BACKGROUND Recent brain imaging studies have indicated that schizophrenia is associated with increased amphetamine-induced dopamine release in the striatum. It has long been hypothesized that dysregulation of subcortical dopamine systems in schizophrenia might result from a failure of the prefrontal cortex (PFC) to adequately control subcortical dopaminergic function. The activity of midbrain...
N-Methyl-D-aspartate (NMDA) receptor antagonists, including phencyclidine (PCP) and dizocilpine (MK801), cause schizophrenialike psychosis in humans, and produce vacuolated neurons in the cingulate and retrosplenial cortices of the rat brain. Since psychotically depressed patients and schizophrenic depressed patients may require treatment with selective serotonin reuptake inhibitors (SSRIs), it...
BACKGROUND The demands of the Wisconsin Card Sorting Test (WCST) change with experience. This report contains two studies designed to examine N-methyl-D-aspartate (NMDA) receptor contributions to the executive components of WCST performance. These aspects of WCST performance figure more prominently in the initial completion of this task than in subsequent task repetitions in healthy...
Sleep disturbances are one of the hallmarks of posttraumatic stress disorder (PTSD); however, sleep laboratory studies have provided inconsistent evidence of the existence of objective sleep disturbances in PTSD patients. Reports that awaking thresholds from sleep in war-related PTSD patients were significantly elevated compared to normals are discordant with complaints of insomnia. The present...
Prepulse inhibition (PPI) of the acoustic startle reflex, a measure of sensory gating, is reduced in schizophrenic patients. Dopamine agonists and NMDA receptor antagonists such as phencyclidine (PCP) can disrupt PPI in animals, consistent with both the dopamine and glutamate hypotheses of schizophrenia. In this study, we sought to further characterize the effects of the NMDA antagonist...
Tolerance of the behavioral effects of the short-acting, endogenous hallucinogen, N,N-dimethyltryptamine (DMT) is seen inconsistently in animals, and has not been produced in humans. The nature and time course of responses to repetitive, closely spaced administrations of an hallucinogenic dose of DMT were characterized. Thirteen experienced hallucinogen users received intravenous 0.3 mg/kg DMT...
The psychological, neuropsychological, and neurometabolic effects of the hallucinogenic agent mescaline were investigated in 12 normal men who were volunteers. Mescaline produced an acute psychotic state 3 1/2-4 hr after drug intake, as measured by the Brief Psychiatric Rating Scale (BPRS) and Paranoid Depression Scale (PDS). The Assessment of Altered States of Consciousness (APZ) questionnaire...
( +_ )3,4-Methylenedioxymethamphetamine (MDMA) is a synthetic amphetamine analogue used recreationally by humans in the United States (Pcroutka 1987) and Western Europe (Anon 1992), and is thought by some to have potential utility as a psychotherapoutic adjunct (Grinspoon and Bakalar 1986). It is generally believed that MDMA acts via central monoamines, primariJy by inducing transmitter release...
Depersonalization disorder is classified in DSM-III-R (APA 1987) as a dissociative disorder characterized by altered perception or experience of the self. To date, there are no known reports of the neurobiological features of this disorder. We report clinical and biological correlates in a patient with depersonalization disorder previously unresponsive to a variety of anticonvulsant, monoamine...
Although the psychotomimetic indolealkylamines N,N-dimethyltryptamine, 5-methoxy-N,N-dimethyltryptamine, and 5-hydroxy-N,N-dimethyltryptamine have been unequivocally identified in human body fluids, evidence relating their concentration to the presence of psychotic illness in humans remains controversial. A series of studies on the metabolism of the compounds in the rat have highlighted the...
We have assayed several phenylalkylamine and indolealkylamine hallucinogens, as well as structurally similar nonhallucinogens, for their effect on human platelet shape change, a physiological model for the central serotonergic 5-HT2 receptor. The hallucinogenic drugs lysergic acid diethylamide (LSD-25), N,N-dimethyltryptamine (N,N-DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeODMT),...
Studying the meaning of dreams is difficult and subject to many methodological pitfalls. One of these is vagueness and inconsistancy in defining dream content variables that are used as independent measures. This study evaluated the effect, upon accurate definition of the independent variable, of repeating the dream report and of using associative content as dream material. The importance of...
Recent studies have shown that dreaming is not limited to rapid eye movement (REM) sleep, but can be found to varying degrees in any stage of sleep. This study attempted to quantify the EEG correlations of dreaming during Stage 2 sleep. Six normal volunteers were studied for 24 nights in the sleep laboratory. Electroencephalogram (EEG) recording prior to awakening from Stage 2 sleep and from...