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Biomedical subjects

Torsten Passie

Publications and source records attributed to Torsten Passie.

10 recordsLinked to original sources
PubMed2005

Effects of different subanesthetic doses of (S)-ketamine on neuropsychology, psychopathology, and state of consciousness in man.

This is the first neuropsychological study using the S-enantiomer of the noncompetitive N-methyl-D-aspartate antagonist ketamine. In 2 randomized placebo-controlled trials we studied effects of two different doses of (S)-ketamine (low dose/high dose) on neuropsychological functions and psychopathology in 12 healthy male volunteers. Impairment was measured via standardized neuropsychological tests. Results indicate that both subanaesthetic doses produce only nonsignificant impairment in most of the tasks. Tasks involving divided and sustained attention as well as scores for objective and subjective psychopathology show significant impairment in a dose-dependent manner. Implications of these findings for the neuropsychology of attention and schizophrenia are discussed.

Adult↗
PubMed2005

Ecstasy (MDMA) mimics the post-orgasmic state: impairment of sexual drive and function during acute MDMA-effects may be due to increased prolactin secretion.

Methylenedioxymethamphetamine (MDMA or "Ecstasy") is a major stimulant drug of abuse worldwide. MDMA produces euphoria, enhances interpersonal communication and feelings of closeness with others. In contrast to the induced emotions of affection and sensual enhancement, clinical studies show that it impairs sexual drive and functioning. In drug-free humans, sexual stimulation with orgasm induces a pronounced secretion of prolactin, which may mediate the post-orgasmic state. The phenomenological features of the psychological state induced by MDMA show some similarities with features of the post-orgasmic state. In addition, MDMA also induces a prominent increase of prolactin plasma levels with a similar time kinetic compared to the post-orgasmic prolactin increase. Here, we present the hypothesis that the impairment of sexual parameters after MDMA may be mediated by increased prolactin.

N-Methyl-3,4-methylenedioxyamphetamine↗
PubMed2003

On the function of groaning and hyperventilation during sexual intercourse: intensification of sexual experience by altering brain metabolism through hypocapnia.

Sexual arousal is accompanied by some typical physiological reaction patterns. Another typical feature of sexual intercourse is involuntary sound production implying in its more intense forms acceleration of breathing (hyperventilation). Up to now no study examined spCO2 during intense sexual intercourse, but there is evidence that some degree of hyperventilation with its physiological consequences may often be induced during sexual intercourse. This article discusses implications of hyperventilation during sexual intercourse for alterations of consciousness and subjective experience in the light of recent studies of brain metabolic changes during states of hyperventilation. Groaning and hyperventilation are interpreted in this context as a psychophysiological mechanism to deepen states of sexual trance.

Brain↗
PubMed2003

Effects of acute alcohol withdrawal on memory performance in alcohol-dependent patients: a pilot study.

Studies on the neuropsychological performance in detoxified alcoholic patients often begin by acknowledging that there is a cognitive impairment to be found. Only little attention has been paid to date to the question as to how acute alcohol withdrawal might affect cognitive functions. Twenty-nine alcohol-dependent inpatients, nine in moderate alcohol withdrawal, treated with carbamazepine (group 1), 10 in mild alcohol withdrawal without pharmacological treatment (group 2), 10 in mild alcohol withdrawal with carbamazepine treatment (group 3) and 31 healthy subjects as controls (group 4) underwent repeated investigations using memory tests. The tests were performed on the first, third, seventh and fourteenth days of withdrawal. Immediate free recall of a word-list was impaired in the three patient groups in comparison with the control group on the 1st day. Thereafter no significant differences could be revealed between patients and controls. In a word-list recognition test the memory functions were not impaired in group 1 and group 2 in comparison with the control subjects. However, patients in group 3 showed impairment in this recognition test in comparison with the healthy subjects on the first and third days. The present study suggests that acute alcohol withdrawal impairs memory functions, especially free recall. This should be considered in treatment interventions in the early days of withdrawal.

Adult↗
PubMed2003

Effects of different subanaesthetic doses of (S)-ketamine on psychopathology and binocular depth inversion in man.

The role of the N-methyl-D-aspartate (NMDA) neurotransmitter system in relation to psychoses is not completely understood, but represent a challenge in neurobiological research. The psychotic states induced by NMDA antagonists such as phencyclidine and ketamine have been described as being most similar to schizophrenia and the NMDA system has been implicated in the pathogenesis of schizophrenia. Binocular depth inversion, an illusion of visual perception, has been shown to be impaired in psychotic and psychotomimetic states in healthy and schizophrenic subjects. In this study, pictures of natural and artificial objects were presented stereoscopically to 12 healthy male volunteers and depth perception assessed using an operationalized method. The effects of the psychotomimetic S-enantiomer of the anaesthetic ketamine in two different subanaesthetic doses were compared with those of a placebo. In spite of dose dependence and grave subjective and significant objective psychopathology, no significant impairment of binocular depth perception was found with (S)-ketamine. Implications related to memory function, perceptogenesis and 'bottom-up' processing in ketamine model psychosis and schizophrenia are discussed.

Adult↗
PubMed2002

The pharmacology of psilocybin.

Psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine) is the major psychoactive alkaloid of some species of mushrooms distributed worldwide. These mushrooms represent a growing problem regarding hallucinogenic drug abuse. Despite its experimental medical use in the 1960s, only very few pharmacological data about psilocybin were known until recently. Because of its still growing capacity for abuse and the widely dispersed data this review presents all the available pharmacological data about psilocybin.

Agaricales↗
PubMed2002

Acupuncture in the treatment of alcohol withdrawal symptoms: a randomized, placebo-controlled inpatient study.

Thirty-four alcoholics were treated with acupuncture to the ear and the body in a randomized single-blind placebo-controlled design over 14 days. Orthodox points and placebo needles to orthodox points were used daily for a total of 10 treatments starting on the first day of admission as add-on therapy to standard medication with carbamazepine. The primary outcome was the Clinical Institute Withdrawal Assessment (CIWA-Ar-scale) assessed on days 1-6, 9 and 14. No initial differences were found regarding sociodemographic data, drinking history and alcohol-related data, indicating successful randomization. Longitudinal analysis of the Clinical Institute Withdrawal Assessment (CIWA-Ar-scale) data showed that patients assigned to acupuncture had a general tendency towards better outcome results and significantly fewer withdrawal symptoms on day 14 (Wilcoxon-W=177.500, Z=-2.009, p = 0.045). No significant differences were found in the Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI X1 and X2) and Eigenschaftswoerterliste (EWL S60). We conclude that acupuncture as an adjunctive treatment to carbamazepine medication shows promise for the treatment of alcohol withdrawal symptoms. Further investigation of this treatment modality appears to be warranted.

Acupuncture Therapy↗
PubMedDate not supplied

Abnormality in the self-monitoring mechanism in patients with fibromyalgia and somatoform pain disorder.

BACKGROUND: Auditory hallucinations and passivity experiences are associated with an abnormality in the self-monitoring mechanism that normally allows us to distinguish self-produced from externally produced sensations. It is unclear if chronic central pain disorders such as fibromyalgia and somatoform pain disorders also involve a defect of the self-monitoring mechanism. METHODS: Responses to tactile stimulation were assessed in four groups of subjects (N = 40): patients with fibromyalgia, patients with somatoform pain disorder, patients with schizophrenia with auditory hallucinations and/or passivity experiences, and normal control subjects. The subjects were asked to rate the perception of a tactile sensation on their left and right hands. The tactile stimulation was either self-produced by movement of the subject's right or left hand or externally produced by the experimenter. RESULTS: Normal control subjects experienced self-produced stimuli as less intense than identical, externally produced tactile stimuli. In contrast, patients with fibromyalgia, patients with somatoform pain disorder, and patients with schizophrenia with auditory hallucinations and/or passivity experiences gave the same perceptual ratings for tactile stimuli produced by themselves as those produced by the experimenter (intergroup difference, p = .043; 95% confidence interval [CI], 0.16-0.68). Post hoc tests revealed that this significance was mainly caused by the fibromyalgia (p = .046; 95% CI, -1.66-0.13) and the somatoform pain disorder group (p = .033; 95% CI, -1.71-0.06). CONCLUSIONS: We conclude that central pain disorders such as fibromyalgia and somatoform pain disorders interfere with the correct functioning of the self-monitoring mechanism that normally allows us to distinguish self-produced from externally produced tactile stimuli.

Acute Disease↗