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Varma MM, Zeng S, Singh L, Holmes EA, Huang J, Chiu MH, Hu X. A systematic review and meta-analysis of experimental methods for modulating intrusive memories following lab-analogue trauma exposure in non-clinical populations. Nat Hum Behav 2024:10.1038/s41562-024-01956-y. [PMID: 39169230 DOI: 10.1038/s41562-024-01956-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 07/15/2024] [Indexed: 08/23/2024]
Abstract
Experiencing trauma leads to intrusive memories (IMs), a hallmark symptom of post-traumatic stress disorder (PTSD), which also occurs transdiagnostically. Understanding why IMs increase or decrease is pivotal in developing interventions to support mental health. In this preregistered meta-analysis (PROSPERO: CRD42021224835), we included 134 articles (131 techniques, 606 effect sizes and 12,074 non-clinical participants) to investigate how experimental techniques alter IM frequency, intrusion-related distress and symptoms arising from lab-analogue trauma exposure. Eligible articles were identified by searching eight databases until 12 December 2023. To test potential publication biases, we employed methods including Egger's test and three-parameter selection models. We employed three-level multilevel modelling and meta-regressions to examine whether and how experimental techniques would modulate IM frequency and associated outcomes. Results showed that techniques (behavioural, pharmacological, neuromodulation) significantly reduced intrusion frequency (g = 0.16, 95% confidence interval [0.09, 0.23]). Notably, techniques aimed to reduce IMs also ameliorated intrusion-related distress and symptoms, while techniques that increased IMs exacerbated these related outcomes, thus highlighting IM's centrality in PTSD-like symptoms. Techniques tapping into mental imagery processing (for example, trauma reminder followed by playing Tetris) reduced intrusions when administered immediately after, or at a delayed time after trauma. Although our meta-analysis is limited to symptoms induced by lab-analogue trauma exposure, some lab-based results have now generalized to real-world trauma and IMs, highlighting the promising utility of lab-analogue trauma paradigms for intervention development.
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Affiliation(s)
- Mohith M Varma
- Department of Management, Marketing, and Information Systems, Hong Kong Baptist University, Hong Kong SAR, China
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China
| | - Shengzi Zeng
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China
- The State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA, USA
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Laura Singh
- Department of Psychology, Uppsala University, Uppsala, Sweden
- Swedish Collegium for Advanced Study, Uppsala, Sweden
| | - Emily A Holmes
- Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
| | - Jingyun Huang
- School of Computer Science and Engineering, Sun Yat-sen University, Guangzhou, China
| | - Man Hey Chiu
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China
| | - Xiaoqing Hu
- Department of Psychology, The University of Hong Kong, Hong Kong SAR, China.
- The State Key Lab of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong SAR, China.
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, China.
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2
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Doss MK, de Wit H, Gallo DA. The acute effects of psychoactive drugs on emotional episodic memory encoding, consolidation, and retrieval: A comprehensive review. Neurosci Biobehav Rev 2023; 150:105188. [PMID: 37085021 PMCID: PMC10247427 DOI: 10.1016/j.neubiorev.2023.105188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/13/2023] [Accepted: 04/17/2023] [Indexed: 04/23/2023]
Abstract
Psychoactive drugs modulate learning and emotional processes in ways that could impact their recreational and medical use. Recent work has revealed how drugs impact different stages of processing emotional episodic memories, specifically encoding (forming memories), consolidation (stabilizing memories), and retrieval (accessing memories). Drugs administered before encoding may preferentially impair (e.g., GABAA sedatives including alcohol and benzodiazepines, Δ9-tetrahydrocannabinol or THC, ketamine), enhance (e.g., dextroamphetamine and dextromethamphetamine), or both impair and enhance (i.e., ± 3,4-methylenedioxymethylamphetamine or MDMA) emotionally negative and positive compared to neutral memories. GABAA sedatives administered immediately post-encoding (during consolidation) can preferentially enhance emotional memories, though this selectivity may decline or even reverse (i.e., preferential enhancement of neutral memories) as the delay between encoding and retrieval increases. Finally, retrieving memories under the effects of THC, dextroamphetamine, MDMA, and perhaps GABAA sedatives distorts memory, with potentially greater selectively for emotional (especially positive) memories. We review these effects, propose neural mechanisms, discuss methodological considerations for future work, and speculate how drug effects on emotional episodic memory may contribute to drug use and abuse.
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Affiliation(s)
- Manoj K Doss
- Department of Psychiatry and Behavioral Sciences, Center for Psychedelic & Consciousness Research, USA.
| | - Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, USA
| | - David A Gallo
- Department of Psychology, University of Chicago, USA
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3
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Brain function changes reveal rapid antidepressant effects of nitrous oxide for treatment-resistant depression:Evidence from task-state EEG. Psychiatry Res 2023; 322:115072. [PMID: 36791487 DOI: 10.1016/j.psychres.2023.115072] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 01/15/2023] [Accepted: 01/22/2023] [Indexed: 01/28/2023]
Abstract
Nitrous oxide has rapid antidepressant effects in patients with treatment-resistant depression (TRD), but its underlying mechanisms of therapeutic actions are not well understood. Moreover, most of the current studies lack objective biological indicators to evaluate the changes of nitrous oxide-induced brain function for TRD. Therefore, this study assessed the effect of nitrous oxide on brain function for TRD based on event-related potential (ERP) components and functional connectivity networks (FCNs) methods. In this randomized, longitudinal, placebo-controlled trial, all TRD participants were divided into two groups to receive either a 1-hour inhalation of nitrous oxide or a placebo treatment, and they took part in the same task-state electroencephalogram (EEG) experiment before and after treatment. The experimental results showed that nitrous oxide improved depressive symptoms better than placebo in terms of 17-Hamilton Depression Rating Scale score (HAMD-17). Statistical analysis based on ERP components showed that nitrous oxide-induced significant differences in amplitude and latency of N1, P1, N2, P2. In addition, increased brain functional connectivity was found after nitrous oxide treatment. And the change of network metrics has a significant correlation with decreased depressive symptoms. These findings may suggest that nitrous oxide improves depression symptoms for TRD by modifying brain function.
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Milton AL, Das RK, Merlo E. The challenge of memory destabilisation: From prediction error to prior expectations and biomarkers. Brain Res Bull 2023; 194:100-104. [PMID: 36708846 DOI: 10.1016/j.brainresbull.2023.01.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/22/2022] [Accepted: 01/24/2023] [Indexed: 01/26/2023]
Abstract
The re-ignition of memory reconsolidation research sparked by Karim Nader in the early 2000s led to great excitement that 'reconsolidation-based' interventions might be developed for mental health disorders such as post-traumatic stress disorder and substance use disorder. Two decades on, it is clear that reconsolidation-based interventions have been more challenging to translate to the clinic than initially thought. We argue that this challenge could be addressed with a better understanding of how prior expectations interact with information presented in a putative memory reactivation / cue reminder session, and through the identification of non-invasive biomarkers for memory destabilisation that would allow reminder sessions to be 'tuned' to enhance memory lability in an ad hoc manner.
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Affiliation(s)
- Amy L Milton
- Department of Psychology, University of Cambridge, Downing Site, Cambridge, UK.
| | - Ravi K Das
- Clinical Psychopharmacology Unit, University College London, London, UK
| | - Emiliano Merlo
- School of Psychology, University of Sussex, Brighton, UK
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5
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Visser RM, Henson RN, Holmes EA. A Naturalistic Paradigm to Investigate Postencoding Neural Activation Patterns in Relation to Subsequent Voluntary and Intrusive Recall of Distressing Events. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2022; 7:960-969. [PMID: 34454167 DOI: 10.1016/j.bpsc.2021.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/20/2021] [Accepted: 08/11/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND While neuroimaging has provided insights into the formation of episodic memories in relation to voluntary memory recall, less is known about neural mechanisms that cause memories to occur involuntarily, for example, as intrusive memories of trauma. Here, we investigated brain activity shortly after viewing distressing events as a function of whether memories for those events later intruded involuntarily. The postencoding period is particularly important because it is a period when clinical interventions could be applied. METHODS A total of 32 healthy volunteers underwent functional magnetic resonance imaging while viewing distressing film clips, interspersed with 5 minutes of awake (postencoding) rest. Voluntary memories of the films were assessed using free recall and verbal and visual recognition tests after a week, while intrusive (involuntary) memories were recorded in a diary throughout that week. RESULTS When analyzing functional magnetic resonance imaging responses related to watching the films, we replicated findings that those "hotspots" (salient moments within the films) that would later become intrusive memories elicited higher activation in parts of the brain's salience network. Surprisingly, while the postencoding persistence of multivoxel correlation structures associated with entire film clips predicted subsequent voluntary recall, there was no evidence that they predicted subsequent intrusions. CONCLUSIONS Results replicate findings regarding the formation of intrusive memories during encoding and extend findings regarding the consolidation of information in postencoding rest in relation to voluntary memory. While we provided a first step using a naturalistic paradigm, further research is needed to elucidate the role of postencoding neural processes in the development of intrusive memories.
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Affiliation(s)
- Renée M Visser
- Department of Clinical Psychology, University of Amsterdam, Amsterdam, The Netherlands.
| | - Richard N Henson
- Medical Research Council Cognition and Brain Sciences Unit and Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Emily A Holmes
- Department of Psychology, Uppsala University, Uppsala, Sweden; Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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6
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Accelerated forgetting of a trauma-like event in healthy men and women after a single dose of hydrocortisone. Transl Psychiatry 2022; 12:354. [PMID: 36045119 PMCID: PMC9433412 DOI: 10.1038/s41398-022-02126-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 08/15/2022] [Accepted: 08/18/2022] [Indexed: 11/23/2022] Open
Abstract
Posttraumatic stress disorder (PTSD) is characterised by dysregulated hypothalamic-pituitary-adrenal axis activity and altered glucocorticoid receptor sensitivity. Early treatment with glucocorticoids may reduce PTSD risk, although the effect of such treatment on the aetiologically critical step of traumatic-memory-formation remains unclear. Here we examine the effects of exogenous cortisol (hydrocortisone) in a preclinical model of PTSD, using a factorial (Drug × Sex), randomised-controlled, double-blind design. Healthy men and women (n = 120) were randomised to receive 30 mg oral hydrocortisone or matched placebo immediately after watching a stressful film. Effects on film-related intrusions were assessed acutely in the lab, and ecologically using daily memory diaries for one week. We found that participants receiving hydrocortisone showed a faster reduction in daily intrusion frequency. Voluntary memory was assessed once, at the end of the week, but was unaffected by hydrocortisone. Exploratory analyses indicated sex-dependent associations between intrusions and baseline estradiol and progesterone levels. In men receiving hydrocortisone, higher baseline estradiol levels were associated with fewer intrusions, whereas women exhibited the opposite pattern. By contrast, progesterone levels were positively associated with intrusions only in men treated with hydrocortisone. The findings suggest that hydrocortisone promotes an accelerated degradation of sensory-perceptual representations underlying traumatic intrusive memories. In addition, while sex alone was not an important moderator, the combination of sex and sex-hormone levels (especially estradiol) influenced hydrocortisone's effects on involuntary aversive memories. Future well-powered experimental studies may provide a basis for a precision-psychiatry approach to optimising early post-traumatic glucocorticoid treatments that target intrusive memories, based on individual endocrinological profiles.
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Jumaili WA, Trivedi C, Chao T, Kubosumi A, Jain S. The safety and efficacy of Ketamine NMDA receptor blocker as a therapeutic intervention for PTSD review of a randomized clinical trial. Behav Brain Res 2022; 424:113804. [PMID: 35181391 DOI: 10.1016/j.bbr.2022.113804] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 02/02/2022] [Accepted: 02/14/2022] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Posttraumatic stress disorder (PTSD) has long-lasting debilitating symptoms. PTSD causes a significant burden on healthcare workers and victims' families. The US Food Drug Administration (FDA) has approved only two Serotonin Selective Reuptake Inhibitors (SSRI), sertraline, and paroxetine as pharmacological interventions for PTSD. SSRI has a 50-60% response rate and up to 30% remission rate with a high relapse rate. Ketamine is an NMDA receptor blocker, has a rapid effective onset, a potent antidepressant with anti-suicidal, neuroprotective, and cognitive-enhancement properties. METHOD We retrieved randomized clinical trials (RCT) on PubMed, PubMed Central, and Medline Database of clinical trial studies until Jan/2022. We used the following keywords: "posttraumatic stress disorder. "AND "Ketamine." AND "Esketamine" AND "NMDA receptor antagonist" AND "treatment, pharmacological intervention, management. ". We used Medical Subject Heading [Mesh] Term for "ketamine" and "Esketamine" And "Receptors, N-Methyl-D-Aspartate" and "Stress Disorders, Post-Traumatic" and "Disease management.". RESULT All qualified five randomized clinical studies showed rapid and clear benefits of Ketamine infusion for PTSD symptoms resistant to conventional medications. The clinical improvements were evident in three of the four PTSD symptom categories, intrusions, avoidance, and negative alterations in cognitions and mood. In addition, Ketamine administration was safe well-tolerated, with transient dissociation as the main side effect reported. Ketamine infusion also positively affects comorbidities like chronic pain, alcohol use disorder, and major depression. CONCLUSION Ketamine showed fast, safe, highly effective pharmaceutical intervention for chronic PTSD symptoms. No correlation between ketamine potency and patient age, sex and/or body mass index. Further studies are needed to understand the appropriate therapeutic dose, onset, route of administration, duration of the treatment and comorbidity benefit.
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Affiliation(s)
- Wisam Al Jumaili
- Texas Tech University Health Science Center at Odessa/Permian Basin, Odessa, TX, USA.
| | - Chintan Trivedi
- Texas Tech University Health Science Center at Odessa/Permian Basin, Odessa, TX, USA
| | - Timothy Chao
- Texas Tech University Health Science Center at Odessa/Permian Basin, Odessa, TX, USA
| | - Aaron Kubosumi
- Texas Tech University Health Science Center at Odessa/Permian Basin, Odessa, TX, USA
| | - Shailesh Jain
- Texas Tech University Health Science Center at Odessa/Permian Basin, Odessa, TX, USA
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8
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Gillman MA. What is better for psychiatry: Titrated or fixed concentrations of nitrous oxide? Front Psychiatry 2022; 13:773190. [PMID: 36072452 PMCID: PMC9441863 DOI: 10.3389/fpsyt.2022.773190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Medication dosages are crucial-no single dose fits all. My paper compares the safety, scientific and practical applicability of fixed 25-50% concentrations of nitrous oxide (N2O) with the variable titrated concentrations of Psychotropic Analgesic N2O (PAN), as used in dentistry, and neuropsychiatry. A crucial difference is that PAN is always titrated, via an open circuit (nasal mask), to the minimum concentration (dose), which ensures full consciousness, cooperation, comfort and relaxation. With PAN, the goal is subject comfort, not dose. In contrast, fixed goal concentrations are usually given via relatively closed circuits (full facial mask/similar) without account for individual patient's dose-response. Hence, fixed concentrations, in N2O sensitive subjects, could result in unconsciousness and other adverse effects (nausea, vomiting, anxiety, aspiration, might occur; requiring an anaesthesiologist for patient safety. PAN is titrated using each subject's subjective and objective responses as the guide to the ideal concentration. Thus, when PAN is used, there is no fixed concentration even for a single subject, nor is an anaesthesiologist required. Furthermore, there is a greater scientific rationale for using PAN, because the receptor systems involved are better known, whilst those for fixed concentrations are not. The PAN or dental titration method has been safely used in general dentistry for over 70 years and as an investigative, diagnostic and therapeutic tool for neuropsychiatry for over 40 years. Clinical applications include substance abuse detoxification, ameliorating depression, and investigations of schizophrenia, human orgasm, pain perception and basic neuroscience. By contrast, the experience with fixed doses in psychiatry is limited.
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Affiliation(s)
- Mark A Gillman
- Directorate, South African Brain Research Institute, Johannesburg, South Africa
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9
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Quach DF, de Leon VC, Conway CR. Nitrous Oxide: an emerging novel treatment for treatment-resistant depression. J Neurol Sci 2021; 434:120092. [PMID: 34953347 DOI: 10.1016/j.jns.2021.120092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 12/03/2021] [Accepted: 12/12/2021] [Indexed: 10/19/2022]
Abstract
Stemming from the results of the historic STAR-D trial, it is evident that a significant subset of individuals (20-25%) with major depressive disorder (MDD) do not respond to conventional antidepressant medications. As a result, an emphasis has been placed on the development of novel therapeutics for MDD over the last two decades. Recently, substantial research efforts have been focused on the use of ketamine as an antidepressant whose mechanism of action is via the N-methyl-d-aspartate (NMDA) receptor. Another potential therapeutic compound of interest is nitrous oxide, which has been utilized for more than a century in multiple fields of medicine for its analgesic and anesthetic properties. Recent clinical studies suggest that nitrous oxide may be effective for treatment-resistant depression. In this review, we will discuss the administration of nitrous oxide as a psychiatric intervention, current use in psychiatry, putative mechanisms of action, and future directions highlighting knowledge gaps and other potential utilities in the field of psychiatry.
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Affiliation(s)
- Darin F Quach
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States of America
| | - Victoria C de Leon
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States of America
| | - Charles R Conway
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, United States of America.
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10
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Nagele P, Palanca BJ, Gott B, Brown F, Barnes L, Nguyen T, Xiong W, Salloum NC, Espejo GD, Lessov-Schlaggar CN, Jain N, Cheng WWL, Komen H, Yee B, Bolzenius JD, Janski A, Gibbons R, Zorumski CF, Conway CR. A phase 2 trial of inhaled nitrous oxide for treatment-resistant major depression. Sci Transl Med 2021; 13:13/597/eabe1376. [PMID: 34108247 DOI: 10.1126/scitranslmed.abe1376] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 11/19/2020] [Accepted: 04/23/2021] [Indexed: 12/26/2022]
Abstract
Nitrous oxide at 50% inhaled concentration has been shown to improve depressive symptoms in patients with treatment-resistant major depression (TRMD). Whether a lower concentration of 25% nitrous oxide provides similar efficacy and persistence of antidepressant effects while reducing the risk of adverse side effects is unknown. In this phase 2 clinical trial (NCT03283670), 24 patients with severe TRMD were randomly assigned in a crossover fashion to three treatments consisting of a single 1-hour inhalation with (i) 50% nitrous oxide, (ii) 25% nitrous oxide, or (iii) placebo (air/oxygen). The primary outcome was the change on the Hamilton Depression Rating Scale (HDRS-21). Whereas nitrous oxide significantly improved depressive symptoms versus placebo (P = 0.01), there was no difference between 25 and 50% nitrous oxide (P = 0.58). The estimated differences between 25% and placebo were -0.75 points on the HDRS-21 at 2 hours (P = 0.73), -1.41 points at 24 hours (P = 0.52), -4.35 points at week 1 (P = 0.05), and -5.19 points at week 2 (P = 0.02), and the estimated differences between 50% and placebo were -0.87 points at 2 hours (P = 0.69), -1.93 points at 24 hours (P = 0.37), -2.44 points at week 1 (P = 0.25), and -7.00 points at week 2 (P = 0.001). Adverse events declined substantially with dose (P < 0.001). These results suggest that 25% nitrous oxide has comparable efficacy to 50% nitrous oxide in improving TRMD but with a markedly lower rate of adverse effects.
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Affiliation(s)
- Peter Nagele
- Department of Anesthesia and Critical Care, University of Chicago, Chicago, IL 60637, USA.
| | - Ben J Palanca
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Britt Gott
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Frank Brown
- Department of Anesthesia and Critical Care, University of Chicago, Chicago, IL 60637, USA
| | - Linda Barnes
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Thomas Nguyen
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Willa Xiong
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Naji C Salloum
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Gemma D Espejo
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | | - Nisha Jain
- Department of Anesthesia and Critical Care, University of Chicago, Chicago, IL 60637, USA
| | - Wayland W L Cheng
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Helga Komen
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Branden Yee
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jacob D Bolzenius
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alvin Janski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Robert Gibbons
- Center for Health Statistics, University of Chicago, Chicago, IL 60637, USA
| | - Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Charles R Conway
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO 63110, USA
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11
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Kamboj SK, Zhao H, Troebinger L, Piazza G, Cawley E, Hennessy V, Iskandar G, Das RK. Rewarding Subjective Effects of the NMDAR Antagonist Nitrous Oxide (Laughing Gas) Are Moderated by Impulsivity and Depressive Symptoms in Healthy Volunteers. Int J Neuropsychopharmacol 2021; 24:551-561. [PMID: 33667308 PMCID: PMC8299821 DOI: 10.1093/ijnp/pyab009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/02/2021] [Accepted: 02/23/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Nitrous oxide (N2O) is an anesthetic gas with both therapeutic and abuse potential. Because N2O is an NMDA receptor (NMDAR) antagonist, its effects are expected to resemble those of the prototypical NMDAR antagonist, ketamine. In this study, we examined the subjective rewarding effects of N2O using measures previously employed in studies of ketamine. We also tested for moderation of these effects by bipolar phenotype, depressive symptoms, and impulsivity. METHODS Healthy volunteers were randomly assigned to either 50% N2O (n = 40) or medical air (n = 40). Self-reported rewarding (liking and wanting), and alcohol-like effects were assessed pre-, peri- and post inhalation. RESULTS Effect sizes for the various rewarding/alcohol-like effects of N2O were generally similar to those reported in studies of moderate-dose ketamine. Impulsivity moderated the subjective reinforcing (liking) effects of inhaled gas, while depressive symptoms moderated motivational (wanting [more]) effects. However, depression and impulsivity had opposite directional influences, such that higher impulsivity was associated with higher N2O liking, and higher depression, with lower N2O wanting. CONCLUSION To the extent that static (versus longitudinal) subjective rewarding effects are a reliable indicator of future problematic drug use, our findings suggests that impulsivity and depression may predispose and protect, respectively, against N2O abuse. Future studies should examine if these moderators are relevant for other NMDAR antagonists, including ketamine, and novel ketamine-like therapeutic and recreational drugs. Similarities between moderate-dose N2O and moderate-dose ketamine in the intensity of certain subjective effects suggest that N2O may, at least to some extent, serve as substitute for ketamine as a safe and easily implemented experimental tool for probing reward-related NMDAR function and dysfunction in humans.
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Affiliation(s)
- Sunjeev K Kamboj
- Clinical Psychopharmacology Unit, Research Department Clinical Educational and Health Psychology, University College London, London, United Kingdom,Correspondence: Sunjeev K. Kamboj, DClinPsy, PhD, ()
| | - Hannah Zhao
- Clinical Psychopharmacology Unit, Research Department Clinical Educational and Health Psychology, University College London, London, United Kingdom
| | - Luzia Troebinger
- Clinical Psychopharmacology Unit, Research Department Clinical Educational and Health Psychology, University College London, London, United Kingdom
| | - Giulia Piazza
- Clinical Psychopharmacology Unit, Research Department Clinical Educational and Health Psychology, University College London, London, United Kingdom
| | - Emma Cawley
- Clinical Psychopharmacology Unit, Research Department Clinical Educational and Health Psychology, University College London, London, United Kingdom
| | - Vanessa Hennessy
- Clinical Psychopharmacology Unit, Research Department Clinical Educational and Health Psychology, University College London, London, United Kingdom
| | - Georges Iskandar
- Department of Anaesthesia and Perioperative Medicine, University College London Hospital, London, United Kingdom
| | - Ravi K Das
- Clinical Psychopharmacology Unit, Research Department Clinical Educational and Health Psychology, University College London, London, United Kingdom
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12
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Deforges C, Stuijfzand S, Noël Y, Robertson M, Breines Simonsen T, Eberhard-Gran M, Garthus-Niegel S, Horsch A. The relationship between early administration of morphine or nitrous oxide gas and PTSD symptom development. J Affect Disord 2021; 281:557-566. [PMID: 33421836 DOI: 10.1016/j.jad.2020.12.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND Posttraumatic Stress Disorder (PTSD) is a debilitating mental health disorder. Certain drugs, such as morphine and nitrous oxide gas (N2O), are administered to individuals who just experienced a traumatic event (e.g., soldiers, injured civilians). It is therefore crucial to understand if they incidentally affect PTSD symptom development. Furthermore, such observations could pave the way for the development of pharmacological prevention strategies of PTSD. METHODS In this prospective population-based cohort study (n = 2,070), we examined the relationship between morphine or N2O administration during childbirth, and subsequent childbirth-related PTSD symptoms at eight weeks postpartum. Pain during labour, prior PTSD symptoms, and birth medical severity were included as covariates in the analyses. RESULTS In women who developed PTSD symptoms, N2O administration during childbirth predicted reduced PTSD symptom severity (p < .001, small to medium effect size). A similar tendency was observed for morphine, but was not significant (p < .065, null to small effect size). Both drugs predicted increased PTSD symptoms when combined with severe pain during labour. LIMITATIONS This study was observational, thus drug administration was not randomised. Additionally, PTSD symptoms were self-reported. CONCLUSIONS Peritraumatic N2O administration may reduce subsequent PTSD symptom severity and thus be a potential avenue for PTSD secondary prevention. This might also be the case for morphine. However, the role of severe peritraumatic pain in context of drug administration deserves further investigation.
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Affiliation(s)
- Camille Deforges
- Institute of Higher Education and Research in Healthcare (IUFRS), University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland.
| | - Suzannah Stuijfzand
- Institute of Higher Education and Research in Healthcare (IUFRS), University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland.
| | | | - Moira Robertson
- Woman-Mother-Child Department, Lausanne University Hospital, Lausanne, Switzerland.
| | - Tone Breines Simonsen
- HØKH - Health Services Research Centre, Akershus University Hospital, Lørenskog, Norway; Department of Obstetrics and Gynaecology, Akershus University Hospital, Lørenskog, Norway.
| | - Malin Eberhard-Gran
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Norwegian National Advisory Unit on Women's Health, Women and Children's Division, Oslo University Hospital, Oslo, Norway.
| | - Susan Garthus-Niegel
- Department of Medicine, Medical School Hamburg, Hamburg, Germany; Department of Child Health and Development, Norwegian Institute of Public Health, Oslo, Norway; Institute and Policlinic of Occupational and Social Medicine, Technische Universität Dresden, Dresden, Germany.
| | - Antje Horsch
- Institute of Higher Education and Research in Healthcare (IUFRS), University of Lausanne and Lausanne University Hospital, Lausanne, Switzerland; Woman-Mother-Child Department, Lausanne University Hospital, Lausanne, Switzerland.
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13
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Singh L, Espinosa L, Ji JL, Moulds ML, Holmes EA. Developing thinking around mental health science: the example of intrusive, emotional mental imagery after psychological trauma. Cogn Neuropsychiatry 2020; 25:348-363. [PMID: 32847486 DOI: 10.1080/13546805.2020.1804845] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION One route to advancing psychological treatments is to harness mental health science, a multidisciplinary approach including individuals with lived experience and end users (e.g., Holmes, E. A., Craske, M. G., & Graybiel, A. M. (2014). Psychological treatments: A call for mental-health science. Nature, 511(7509), 287-289. doi:10.1038/511287a). While early days, we here illustrate a line of research explored by our group-intrusive imagery-based memories after trauma. METHOD/RESULTS We illustrate three possible approaches through which mental health science may stimulate thinking around psychological treatment innovation. First, focusing on single/specific target symptoms rather than full, multifaceted psychiatric diagnoses (e.g., intrusive trauma memories rather than all of posttraumatic stress disorder). Second, investigating mechanisms that can be modified in treatment (treatment mechanisms), rather than those which cannot (e.g., processes only linked to aetiology). Finally, exploring novel ways of delivering psychological treatment (peer-/self-administration), given the prevalence of mental health problems globally, and the corresponding need for effective interventions that can be delivered at scale and remotely for example at times of crisis (e.g., current COVID-19 pandemic). CONCLUSIONS These three approaches suggest options for potential innovative avenues through which mental health science may be harnessed to recouple basic and applied research and transform treatment development.
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Affiliation(s)
- Laura Singh
- Department of Psychology, Uppsala University, Uppsala, Sweden
| | - Lisa Espinosa
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Julie L Ji
- School of Psychological Science, The University of Western Australia, UWA Perth, Australia
| | - Michelle L Moulds
- School of Psychology, The University of New South Wales, UNSW Sydney, Australia
| | - Emily A Holmes
- Department of Psychology, Uppsala University, Uppsala, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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14
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Varias A, van Roessel P, Parsiani M, Filippou-Frye M, Neylan TC, Nagele P, Yesavage J, Clark JD, Rodriguez CI. Does Nitrous Oxide Help Veterans With Posttraumatic Stress Disorder? A Case Series. J Clin Psychiatry 2020; 81:20l13393. [PMID: 32609959 PMCID: PMC8218879 DOI: 10.4088/jcp.20l13393] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Andrea Varias
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
| | - Peter van Roessel
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
| | - Maryam Parsiani
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Maria Filippou-Frye
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
| | - Thomas C. Neylan
- San Francisco Veterans Affairs Medical Center, San Francisco, California,Departments of Psychiatry and Neurology, University of California San Francisco, San Francisco, California
| | - Peter Nagele
- Department of Anesthesia and Critical Care, University of Chicago Medicine, Chicago, Illinois
| | - Jerome Yesavage
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California,Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - J. David Clark
- Veterans Affairs Palo Alto Health Care System, Palo Alto, California,Department of Anesthesiology Perioperative and Pain Medicine, Stanford University, Stanford, California
| | - Carolyn I. Rodriguez
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California,Veterans Affairs Palo Alto Health Care System, Palo Alto, California
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15
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Dimick MK, Omrin D, MacIntosh BJ, Mitchell RHB, Riegert D, Levitt A, Schaffer A, Belo S, Iazzetta J, Detzler G, Choi M, Choi S, Orser BA, Goldstein BI. Nitrous oxide as a putative novel dual-mechanism treatment for bipolar depression: Proof-of-concept study design and methodology. Contemp Clin Trials Commun 2020; 19:100600. [PMID: 32637725 PMCID: PMC7327241 DOI: 10.1016/j.conctc.2020.100600] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/10/2020] [Accepted: 06/21/2020] [Indexed: 12/23/2022] Open
Abstract
Introduction Depressive symptoms predominate in the course of bipolar disorder (BD) and there is an urgent need to evaluate novel application of repurposed compounds that act on pre-specified treatment targets. Several lines of reasoning suggest that nitrous oxide (N2O) is an ideal medication to study as a potential treatment and as a strategy to identify the underlying pathophysiology of bipolar depression. N2O is a potent cerebral vasodilator and there is compelling evidence of reduced frontal cerebral blood flow (CBF; i.e. hypoperfusion) in depression. Therefore, N2O may increase CBF and thereby improve symptoms of depression. The goal of this randomized, double-blind trial is to study the effect of a single administration of N2O versus the active comparator midazolam on mood and CBF in adults with treatment-resistant bipolar depression. Methods Participants with BD-I/-II currently experiencing a major depressive episode will be randomized to one of two conditions (n = 20/group): 1) inhaled N2O plus intravenous saline, or 2) inhaled room air plus intravenous midazolam. Montgomery-Asberg Depression Rating Scale scores will serve as the primary endpoint. CBF will be measured via arterial spin labelling magnetic resonance imaging. Conclusions N2O is a potential novel treatment for bipolar depression, as it causes cerebral vasodilation. This proof-of-concept study will provide valuable information regarding the acute impact of N2O on mood and on CBF. If N2O proves to be efficacious in future larger-scale trials, its ubiquity, safety, low cost, and ease of use suggest that it has great potential to become a game-changing acute treatment for bipolar depression.
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Affiliation(s)
- Mikaela K Dimick
- Pharmacology and Toxicology Department, University of Toronto, Toronto, Ontario, Canada.,Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Danielle Omrin
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Bradley J MacIntosh
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Rachel H B Mitchell
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Daniel Riegert
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
| | - Anthony Levitt
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Ayal Schaffer
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Susan Belo
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
| | - John Iazzetta
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Pharmacy Department, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | | | - Mabel Choi
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
| | - Stephen Choi
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
| | - Beverley A Orser
- Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
| | - Benjamin I Goldstein
- Pharmacology and Toxicology Department, University of Toronto, Toronto, Ontario, Canada.,Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
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16
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Kamboj SK, Gong AT, Sim Z, Rashid AA, Baba A, Iskandar G, Das RK, Curran HV. Reduction in the occurrence of distressing involuntary memories following propranolol or hydrocortisone in healthy women. Psychol Med 2020; 50:1148-1155. [PMID: 31084640 DOI: 10.1017/s0033291719001028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Pharmacological treatments targeting the neuroendocrine stress response may hold special promise in secondary prevention of posttraumatic stress disorder (PTSD). However, findings from clinical trials have been inconsistent and the efficacy of specific drugs, their temporal window of efficacy, effective doses and the characteristics of likely treatment responders remain unclear. METHOD Using an experimental human model of distressing involuntary memory formation, we compare the effects of two drugs that have theoretical or empirical support as secondary preventive agents in PTSD. Eighty-eight healthy women (average age: 23.5 years) received oral propranolol (80 mg), hydrocortisone (30 mg), or matched placebo immediately after viewing a 'trauma film'. They then completed daily, time-stamped intrusion diaries for 1 week, at the end of which, voluntary memory was tested. RESULTS While neither drug affected voluntary memory for the trauma narrative, propranolol treatment was associated with 42% fewer, and hydrocortisone with 55% fewer intrusions across the week, relative to placebo. Additionally, propranolol reduced general trauma-like symptoms, and post-drug cortisol levels were negatively correlated with intrusion frequency in the hydrocortisone group. CONCLUSIONS Overall, this study shows substantial reductions in intrusive memories and preserved voluntary narrative-declarative memory following either propranolol or hydrocortisone in an experimental model of psychological trauma. As such, despite some inconsistencies in clinical trials, our findings support continued investigation of propranolol and hydrocortisone as secondary preventive agents for re-experiencing symptoms of PTSD. The findings also suggest that it is critical for future research to identify the conditions governing the preventive efficacy of these drugs in PTSD.
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Affiliation(s)
| | - An Tong Gong
- Clinical Psychopharmacology Unit, UCL, LondonWC1E 6BT, UK
| | - ZhiHui Sim
- Clinical Psychopharmacology Unit, UCL, LondonWC1E 6BT, UK
| | | | - Ami Baba
- Clinical Psychopharmacology Unit, UCL, LondonWC1E 6BT, UK
| | - Georges Iskandar
- Department of Anaesthesia and Perioperative Medicine, UCLH, London, UK
| | - Ravi K Das
- Clinical Psychopharmacology Unit, UCL, LondonWC1E 6BT, UK
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17
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Lau-Zhu A, Henson RN, Holmes EA. Intrusive memories and voluntary memory of a trauma film: Differential effects of a cognitive interference task after encoding. J Exp Psychol Gen 2019; 148:2154-2180. [PMID: 31021150 PMCID: PMC7116494 DOI: 10.1037/xge0000598] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Methods to reduce intrusive memories (e.g., of traumatic events) should ideally spare voluntary memory for the same event (e.g., to report on the event in court). Single-trace memory accounts assume that interfering with a trace should impact both its involuntary and voluntary expressions, whereas separate-trace accounts assume these two can dissociate, allowing for selective interference. This possibility was investigated in 3 experiments. Nonclinical participants viewed a trauma film followed by an interference task (Tetris game-play after reminder cues). Next, memory for the film was assessed with various measures. The interference task reduced the number of intrusive memories (diary-based, Experiments 1 and 2), but spared performance on well-matched measures of voluntary retrieval-free recall (Experiment 1) and recognition (Experiments 1 and 2)-challenging single-trace accounts. The interference task did not affect other measures of involuntary retrieval-perceptual priming (Experiment 1) or attentional bias (Experiment 2). However, the interference task did reduce the number of intrusive memories in a laboratory-based vigilance-intrusion task (Experiments 2 and 3), irrespective of concurrent working memory load during intrusion retrieval (Experiment 3). Collectively, results reveal a robust dissociation between intrusive and voluntary memories, having ruled out key methodological differences between how these two memory expressions are assessed, namely cue overlap (Experiment 1), attentional capture (Experiment 2), and retrieval load (Experiment 3). We argue that the inability of these retrieval factors to explain the selective interference is more compatible with separate-trace than single-trace accounts. Further theoretical developments are needed to account for this clinically important distinction between intrusive memories and their voluntary counterpart. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Affiliation(s)
- Alex Lau-Zhu
- Medical Research Council Cognition and Brain Sciences Unit
| | | | - Emily A Holmes
- Medical Research Council Cognition and Brain Sciences Unit
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18
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Iyadurai L, Visser RM, Lau-Zhu A, Porcheret K, Horsch A, Holmes EA, James EL. Intrusive memories of trauma: A target for research bridging cognitive science and its clinical application. Clin Psychol Rev 2019; 69:67-82. [PMID: 30293686 PMCID: PMC6475651 DOI: 10.1016/j.cpr.2018.08.005] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 08/17/2018] [Accepted: 08/17/2018] [Indexed: 01/01/2023]
Abstract
Intrusive memories of a traumatic event can be distressing and disruptive, and comprise a core clinical feature of post-traumatic stress disorder (PTSD). Intrusive memories involve mental imagery-based impressions that intrude into mind involuntarily, and are emotional. Here we consider how recent advances in cognitive science have fueled our understanding of the development and possible treatment of intrusive memories of trauma. We conducted a systematic literature search in PubMed, selecting articles published from 2008 to 2018 that used the terms "trauma" AND ("intrusive memories" OR "involuntary memories") in their abstract or title. First, we discuss studies that investigated internal (neural, hormonal, psychophysiological, and cognitive) processes that contribute to intrusive memory development. Second, we discuss studies that targeted these processes using behavioural/pharmacological interventions to reduce intrusive memories. Third, we consider possible clinical implications of this work and highlight some emerging research avenues for treatment and prevention, supplemented by new data to examine some unanswered questions. In conclusion, we raise the possibility that intrusive memories comprise an alternative, possibly more focused, target in translational research endeavours, rather than only targeting overall symptoms of disorders such as PTSD. If so, relatively simple approaches could help to address the need for easy-to-deliver, widely-scalable trauma interventions.
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Affiliation(s)
| | - Renée M Visser
- MRC Cognition and Brain Sciences Unit, University of Cambridge, UK; University of Amsterdam, Department of Psychology, Amsterdam, The Netherlands
| | - Alex Lau-Zhu
- MRC Cognition and Brain Sciences Unit, University of Cambridge, UK; Kings College London, Institute of Psychiatry, Psychology and Neuroscience, Social, Genetic and Developmental Psychiatry Centre, London, UK
| | - Kate Porcheret
- University of Oxford, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, Oxford, UK
| | - Antje Horsch
- Lausanne University Hospital, Woman-Mother-Child Department, Lausanne, Switzerland; Institute of Higher Education and Research in Healthcare, University of Lausanne, Lausanne University Hospital, Lausanne, Switzerland
| | - Emily A Holmes
- Karolinska Institutet, Division of Psychology, Department of Clinical Neuroscience, Stockholm, Sweden
| | - Ella L James
- MRC Cognition and Brain Sciences Unit, University of Cambridge, UK
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19
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Buhre W, Disma N, Hendrickx J, DeHert S, Hollmann MW, Huhn R, Jakobsson J, Nagele P, Peyton P, Vutskits L. European Society of Anaesthesiology Task Force on Nitrous Oxide: a narrative review of its role in clinical practice. Br J Anaesth 2019; 122:587-604. [PMID: 30916011 DOI: 10.1016/j.bja.2019.01.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 12/26/2018] [Accepted: 01/13/2019] [Indexed: 12/12/2022] Open
Abstract
Nitrous oxide (N2O) is one of the oldest drugs still in use in medicine. Despite its superior pharmacokinetic properties, controversy remains over its continued use in clinical practice, reflecting in part significant improvements in the pharmacology of other anaesthetic agents and developing awareness of its shortcomings. This narrative review describes current knowledge regarding the clinical use of N2O based on a systematic and critical analysis of the available scientific literature. The pharmacological properties of N2O are reviewed in detail along with current evidence for the indications and contraindications of this drug in specific settings, both in perioperative care and in procedural sedation. Novel potential applications for N2O for the prevention or treatment of chronic pain and depression are also discussed. In view of the available evidence, we recommend that the supply of N2O in hospitals be maintained while encouraging its economic delivery using modern low flow delivery systems. Future research into its potential novel applications in prevention or treatment of chronic conditions should be pursued to better identify its role place in the developing era of precision medicine.
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Affiliation(s)
- Wolfgang Buhre
- Department of Anesthesiology and Pain Medicine, Maastricht University Medical Center, University of Maastricht, Maastricht, the Netherlands
| | - Nicola Disma
- Department of Anesthesia, Istituto Giannina Gaslini, Genoa, Italy
| | - Jan Hendrickx
- Department of Anesthesiology, Onze-Lieve-Vrouwziekenhuis Hospital Aalst, Aalst, Belgium
| | - Stefan DeHert
- Department of Anesthesiology and Perioperative Medicine, University Hospital Ghent, Ghent, Belgium
| | - Markus W Hollmann
- Department of Anesthesiology, Amsterdam University Medical Center (AUMC), AMC, University of Amsterdam, Amsterdam, the Netherlands.
| | - Ragnar Huhn
- Department of Anesthesiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Jan Jakobsson
- Department of Anesthesiology and Intensive Care, Institution for Clinical Science, Karolinska Institute, Danderyds University Hospital, Danderyd, Sweden
| | - Peter Nagele
- Department of Anesthesia and Critical Care, University of Chicago Medicine, Chicago, IL, USA
| | - Philip Peyton
- Department of Anaesthesia, Austin Health, and Anaesthesia Perioperative and Pain Medicine Unit, Melbourne Medical School, University of Melbourne, Melbourne, Australia
| | - Laszlo Vutskits
- Department of Anesthesiology, Pharmacology and Intensive Care, University Hospitals Geneva, Genève, Switzerland
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20
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Rattel JA, Grünberger LM, Reichenberger J, Liedlgruber M, Miedl SF, Blechert J, Wilhelm FH. Frequency of Intrusions and Appraisal of Related Distress After Analogue Trauma: A Comparative Ecological Momentary Assessment Methods Study. COGNITIVE THERAPY AND RESEARCH 2019; 43:174-184. [PMID: 30880849 PMCID: PMC6420051 DOI: 10.1007/s10608-018-9941-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Intrusive thoughts, images, and their appraisal remain difficult to study despite their clinical relevance. Clinical studies typically used time-based (frequency and distress per observation period), while analogue studies mainly used event-based (report upon occurrence) assessment. A comparison of intrusion frequency, distress appraisal, compliance, and reactivity across different assessments is mostly lacking, particularly with regard to analogue research. Here, intrusions were induced via aversive films and assessed by a smart phone application for 4 days. Three sampling modes were compared by randomizing participants to one of three conditions: either one, or five time-based daily prompts, or event-based assessment. At the end of the study, all participants reported intrusions once again in a retrospective summary assessment. Results indicate that intrusions and their distress decayed over a few days. The three assessments did not differ in intrusion frequency, distress appraisal, compliance (generally high), reactivity (generally low), or retrospective summary assessment. Across groups, the more aversive and arousing participants rated the film clips and the more reactivity to the electronic-diary assessment they reported, the more intrusive memories they had; assessment modes did not differ on this. Thus, no general differences were found between electronic-diary assessment modes for analogue intrusions, giving researchers flexibility for tailoring ecological momentary assessment to specific study aims.
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Affiliation(s)
- Julina A. Rattel
- Department of Psychology, Division for Clinical Psychology, Psychotherapy and Health Psychology, University of Salzburg, Salzburg, Austria
| | - Lisa M. Grünberger
- Department of Psychology, Division for Clinical Psychology, Psychotherapy and Health Psychology, University of Salzburg, Salzburg, Austria
| | - Julia Reichenberger
- Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
- Department of Psychology, University of Salzburg, Salzburg, Austria
| | - Michael Liedlgruber
- Department of Psychology, Division for Clinical Psychology, Psychotherapy and Health Psychology, University of Salzburg, Salzburg, Austria
| | - Stephan F. Miedl
- Department of Psychology, Division for Clinical Psychology, Psychotherapy and Health Psychology, University of Salzburg, Salzburg, Austria
| | - Jens Blechert
- Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
- Department of Psychology, University of Salzburg, Salzburg, Austria
| | - Frank H. Wilhelm
- Department of Psychology, Division for Clinical Psychology, Psychotherapy and Health Psychology, University of Salzburg, Salzburg, Austria
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21
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Sopp MR, Brueckner AH, Michael T. The Prospective Influence of Trait Alexithymia on Intrusive Memories: What Is the Role of Emotional Recognition Memory? Front Psychol 2019; 9:2642. [PMID: 30670997 PMCID: PMC6331440 DOI: 10.3389/fpsyg.2018.02642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 12/10/2018] [Indexed: 11/29/2022] Open
Abstract
Posttraumatic stress disorder (PTSD) is often considered to be a disorder of memory as patients suffer from fragmented uncontrollable memories (intrusions) whilst experiencing difficulties in intentionally retrieving details of the traumatic event. Recent research suggests that trait-related deficits in the identification of emotional states (alexithymia) may impact emotional memory processes in a way that promotes intrusion formation in PTSD. Therefore, we investigated the influence of alexithymia on intrusive re-experiencing and emotional recognition memory in a prospective analog study. Twenty-six healthy participants took part in a laboratory experiment, which combined two independent paradigms. Participants were exposed to a traumatic film (first session) and completed an episodic memory task comprising neutral and emotional stimuli (second session). In between sessions, participants recorded intrusive memories of the film. Individuals with higher trait alexithymia (HTA) reported an increased number of intrusions on the day of film presentation. Moreover, analyses of memory performance revealed a negative correlation between alexithymia and emotional recognition memory. Further analyses suggest that reduced emotional recognition memory, as evident in individuals with HTA, may, in turn, be associated with enhanced intrusive re-experiencing. As such, the current findings provide first indications regarding the role of alexithymia in emotional learning and PTSD. Future studies should further investigate these associations as well as potential implications for the treatment of PTSD.
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Affiliation(s)
- M. Roxanne Sopp
- Division of Clinical Psychology and Psychotherapy, Department of Psychology, Saarland University, Saarbrücken, Germany
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22
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Monfils MH, Holmes EA. Memory boundaries: opening a window inspired by reconsolidation to treat anxiety, trauma-related, and addiction disorders. Lancet Psychiatry 2018; 5:1032-1042. [PMID: 30385214 DOI: 10.1016/s2215-0366(18)30270-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 01/12/2023]
Abstract
Pioneering research over the past two decades has shown that memories are far more malleable than we once thought, thereby highlighting the potential for new clinical avenues for treatment of psychopathology. We first briefly review the historical foundation of memory reconsolidation-a concept that refers to hypothetical processes that occur when a memory is retrieved and restored. Then, we provide an overview of the basic research on memory reconsolidation that has been done with humans and other animals, focusing on models of fear, anxiety-related disorders, and addiction, from the perspective that they all involve disorders of memory. This basic research has fuelled early stage developments of novel treatment techniques. More specifically, we consider behavioural interventions inspired by reconsolidation updating, namely retrieval-extinction techniques. We discuss the set of principles that would be needed for memory modifications within a putative reconsolidation time window, and review research that employs reconsolidation-based strategies with clinical populations. We conclude by highlighting current pitfalls and controversies surrounding the use of reconsolidation-based approaches, but end on an optimistic note for clinical research going forward. Despite the challenges, we believe that drawing on ideas from psychological science can help open up treatment innovation.
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Affiliation(s)
- Marie H Monfils
- Department of Psychology, Institute for Mental Health Research, University of Texas at Austin, Austin, TX, USA.
| | - Emily A Holmes
- Division of Psychology, Department for Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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23
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Das RK, Walsh K, Hannaford J, Lazzarino AI, Kamboj SK. Nitrous oxide may interfere with the reconsolidation of drinking memories in hazardous drinkers in a prediction-error-dependent manner. Eur Neuropsychopharmacol 2018; 28:828-840. [PMID: 29887289 DOI: 10.1016/j.euroneuro.2018.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/29/2018] [Accepted: 05/17/2018] [Indexed: 12/16/2022]
Abstract
Weakening drinking-related reward memories by blocking their reconsolidation is a potential novel strategy for treating alcohol use disorders. However, few viable pharmacological options exist for reconsolidation interference in humans. We therefore examined whether the NMDA receptor antagonising gas, Nitrous Oxide (N2O) could reduce drinking by preventing the post-retrieval restabilisation of alcohol memories in a group of hazardous drinkers. Critically, we focussed on whether prediction error (PE; a key determinant of reconsolidation) was experienced at retrieval. Sixty hazardous drinkers were randomised to one of three groups that retrieved alcohol memories either with negative PE (Retrieval + PE), no PE (Retrieval no PE) or non-alcohol memory retrieval with PE (No-retrieval +PE). All participants then inhaled 50% N2O for 30 min. The primary outcome was change in beer consumption and alcohol cue-driven urge to drink from the week preceding manipulation (baseline) to the week following manipulation (test). The manipulation did not affect drinking following the intended retrieval+/- PE conditions However, a manipulation check, using a measure of subjective surprise, revealed that the group-level manipulation did not achieve the intended differences in PE at retrieval. Assessment of outcomes according to whether alcohol-relevant PE was actually experienced at retrieval, showed N2O produced reductions in drinking in a retrieval and PE-dependent fashion. These preliminary findings highlight the importance of directly testing assumptions about memory reactivation procedures in reconsolidation research and suggest that N2O should be further investigated as a potential reconsolidation-blocking agent.
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Affiliation(s)
- R K Das
- Clinical Psychopharmacology Unit, University College London, 1-19 Torrington Place, London WC1E 7HB, United Kingdom; Educational Psychology, Clinical, Educational and Health Psychology, University College London, 26 Bedford Way, London WC1H 0AP, United Kingdom.
| | - K Walsh
- Clinical Psychopharmacology Unit, University College London, 1-19 Torrington Place, London WC1E 7HB, United Kingdom
| | - J Hannaford
- Clinical Psychopharmacology Unit, University College London, 1-19 Torrington Place, London WC1E 7HB, United Kingdom
| | - A I Lazzarino
- Department of Epidemiology and Public Health, UCL, 1-19 Torrington Place, London WC1E 7HB, United Kingdom
| | - S K Kamboj
- Clinical Psychopharmacology Unit, University College London, 1-19 Torrington Place, London WC1E 7HB, United Kingdom
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Marks EH, Franklin AR, Zoellner LA. Can't get it out of my mind: A systematic review of predictors of intrusive memories of distressing events. Psychol Bull 2018; 144:584-640. [PMID: 29553763 PMCID: PMC5938103 DOI: 10.1037/bul0000132] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Intrusive memories, when persistent and distressing, are theorized to underlie a range of transdiagnostic psychological symptoms and associated impairment. However, little is known about factors predicting the development and persistence of intrusive memories. The aim of this systematic review is to evaluate the literature on pre-event, event-based, and post-event predictors of intrusive memories. A systematic review was conducted, searching for studies that examined intrusive, event-based memories. One hundred and six articles were identified from PsycInfo, PubMed, and Medline databases. Experimental and prospective studies with clinical (N = 14) and nonclinical (N = 92) samples were critically reviewed, provided the inclusion of an analogue stressor with nonclinical samples, and that intrusive memories frequency and/or distress were assessed as primary dependent variables. Pre-existing psychopathology and pre-event appraisal style appear to predict intrusive memories (small to medium effects), whereas trait dissociation did not predict intrusive memories. Of studies examining event-based predictors, higher data-driven processing appears to predict intrusive memories with generally large effects. Post-event negative appraisals consistently predicted intrusive memories (medium to large effects), and preliminary evidence suggests higher post-event conceptual processing predicting fewer intrusive memories. This review synthesizes findings regarding a broad range of pre-event, event-based, and post-event factors that may influence the development of intrusive memories. Methodological issues of current paradigms and the lack of emphasis on memory retrieval processes limit our understanding of what predicts intrusive memory persistence. These limitations are particularly important given that individuals typically seek treatment for distressing intrusive memories once a memory has been fully consolidated, where retrieval processes are of utmost importance. (PsycINFO Database Record
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Abstract
Nitrous oxide (laughing gas) has shown early promise as a rapidly acting antidepressant in patients with treatment-resistant major depression and is currently investigated in several clinical trials. Because nitrous oxide is rarely administered outside operating rooms or dental practices, most psychiatrists are not familiar with how nitrous oxide is administered in a medical setting and what regulations guide its use. The goal of this brief review was to educate psychiatrists about the basic concepts of nitrous oxide administration and pharmacology. Furthermore, common misconceptions about nitrous oxide will be discussed.
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Fluegge K. Letter to the Editor: Exposure to nitrous oxide and intrusive memory formation in psychological trauma. Psychol Med 2018; 48:874-875. [PMID: 28712366 DOI: 10.1017/s003329171700191x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- K Fluegge
- Institute of Health and Environmental Research,Cleveland,OH,USA
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27
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Visser RM, Lau-Zhu A, Henson RN, Holmes EA. Multiple memory systems, multiple time points: how science can inform treatment to control the expression of unwanted emotional memories. Philos Trans R Soc Lond B Biol Sci 2018; 373:20170209. [PMID: 29352036 PMCID: PMC5790835 DOI: 10.1098/rstb.2017.0209] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/04/2017] [Indexed: 01/04/2023] Open
Abstract
Memories that have strong emotions associated with them are particularly resilient to forgetting. This is not necessarily problematic, however some aspects of memory can be. In particular, the involuntary expression of those memories, e.g. intrusive memories after trauma, are core to certain psychological disorders. Since the beginning of this century, research using animal models shows that it is possible to change the underlying memory, for example by interfering with its consolidation or reconsolidation. While the idea of targeting maladaptive memories is promising for the treatment of stress and anxiety disorders, a direct application of the procedures used in non-human animals to humans in clinical settings is not straightforward. In translational research, more attention needs to be paid to specifying what aspect of memory (i) can be modified and (ii) should be modified. This requires a clear conceptualization of what aspect of memory is being targeted, and how different memory expressions may map onto clinical symptoms. Furthermore, memory processes are dynamic, so procedural details concerning timing are crucial when implementing a treatment and when assessing its effectiveness. To target emotional memory in its full complexity, including its malleability, science cannot rely on a single method, species or paradigm. Rather, a constructive dialogue is needed between multiple levels of research, all the way 'from mice to mental health'.This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'.
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Affiliation(s)
- Renée M Visser
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
| | - Alex Lau-Zhu
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Richard N Henson
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
| | - Emily A Holmes
- Medical Research Council Cognition and Brain Sciences Unit, University of Cambridge, 15 Chaucer Road, Cambridge CB2 7EF, UK
- Karolinska Institutet, Division of Psychology, Department of Clinical Neuroscience, Stockholm, Sweden
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Walsh K, Das RK, Kamboj SK. The Subjective Response to Nitrous Oxide is a Potential Pharmaco-Endophenotype for Alcohol Use Disorder: A Preliminary Study with Heavy Drinkers. Int J Neuropsychopharmacol 2016; 20:346-350. [PMID: 27401180 PMCID: PMC5409036 DOI: 10.1093/ijnp/pyw063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/07/2016] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Healthy people with a family history of alcohol problems show a pattern of subjective responses to alcohol that resemble those of affected probands. Studies on ketamine suggest that up-regulation of N-methyl-D-aspartate receptors (NMDARs) underlies these effects, and point to a pharmacologically-responsive endophenotype reflecting enhanced risk for alcohol-use disorders. METHODS Subjective stimulant and sedative effects were assessed before and during nitrous oxide (N2O; 50%) inhalation in heavy drinkers who were otherwise healthy. RESULTS Participants with an ostensible family history of alcohol-use disorders (n = 23) were distinguishable from those without such familial risk (n = 37) by an enhanced stimulation-to-sedation ratio during N2O inhalation. CONCLUSION The pattern of subjective effects of N2O according to familial risk is remarkably similar to that previously seen with ketamine, supporting the idea of a common, NMDAR-mediated mechanism of action. N2O may prove to be a safe and accessible alternative to ketamine for probing heritable NMDAR dysregulation in neuropsychiatric disorders.
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Affiliation(s)
- Katie Walsh
- Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, University College London, Gower Street, London
| | - Ravi K Das
- Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, University College London, Gower Street, London
| | - Sunjeev K Kamboj
- Clinical Psychopharmacology Unit, Research Department of Clinical, Educational and Health Psychology, University College London, Gower Street, London
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