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Le TT, Cordero IP, Jawad MY, Swainson J, Di Vincenzo JD, Jaberi S, Phan L, Lui LMW, Ho R, Rosenblat JD, McIntyre RS. The abuse liability of ketamine: A scoping review of preclinical and clinical studies. J Psychiatr Res 2022; 151:476-496. [PMID: 35623124 DOI: 10.1016/j.jpsychires.2022.04.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/17/2022] [Accepted: 04/25/2022] [Indexed: 12/22/2022]
Abstract
While ketamine has been used clinically over the past decades, it has only been recently shown to be a promising therapy for treatment-resistant depression (TRD). However, ketamine and related dissociative agents may also be misused recreationally, creating significant concerns for abuse liability when prescribed for depression. Although the abuse potential of ketamine is widely recognized, there is limited evidence on the differential abuse liability of ketamine enantiomers, (S)-ketamine and (R)-ketamine. The current scoping review aims to summarize the extant literature on the abuse liability of (R,S)-ketamine and the enantiomers. A systematic search was conducted on the Embase, Medline, and APA PsycInfo databases from 1947 to July 29, 2021. Clinical and preclinical studies that assessed the abuse potential of (R,S)-ketamine, (S)-ketamine, and (R)-ketamine were screened and assessed for eligibility by two independent reviewers. A total of 65 eligible studies were identified; 55 were preclinical studies and 10 were clinical studies. Only 4 preclinical studies evaluated the abuse liability of ketamine enantiomers. Available preclinical evidence suggests that (R,S)-ketamine and (S)-ketamine have greater risk for abuse compared to (R)-ketamine. (R)-ketamine, at the antidepressant-relevant doses in rodents, appears to be safe with minimal liability for abuse. Although the abuse potential of (R,S)-ketamine is well-established in animals, limited clinical studies indicate that single or repeated ketamine administrations in professionally controlled settings did not result in misuse, dependence, diversion and/or gateway activity in patients with TRD. However, most clinical studies were retrospective and did not systematically evaluate the abuse liability of ketamine via validated psychological scales/questionnaires. Future randomized controlled trials are warranted to ascertain the abuse liability of racemic, (S)- and (R)-ketamine in TRD population, especially among patients with comorbid substance use disorders.
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Affiliation(s)
- Tuyen T Le
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Isabel Pazos Cordero
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada; Department of Human Biology, University of Toronto, Toronto, ON, Canada
| | - Muhammad Youshay Jawad
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada
| | | | - Joshua D Di Vincenzo
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Saja Jaberi
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada
| | - Lee Phan
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada
| | - Leanna M W Lui
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada; Institute of Medical Science, University of Toronto, ON, Canada
| | - Roger Ho
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; Institute for Health Innovation and Technology (iHealthtech), National University of Singapore, Singapore, Singapore
| | - Joshua D Rosenblat
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada; Department of Psychiatry, University of Alberta, Edmonton, Canada; Institute of Medical Science, University of Toronto, ON, Canada; Canadian Rapid Treatment Center of Excellence, Mississauga, ON, Canada
| | - Roger S McIntyre
- Mood Disorders Psychopharmacology Unit, Poul Hansen Family Centre for Depression, University Health Network, Toronto, ON, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada; Canadian Rapid Treatment Center of Excellence, Mississauga, ON, Canada; Brain and Cognition Discovery Foundation, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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Schlag AK, Aday J, Salam I, Neill JC, Nutt DJ. Adverse effects of psychedelics: From anecdotes and misinformation to systematic science. J Psychopharmacol 2022; 36:258-272. [PMID: 35107059 PMCID: PMC8905125 DOI: 10.1177/02698811211069100] [Citation(s) in RCA: 68] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Despite an increasing body of research highlighting their efficacy to treat a broad range of medical conditions, psychedelic drugs remain a controversial issue among the public and politicians, tainted by previous stigmatisation and perceptions of risk and danger. OBJECTIVE This narrative review examines the evidence for potential harms of the classic psychedelics by separating anecdotes and misinformation from systematic research. METHODS Taking a high-level perspective, we address both psychological and psychiatric risks, such as abuse liability and potential for dependence, as well as medical harms, including toxicity and overdose. We explore the evidence base for these adverse effects to elucidate which of these harms are based largely on anecdotes versus those that stand up to current scientific scrutiny. RESULTS Our review shows that medical risks are often minimal, and that many - albeit not all - of the persistent negative perceptions of psychological risks are unsupported by the currently available scientific evidence, with the majority of reported adverse effects not being observed in a regulated and/or medical context. CONCLUSIONS This highlights the importance for clinicians and therapists to keep to the highest safety and ethical standards. It is imperative not to be overzealous and to ensure balanced media reporting to avoid future controversies, so that much needed research can continue.
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Affiliation(s)
- Anne K Schlag
- Drug Science, London, UK,Department of Brain Sciences, Imperial College London, London, UK,Department of Geography, King’s College London, London, UK
| | - Jacob Aday
- Drug Science, London, UK,Department of Psychology, Central Michigan University, Mount Pleasant, MI, USA,Department of Psychiatry and Behavioral Sciences, University of California, Davis, Sacramento, CA, USA
| | | | - Jo C Neill
- Drug Science, London, UK,Division of Pharmacy and Optometry, School of Health Sciences, The University of Manchester, Manchester, UK
| | - David J Nutt
- Drug Science, London, UK,Department of Brain Sciences, Imperial College London, London, UK,David J Nutt, Department of Brain Sciences, Imperial College London, Burlington Danes Building, The Hammersmith Hospital, London W12 0NN, UK.
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Volgin AD, Yakovlev OA, Demin KA, Alekseeva PA, Kyzar EJ, Collins C, Nichols DE, Kalueff AV. Understanding Central Nervous System Effects of Deliriant Hallucinogenic Drugs through Experimental Animal Models. ACS Chem Neurosci 2019; 10:143-154. [PMID: 30252437 DOI: 10.1021/acschemneuro.8b00433] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hallucinogenic drugs potently alter human behavior and have a millennia-long history of use for medicinal and religious purposes. Interest is rapidly growing in their potential as CNS modulators and therapeutic agents for brain conditions. Antimuscarinic cholinergic drugs, such as atropine and scopolamine, induce characteristic hyperactivity and dream-like hallucinations and form a separate group of hallucinogens known as "deliriants". Although atropine and scopolamine are relatively well-studied drugs in cholinergic physiology, deliriants represent the least-studied class of hallucinogens in terms of their behavioral and neurological phenotypes. As such, novel approaches and new model organisms are needed to investigate the CNS effects of these compounds. Here, we comprehensively evaluate the preclinical effects of deliriant hallucinogens in various animal models, their mechanisms of action, and potential interplay with other signaling pathways. We also parallel experimental and clinical findings on deliriant agents and outline future directions of translational research in this field.
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Affiliation(s)
- Andrey D. Volgin
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg 199034, Russia
- Almazov National Medical Research Centre, St. Petersburg 197341, Russia
- Military Medical Academy, St. Petersburg 194044, Russia
| | - Oleg A. Yakovlev
- Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg 199034, Russia
- Almazov National Medical Research Centre, St. Petersburg 197341, Russia
- Military Medical Academy, St. Petersburg 194044, Russia
| | | | | | - Evan J. Kyzar
- College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, United States
- The International Zebrafish Neuroscience Research Consortium (ZNRC), New Orleans, Louisiana 70458, United States
| | - Christopher Collins
- The International Zebrafish Neuroscience Research Consortium (ZNRC), New Orleans, Louisiana 70458, United States
| | - David E. Nichols
- Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Allan V. Kalueff
- School of Pharmacy, Southwest University, Chongqing 400716, China
- Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk 630117, Russiai
- Ural Federal University, Ekaterinburg 620075, Russia
- ZENEREI Research Center, Slidell, Louisiana 70458, United States
- Laboratory of Biological Psychiatry, Institute of Translational Biomedicine, St. Petersburg State University, St. Petersburg 199034, Russia
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Ingram R, Kang H, Lightman S, Jane DE, Bortolotto ZA, Collingridge GL, Lodge D, Volianskis A. Some distorted thoughts about ketamine as a psychedelic and a novel hypothesis based on NMDA receptor-mediated synaptic plasticity. Neuropharmacology 2018; 142:30-40. [PMID: 29885421 DOI: 10.1016/j.neuropharm.2018.06.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 05/27/2018] [Accepted: 06/05/2018] [Indexed: 12/12/2022]
Abstract
Ketamine, a channel blocking NMDA receptor antagonist, is used off-label for its psychedelic effects, which may arise from a combination of several inter-related actions. Firstly, reductions of the contribution of NMDA receptors to afferent information from external and internal sensory inputs may distort sensations and their processing in higher brain centres. Secondly, reductions of NMDA receptor-mediated excitation of GABAergic interneurons can result in glutamatergic overactivity. Thirdly, limbic cortical disinhibition may indirectly enhance dopaminergic and serotonergic activity. Fourthly, inhibition of NMDA receptor mediated synaptic plasticity, such as short-term potentiation (STP) and long-term potentiation (LTP), could lead to distorted memories. Here, for the first time, we compared quantitatively the effects of ketamine on STP and LTP. We report that ketamine inhibits STP in a double sigmoidal fashion with low (40 nM) and high (5.6 μM) IC50 values. In contrast, ketamine inhibits LTP in a single sigmoidal manner (IC50 value ∼ 15 μM). A GluN2D-subunit preferring NMDA receptor antagonist, UBP145, has a similar pharmacological profile. We propose that the psychedelic effects of ketamine may involve the inhibition of STP and, potentially, associated forms of working memory. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.
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Affiliation(s)
- Rachael Ingram
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Heather Kang
- School of Clinical Sciences, University of Bristol, Bristol, UK; Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK; Dept Physiology, University of Toronto and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | | | - David E Jane
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Zuner A Bortolotto
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Graham L Collingridge
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK; Dept Physiology, University of Toronto and Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - David Lodge
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Arturas Volianskis
- Centre for Neuroscience and Trauma, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UK; School of Clinical Sciences, University of Bristol, Bristol, UK.
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Sellers EM, Romach MK, Leiderman DB. Studies with psychedelic drugs in human volunteers. Neuropharmacology 2017; 142:116-134. [PMID: 29162429 DOI: 10.1016/j.neuropharm.2017.11.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/31/2017] [Accepted: 11/17/2017] [Indexed: 12/20/2022]
Abstract
Scientific curiosity and fascination have played a key role in human research with psychedelics along with the hope that perceptual alterations and heightened insight could benefit well-being and play a role in the treatment of various neuropsychiatric disorders. These motivations need to be tempered by a realistic assessment of the hurdles to be cleared for therapeutic use. Development of a psychedelic drug for treatment of a serious psychiatric disorder presents substantial although not insurmountable challenges. While the varied psychedelic agents described in this chapter share some properties, they have a range of pharmacologic effects that are reflected in the gradation in intensity of hallucinogenic effects from the classical agents to DMT, MDMA, ketamine, dextromethorphan and new drugs with activity in the serotonergic system. The common link seems to be serotonergic effects modulated by NMDA and other neurotransmitter effects. The range of hallucinogens suggest that they are distinct pharmacologic agents and will not be equally safe or effective in therapeutic targets. Newly synthesized specific and selective agents modeled on the legacy agents may be worth considering. Defining therapeutic targets that represent unmet medical need, addressing market and commercial issues, and finding treatment settings to safely test and use such drugs make the human testing of psychedelics not only interesting but also very challenging. This article is part of the Special Issue entitled 'Psychedelics: New Doors, Altered Perceptions'.
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Affiliation(s)
- Edward M Sellers
- Departments of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada; Medicine, University of Toronto, Toronto, ON, Canada; Psychiatry, University of Toronto, Toronto, ON, Canada; Surgery, University of Toronto, Toronto, ON, Canada; DL Global Partners Inc, Toronto, ON, Canada.
| | - Myroslava K Romach
- Psychiatry, University of Toronto, Toronto, ON, Canada; Surgery, University of Toronto, Toronto, ON, Canada; DL Global Partners Inc, Toronto, ON, Canada
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Hallucinogenic Agents. Clin Toxicol (Phila) 2010. [DOI: 10.3109/9781420092264-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Winter JC. Hallucinogens as discriminative stimuli in animals: LSD, phenethylamines, and tryptamines. Psychopharmacology (Berl) 2009; 203:251-63. [PMID: 18979087 DOI: 10.1007/s00213-008-1356-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/24/2008] [Indexed: 12/24/2022]
Abstract
BACKGROUND Although man's first encounters with hallucinogens predate written history, it was not until the rise of the sister disciplines of organic chemistry and pharmacology in the nineteenth century that scientific studies became possible. Mescaline was the first to be isolated and its chemical structure determined. Since then, additional drugs have been recovered from their natural sources and synthetic chemists have contributed many more. Given their profound effects upon human behavior and the need for verbal communication to access many of these effects, some see humans as ideal subjects for study of hallucinogens. However, if we are to determine the mechanisms of action of these agents, establish hypotheses testable in human subjects, and explore the mechanistic links between hallucinogens and such apparently disparate topics as idiopathic psychosis, transcendental states, drug abuse, stress disorders, and cognitive dysfunction, studies in animals are essential. Stimulus control by hallucinogens has provided an intuitively attractive approach to the study of these agents in nonverbal species. OBJECTIVE The intent of this review is to provide a brief account of events from the time of the first demonstration of hallucinogen-induced stimulus control to the present. In general, the review is limited to lysergic acid diethylamide (LSD) and the hallucinogenic derivatives of phenethylamine and tryptamine. RESULTS The pharmacological basis for stimulus control by LSD and hallucinogenic phenethylamines and tryptamines is serotonergic in nature. The 5-HT(2A) receptor appears to be the primary site of action with significant modulation by other serotonergic sites including 5-HT(2C) and 5-HT(1A) receptors. Interactions with other neurotransmitters, especially glutamate and dopamine, are under active investigation. Most studies to date have been conducted in the rat but transgenic mice offer interesting possibilities. CONCLUSIONS Hallucinogen-induced stimulus control provides a unique behavioral tool for the prediction of subjective effects in man and for the elucidation of the pharmacological mechanisms of the action of these agents.
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Affiliation(s)
- J C Winter
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, 102 Farber Hall, Buffalo, NY 14214-3000, USA.
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Martelle JL, Nader MA. A within-subject assessment of the discriminative stimulus and reinforcing effects of self-administered cocaine in rhesus monkeys. Psychopharmacology (Berl) 2009; 203:343-53. [PMID: 18807249 PMCID: PMC2738977 DOI: 10.1007/s00213-008-1322-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 08/30/2008] [Indexed: 11/25/2022]
Abstract
RATIONALE Drug discrimination (DD) and drug self-administration (SA) are frequently used preclinical assays. All preclinical studies with cocaine have examined the discriminative stimulus (S(D)) and reinforcing (S(R)) effects in separate groups of subjects. OBJECTIVE The objective of the study is to train drug-naïve rhesus macaques to discriminate self-administered cocaine from saline and to assess S(D) and S(R) effects using a within-subjects design. MATERIALS AND METHODS Adult male rhesus monkeys (n = 4) were trained to self-administer cocaine (0.1 mg/kg per injection) under a progressive-ratio (PR) reinforcement schedule. Next, they were trained to discriminate self-administered cocaine (0.45 or 0.56 mg/kg) or saline under a fixed-ratio (FR) 50 schedule of food presentation. The final schedule combined DD and SA into a multiple [chained FR 50 SA (cocaine or saline), food-reinforced DD] and PR SA schedule. RESULTS Each subject acquired SA under a PR schedule with significant differences in breakpoint between saline and cocaine evident by session 5. Self-administered cocaine was established as an S(D), such that 80% of responding before delivery of the first reinforcer and 90% of all responding occurred on the injection-appropriate lever. In all monkeys, there was at least one cocaine dose that did not engender cocaine-appropriate responding during DD (i.e., <20% cocaine-appropriate responding) yet functioned as a reinforcer during PR SA, suggesting that cocaine-like S(D) effects are not necessary for cocaine reinforcement. CONCLUSIONS This within-subject model may provide new information related to the behavioral mechanisms of action leading to the high abuse potential of cocaine; such information may lead to novel pharmacological treatment strategies for addiction.
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Affiliation(s)
- Jennifer L. Martelle
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, 546 NRC, Medical Center Boulevard, Winston-Salem, NC 27157-1083, USA, e-mail:
| | - Michael A. Nader
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, 546 NRC, Medical Center Boulevard, Winston-Salem, NC 27157-1083, USA, e-mail:
- Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
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Abstract
PURPOSE OF REVIEW This review highlights the epidemiologic research on club drug use in the past year, with a focus on clinical epidemiology, social epidemiology, new methodological approaches, and alternative explanations for drug use behaviors. RECENT FINDINGS Although 3,4-methylenedioxy-N-methylamphetamine (MDMA) or ecstasy is currently classified as a type of hallucinogen and its withdrawal is not recognized in the Diagnostic and Statistical Manual of Mental Disorders, there is evidence for the association of withdrawal symptoms with MDMA abstinence. Findings from latent class analysis indicate that MDMA users have a significantly higher risk of dependence than lysergic acid diethylamide users. Research on sociodemographic factors associated with club drug use continues to be a main focus worldwide. New epidemiologic research methods have been developed to enable researchers to monitor real-time drug use behaviors and to conduct surveys on sensitive issues in public places. In addition to traditional behavioral models, researchers began to examine the club drug phenomenon in the context of economic environment. SUMMARY Recent findings on MDMA use further question the current drug classification in the diagnostic systems. Despite the continuous growth in the club drug research literature, there is no study on the influence of genetic factors on club drug use. More research in this area is needed.
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Stone A, Storr C, Anthony J. Evidence for a hallucinogen dependence syndrome developing soon after onset of hallucinogen use during adolescence. Int J Methods Psychiatr Res 2006; 15:116-30. [PMID: 17019896 PMCID: PMC6878397 DOI: 10.1002/mpr.188] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This study uses latent class methods and multiple regression to shed light on hypothesized hallucinogen dependence syndromes experienced by young people who have recently initiated hallucinogen use. It explores possible variation in risk. The study sample, identified within public-use data files of the 1999 National Household Survey on Drug Abuse (NHSDA), consists of 1186 recent-onset hallucinogen users, defined as having initiated hallucinogen use within 24 months of assessment (median elapsed time since onset of use -12 to 13 months). The recent-onset users in this sample were age 12 to 21 at the time of assessment and were between the ages of 10 and 21 at the time of their first hallucinogen use. The NHSDA included items to assess seven clinical features often associated with hallucinogen dependence, which were used in latent class modelling. Latent class analysis, in conjunction with prior theory, supports a three-class solution, with 2% of recent-onset users in a class that resembles a hallucinogen dependence syndrome, whereas 88% expressed few or no clinical features of dependence. The remaining 10% may reflect users who are at risk for dependence or in an early stage of dependence. Results from latent class regressions indicate that susceptibility to rapid transition from first hallucinogen use to onset of this hallucinogen dependence syndrome might be influenced by hallucinogenic compounds taken (for example, estimated relative risk, RR = 2.4, 95% CI = 1.6, 7.6 for users of MDMA versus users of LSD). Excess risk of rapid transition did not appear to depend upon age, sex, or race/ethnicity.
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Affiliation(s)
- A.L. Stone
- University of Washington School of Nursing, Department of Psychosocial and Community Health, Seattle, USA
| | - C.L. Storr
- Johns Hopkins University Bloomberg School of Public Health, Department of Mental Health, Baltimore, USA
| | - J.C. Anthony
- Michigan State University College of Human Medicine, Department of Epidemiology, East Lansing, USA
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Morgan CJA, Monaghan L, Curran HV. Beyond the K-hole: a 3-year longitudinal investigation of the cognitive and subjective effects of ketamine in recreational users who have substantially reduced their use of the drug. Addiction 2004; 99:1450-61. [PMID: 15500598 DOI: 10.1111/j.1360-0443.2004.00879.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
RATIONALE Ketamine is a dissociative anaesthetic that is also a drug of abuse. Previous studies have demonstrated persisting episodic and semantic memory impairments in recreational ketamine users 3 days after taking ketamine. However, the degree to which these deficits might be reversible upon reduction or cessation of ketamine use was not known. OBJECTIVE To follow-up a population of ketamine users tested 3 years previously and examine whether impairments observed 3 days after drug use are enduring or reversible. METHODS Eighteen ketamine users and 10 polydrug controls from studies conducted between 3 and 4 years earlier were re-tested on the same battery of cognitive tasks and subjective measures. These tapped episodic, semantic and working memory and executive and attentional functioning. Subjective schizotypal, dissociative, mood and bodily symptoms were also examined and a drug use history recorded. RESULTS The ketamine users had reduced their frequency of use of ketamine by an average of 88.3%. Performance of ketamine users on tasks tapping semantic memory had improved and this improvement was correlated with their reduction in ketamine use. On tasks tapping episodic memory and attentional functioning, ketamine users still showed deficits compared to polydrug controls. Higher levels of schizotypal symptoms and perceptual distortions were exhibited by the ketamine group, although dissociative symptoms were similar to controls. CONCLUSIONS These findings indicate that semantic memory impairments associated with recreational ketamine are reversible upon marked reduction of use; however, impairments to episodic memory and possibly attentional functioning appear long-lasting. In addition, schizotypal symptoms and perceptual distortions may persist after cessation of ketamine use. Ketamine users, or potential users, should be aware of the enduring effects of this drug on aspects of memory and subjective experience.
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Affiliation(s)
- Celia J A Morgan
- Clinical Psychopharmacology Unit, University College London, London, UK.
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Brust JC. Other Agents: Phencyclidine, Marijuana, Hallucinogens, Inhalants, and Anticholinergics. Neurol Clin 1993. [DOI: 10.1016/s0733-8619(18)30138-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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