial is registered with ISRCTN, number ISRCTN14426797. FINDINGS: Psilocybin's acute psychedelic effects typically became detectable 30-60 min after dosing, peaked 2-3 h after dosing, and subsided to negligible levels at least 6 h after dosing. Mean self-rated intensity (on a 0-1 scale) was 0·51 (SD 0·36) for the low-dose session and 0·75 (SD 0·27) for the high-dose session. Psilocybin was well tolerated by all of the patients, and no serious or unexpected adverse events occurred. The adverse reactions we noted were transient anxiety during drug onset (all patients), transient confusion or thought disorder (nine patients), mild and transient nausea (four patients), and transient headache (four patients). Relative to
Mick I, Myers J, Ramos AC, et al., 2016, Blunted Endogenous Opioid Release Following an Oral Amphetamine Challenge in Pathological Gamblers, 3rd International Conference on Behavioral Addictions, Publisher: Akadémiai Kiadó, Pages: 30-30, ISSN: 2063-5303
Taylor EM, Murphy A, Boyapati V, et al., 2016, Impulsivity in abstinent alcohol and polydrug dependence: a multidimensional approach, Psychopharmacology, Vol: 233, Pages: 1487-1499, ISSN: 1432-2072
Knudsen GM, Jensen PS, Erritzoe D, et al., 2016, The Center for Integrated Molecular Brain Imaging (Cimbi) database, NEUROIMAGE, Vol: 124, Pages: 1213-1219, ISSN: 1053-8119
Carhart-Harris RL, Murphy K, Leech R, et al., 2015, The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level-Dependent Resting State Functional Connectivity, Biological Psychiatry, Vol: 78, Pages: 554-562, ISSN: 1873-2402
BackgroundThe compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals.MethodsIn 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.ResultsMarked 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.ConclusionsThe 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.
Lingford-Hughes AR, Mick I, Myers J, et al., 2015, Blunted endogenous opioid release following an oral amphetamine challenge in pathological gamblers, Neuropsychopharmacology, Vol: 41, Pages: 1742-1750, ISSN: 1740-634X
Pathological gambling is a psychiatric disorder and the first recognized behavioral addiction, with similarities to substance use disorders but without the confounding effects of drug-related brain changes. Pathophysiology within the opioid receptor system is increasingly recognized in substance dependence, with higher mu-opioid receptor (MOR) availability reported in alcohol, cocaine and opiate addiction. Impulsivity, a risk factor across the addictions, has also been found to be associated with higher MOR availability. The aim of this study was to characterize baseline MOR availability and endogenous opioid release in pathological gamblers (PG) using [¹¹C]carfentanil PET with an oral amphetamine challenge. 14 PG and 15 healthy volunteers (HV) underwent two [¹¹C]carfentanil PET scans, before and after an oral administration of 0.5 mg/kg of d-amphetamine. The change in [¹¹C]carfentanil binding between baseline and post-amphetamine scans (ΔBPND) was assessed in 10 regions of interest (ROI). MOR availability did not differ between PG and HV groups. As seen previously, oral amphetamine challenge led to significant reductions in [¹¹C]carfentanil BPND in 8/10 ROI in HV. PG demonstrated significant blunting of opioid release compared with HV. PG also showed blunted amphetamine-induced euphoria and alertness compared with HV. Exploratory analysis revealed that impulsivity positively correlated with caudate baseline BPND in PG only. This study provides the first evidence of blunted endogenous opioid release in PG. Our findings are consistent with growing evidence that dysregulation of endogenous opioids may play an important role in the pathophysiology of addictions.
Lingford-Hughes A, McGonigle J, Mick I, et al., 2015, An fMRI study of nalmefene on alcohol effects in reward anticipation in alcohol dependence, 28th Congress of the European-College-of-Neuropsychopharmacology (ECNP), Publisher: ELSEVIER SCIENCE BV, Pages: S602-S603, ISSN: 0924-977X
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