The PCP Psychosis: Prolonged Intoxication or Drug-Precipitated Functional Illness?

Erard, Robert E.; Luisada, Paul V.; Peele, Roger

doi:10.1080/02791072.1980.10471432

Cited by 52 publications

(14 citation statements)

References 19 publications

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“…Individuals with schizophrenia show greater sensitivity than normal individuals to psychotomimetic effects of both PCP 63 and ketamine, [64][65][66] suggesting that these compounds affect a system that is already vulnerable in schizophrenia. Even among nonschizophrenic individuals, reduced NMDAR activity, as reflected in measures such as decreased amplitude of mismatch negativity (MMN), predicts sensitivity to psychosis during ketamine challenge.…”

Section: Cognitive and Neurochemical Effects Of Nmda Blockadementioning

confidence: 99%

“…Studies with such models have shown persistent alterations in cognitive performance and dopamine turnover in frontal lobe. 84,85 A caution regarding such models, however, is that psychotomimetic effects of PCP or ketamine rarely persist for more than 1-2 weeks following discontinuation of abuse, 63 even though repeated abuse may lead to persistent neurocognitive deficits. 86,87 High doses of NMDAR antagonists, including PCP, ketamine and MK-801, lead to well-described neurotoxic effects, particularly in frontal and cingulate brain regions.…”

Section: Animal Modelsmentioning

confidence: 99%

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Glutamate as a therapeutic target in psychiatric disorders

2004

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Glutamate is the primary excitatory neurotransmitter in the mammalian brain. Glutamatergic neurotransmission may be modulated at multiple levels, only a minority of which are currently being exploited for pharmaceutical development. Ionotropic receptors for glutamate are divided into N-methyl-D-aspartate receptor (NMDAR) and AMPA receptor subtypes. NMDAR have been implicated in the pathophysiology of schizophrenia. The glycine modulatory site of the NMDAR is currently a favored therapeutic target, with several modulatory agents currently undergoing clinical development. Of these, the full agonists glycine and D-serine have both shown to induce significant, large effect size reductions in persistent negative and cognitive symptoms when added to traditional or newer atypical antipsychotics in double-blind, placebo-controlled clinical studies. Glycine (GLYT1) and small neutral amino-acid (SNAT) transporters, which regulate glycine levels, represent additional targets for drug development, and may represent a site of action of clozapine. Brain transporters for D-serine have recently been described. Metabotropic glutamate receptors are positively (Group I) or negatively (Groups II and III) coupled to glutamatergic neurotransmission. Metabotropic modulators are currently under preclinical development for neuropsychiatric conditions, including schizophrenia, depression and anxiety disorders. Other conditions for which glutamate modulators may prove effective include stroke, epilepsy, Alzheimer disease and PTSD. Glutamate is the primary excitatory neurotransmitter in the mammalian brain. Approximately 60% of neurons in the brain, including all cortical pyramidal neurons and thalamic relay neurons, utilize glutamate as their primary neurotransmitter. 1 As a result, virtually all thalamocortical, corticocortical and corticofugal neurotransmission in the brain is mediated by glutamate. Glutamate is released from presynaptic terminals in response to neuronal depolarization, and is recycled by excitatory amino acid (EAA) transporters located on both neurons and glia. 2 Within glia, glutamate is converted to glutamine and released into extracellular fluid from which it is reabsorbed into presynaptic terminals and converted back to glutamate via action of neuronal glutaminase. Up to 2/3 of brain energy metabolism is related to reuptake and recycling of glutamate. 3 As such, functional imaging modalities, such as PET and fMRI, indexing activity primarily of brain glutamatergic systems. 4 The exchange of glutamine from glia to neurons is accomplished by coordinated actions of two transport systems, systems N and A, both of which are members of sodium-dependent neutral amino acid (SNAT) family of transporters. 5 These transport systems also transport precursors for cysteine and glycine, which are precursors to glutathione synthesis. 6 As these transporters are electrogenic, glutamate transporters may also participate in cellular signaling. 7 As with glutamate and GABA transporters, these recycling systems may constitute interesti...

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Section: Cognitive and Neurochemical Effects Of Nmda Blockadementioning

confidence: 99%

Section: Animal Modelsmentioning

confidence: 99%

Glutamate as a therapeutic target in psychiatric disorders

2004

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“…Early investigators characterized a PCP-induced clinical syndrome of schizophrenia-like symptoms, including hallucinations, delusions, idiosyncratic and illogical thinking, poverty of speech and thought, agitation, disturbances of emotion, affect, withdrawal, decreased motivation, and dissociation (Johnstone et al 1959;Luby et al 1959;Rosenbaum et al 1959;Luby et al 1962;Corssen and Domino 1966;Bakker and Amini 1961;Davies and Beech 1960;Domino and Luby 1981). This PCP-induced syndrome can be indistinguishable from acute presentations of schizophrenia (Yesavage and Freeman 1978;Erard et al 1980). Ketamine, a PCP analog still used in human anesthesia, has been reported to cause reactions similar to but not as severe as those caused by PCP, including brief, reversible "positive" and "negative" schizophrenia-like symptoms (Krystal et al 1994;Malhotra et al 1996).…”

mentioning

confidence: 99%

Ketamine-Induced NMDA Receptor Hypofunction as a Model of Memory Impairment and Psychosis

Newcomer

Farber

Jevtović-Todorović

et al. 1999

Neuropsychopharmacology

546

350

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Considerable research interest has recently been focused on the role of glutamate and related neural circuitry in the neurobiology of schizophrenia. The results of these investigations have emphasized hypofunction of glutamatergic neurons and/or the N-methyl-D-aspartate (NMDA) glutamate receptor (Tsai et al. 1995;Kim et al. 1980aKim et al. , 1980bSherman et al. 1991;Deutsch et al. 1989;Javitt and Zukin 1991;Olney 1988a;Olney 1988b;Olney and Farber 1995). An important element of several of these theoretical positions is that NMDA receptor hypofunction (NRH) produced by any mechanism can be psychotogenic. This has renewed interest in the clinical effects of NMDA glutamate receptor antagonists.Ketamine and phencyclidine (PCP) are non-competitive NMDA glutamate receptor antagonists (Zukin and Zukin 1979;Vincent et al. 1979;Lodge and Anis 1982;Lodge et al. 1987) which can produce a transient state of NRH in the brain. Early investigators characterized a PCP-induced clinical syndrome of schizophrenia-like Received March 18, 1998; revised June 19, 1998; accepted June 29, 1998. N EUROPSYCHOPHARMACOLOGY 1999 -VOL . 20 , NO . 2 NMDA Receptor Hypofunction Induced Memory Decrease 107 symptoms, including hallucinations, delusions, idiosyncratic and illogical thinking, poverty of speech and thought, agitation, disturbances of emotion, affect, withdrawal, decreased motivation, and dissociation (Johnstone et al. 1959;Luby et al. 1959;Rosenbaum et al. 1959;Luby et al. 1962;Corssen and Domino 1966;Bakker and Amini 1961;Davies and Beech 1960;Domino and Luby 1981). This PCP-induced syndrome can be indistinguishable from acute presentations of schizophrenia (Yesavage and Freeman 1978;Erard et al. 1980). Ketamine, a PCP analog still used in human anesthesia, has been reported to cause reactions similar to but not as severe as those caused by PCP, including brief, reversible "positive" and "negative" schizophrenia-like symptoms (Krystal et al. 1994;Malhotra et al. 1996). Both PCP and ketamine can exacerbate psychosis in schizophrenia Luby et al. 1962;Lahti et al. 1995a;Lahti et al. 1995b;Malhotra et al. 1997).Declarative, explicit or secondary memory and learning deficits in patients with schizophrenia occur early in the course of the illness and are quantitatively large compared with deficits in other differentiated elements of cognitive performance, showing stability "on" versus "off" antipsychotic medication and over repeated testing (Gruzelier et al. 1988;Saykin et al. 1991Saykin et al. , 1994Cannon et al. 1994). Clinical and preclinical investigations suggest the hypothesis that changes in NMDA glutamate receptor activity in patients with schizophrenia may be causally related to memory impairments found in this disorder. Relevant to this hypothesis, the activation of post-synaptic NMDA receptors is important for the induction of the activity-dependent synaptic modification called long-term potentiation (LTP) (Bliss and Collingridge 1993;Collingridge and Bliss 1995), and hippocampal LTP has been postulated to underlie cert...

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“…80 One of the most interesting effects of PCP in humans is that PCP-intoxicated patients can not be distinguished from schizophrenic patients on the basis of presenting symptoms alone. [81][82][83] In normal volunteers subanesthetic doses of PCP can produce an acute psychotic state for several hours, and overall behavioral symptoms resemble acute schizophrenic decompensation. 79 In animals, PCP causes a variety of behavioral changes which include changes in locomotor activity, stereotypes, ataxia, lateral head weaving, back pedaling and turning.…”

Section: Schizophrenia and Circling Behavior: From Animals To Manmentioning

confidence: 99%

Neurobiological basis of relapse prediction in stimulant-induced psychosis and schizophrenia: the role of sensitization

et al. 1999

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A number of consistent clinical observations provide direction for the hypothesis that pathological sensitization of neuronal systems may be an important factor for relapse or the onset of stimulant-induced psychosis (eg, methamphetamine or amphetamine psychosis, cocaine psychosis and phencyclidine psychosis) and schizophrenia. First, psychotic symptoms can be produced in normal subjects by stimulants. Secondly, a large portion of schizophrenic patients exhibit exacerbation of psychotic symptoms in response to stimulants at doses which would not be psychotogenic in normal subjects. Lastly, the ability of stress to precipitate the onset and relapse of schizophrenia is well documented. In this regard, acute responses to stimulants provide useful information for relapse prediction of schizophrenia and substance abuse. This paper addresses the nature and role of pathological sensitization in relapse of stimulant-and phencyclidine-induced psychosis and schizophrenia, and its relation to pathophysiology of schizophrenia.

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The PCP Psychosis: Prolonged Intoxication or Drug-Precipitated Functional Illness?

Cited by 52 publications

References 19 publications

Glutamate as a therapeutic target in psychiatric disorders

Glutamate as a therapeutic target in psychiatric disorders

Ketamine-Induced NMDA Receptor Hypofunction as a Model of Memory Impairment and Psychosis

Neurobiological basis of relapse prediction in stimulant-induced psychosis and schizophrenia: the role of sensitization

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