Dissociation, hypnotizability, coping styles and health locus of control: characteristics of pseudoseizure patients.
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Although literature in this area is relatively sparse, the occurrence of psychogenic non-epileptic seizures (pseudoseizures) has been linked to stress, anxiety and possible dissociative tendencies. An association between dissociation and hypnotic susceptibility has also been proposed and dissociative tendencies have themselves been found to relate to the use of emotion-focused coping strategies. In order to investigate the hypothesis that pseudoseizure patients may exhibit higher levels of dissociation, a more emotion-focused coping style, and greater hypnotic susceptibility than the general population, the questionnaire responses of 20 patients with pseudoseizures were compared with those obtained from a non-clinical control group. As predicted, pseudoseizure patients demonstrated some evidence of higher levels of dissociation and escape-avoidance coping strategies. They also expressed a greater belief in external control over health and higher depression scores, compared to the control group, but the previously reported elevation in hypnotizability scores in the pseudoseizure patients was not found. Possible explanations for this pattern of results are discussed. (+info)
Dissociation in conditioned dopamine release in the nucleus accumbens core and shell in response to cocaine cues and during cocaine-seeking behavior in rats.
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The dopaminergic innervation of the nucleus accumbens is generally agreed to mediate the primary reinforcing and locomotor effects of psychostimulants, but there is less consensus on conditioned dopamine (DA) release during drug-seeking behavior. We investigated the neurochemical correlates of drug-seeking behavior under the control of a drug-associated cue [a light conditioned stimulus (CS+)] and to noncontingent presentations of the CS+ in the core and shell subregions of the nucleus accumbens. Rats self-administered cocaine under a continuous reinforcement schedule in which a response on one of two identical levers led to an intravenous cocaine infusion (0.25 mg/infusion) and a 20 sec light CS+. Response requirements for cocaine and the CS+ were then progressively increased until stable responding was established under a second-order schedule of reinforcement. During microdialysis, rats were presented noncontingently with a set of 10 sec CS+ and neutral tone stimuli (CS-) before and after a 90 min period during which they responded for cocaine under a second-order schedule. Results showed the following: (1) nucleus accumbens DA increased in both the core and shell during intravenous cocaine self-administration; (2) noncontingent presentations of a cocaine-associated CS+ led to increased DA release selectively in the nucleus accumbens core; and (3) extracellular DA levels were unaltered in both core and shell during a protracted period of drug-seeking behavior under the control of the same cocaine-associated cue. These results indicate that the mesolimbic dopamine system is activated after exposure to drug-associated stimuli under specific conditions. (+info)
Is there a dissociative process in sleepwalking and night terrors?
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The enduring and contentious hypothesis that sleepwalking and night terrors are symptomatic of a protective dissociative mechanism is examined. This is mobilised when intolerable impulses, feelings and memories escape, within sleep, the diminished control of mental defence mechanisms. They then erupt but in a limited motoric or affective form with restricted awareness and subsequent amnesia for the event. It has also been suggested that such processes are more likely when the patient has a history of major psychological trauma. In a group of 22 adult patients, referred to a tertiary sleep disorders service with possible sleepwalking/night terrors, diagnosis was confirmed both clinically and polysomnographically, and only six patients had a history of such trauma. More commonly these described sleepwalking/night terrors are associated with vivid dream-like experiences or behaviour related to flight from attack. Two such cases, suggestive of a dissociative process, are described in more detail. The results of this study are presented largely on account of the negative findings. Scores on the dissociation questionnaire (DIS-Q) were normal, although generally higher in the small "trauma" subgroup. These were similar to scores characterising individuals with post-traumatic stress disorder. This "trauma" group also scored particularly highly on the anxiety, phobic, and depression scales of the Crown-Crisp experiential index. In contrast the "no trauma" group scored more specifically highly on the anxiety scale, along with major trends to high depression and hysteria scale scores. Two cases are presented which illustrate exceptional occurrence of later onset of sleepwalking/night terrors with accompanying post-traumatic symptoms during wakefulness. It is concluded that a history of major psychological trauma exists in only a minority of adult patients presenting with sleepwalking/night terror syndrome. In this subgroup trauma appears to dictate the subsequent content of the attacks. However, the symptoms express themselves within the form of the sleepwalking/night terror syndrome rather than as rapid eye movement sleep related nightmares. The main group of subjects with the syndrome and with no history of major psychological trauma show no clinical or DIS-Q evidence of dissociation during wakefulness. The proposition that, within the character structure of this group, the mechanism still operates but exclusively within sleep remains a possibility. (+info)
Psychogenic seizures mimicking juvenile myoclonic epilepsy: case reports.
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We describe two patients with psychogenic seizures of rare semiology. Both patients (a 23-year-old man and a 26-year-old woman) attended the emergency department because status epilepticus with myoclonic seizures had been diagnosed. Seizures were documented with video-electroencephalography. Semiology of seizures were brief myoclonia of both arms resulting in a short elevation of both arms without impairment of consciousness. Ictal EEG registration was without abnormal finding. Psychiatric diagnostic assessment suggested a dissociative disorder and mild depression, respectively. During psychiatric treatment seizures occurred only rarely within a 3-5 months follow-up. One should be aware that juvenile myoclonic epilepsy may be mimicked by psychogenic seizures (+info)
Dissociation between intentional and incidental sequence learning in Huntington's disease.
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The ability to acquire and act upon serial order information is fundamental to almost all forms of adaptive behaviour. There is growing evidence that such knowledge may be acquired through a number of different means, each perhaps with its own neuronal substrate. One major distinction is between serial order information acquired intentionally and leading to explicit conscious knowledge of the sequence structure, and information acquired incidentally through experience. While this latter form of knowledge influences behaviour, it may do so without the participant being aware of the sequential information, i.e. it is acquired implicitly. Evidence from physiological and lesion studies in animals and imaging studies in humans suggests that these two forms of learning may have dissociable neuronal substrates. Specifically, the striato-thalamo-cortical circuit centred on the caudate nucleus is proposed to be involved in intentional sequence learning and that based on the putamen on incidental learning. The present study tested one part of this proposed dissociation by assessing patients with Huntington's disease on tasks of the two forms of learning. On the test of trial-and-error intentional learning there were marked deficits, which were closely related to disease progression and to measures of executive cognitive dysfunction. This finding was in contrast to the finding from the incidental learning task. Performance of the Huntington's disease group was essentially normal and unrelated to measures of disease progression and cognitive status. The results, although supportive of the proposed dual-system hypothesis, offer only partial confirmation. Further direct study is required using similar tasks in patients with putamenal disorder or lesions within the skeletomotor striato-thalamo-cortical circuit. (+info)
Dissociation and post-traumatic stress disorder: two prospective studies of road traffic accident survivors.
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BACKGROUND: Dissociative symptoms during trauma predict post-traumatic stress disorder (PTSD), but they are often transient. It is controversial whether they predict chronic PTSD over and above what can be predicted from other post-trauma symptoms. AIMS: To investigate prospectively the relationship between dissociative symptoms before, during and after a trauma and other psychological predictors, and chronic PTSD. METHOD: Two samples of 27 and 176 road traffic accident survivors were recruited. Patients were assessed shortly after the accident and followed at intervals over the next 6 months. Assessments included measures of dissociation, memory fragmentation, data-driven processing, rumination and PTSD symptoms. RESULTS: All measures of dissociation, particularly persistent dissociation 4 weeks after the accident, predicted chronic PTSD severity at 6 months. Dissociative symptoms predicted subsequent PTSD over and above the other PTSD symptom clusters. Memory fragmentation and data-driven processing also predicted PTSD. Rumination about the accident was among the strongest predictors of subsequent PTSD symptoms. CONCLUSIONS: Persistent dissociation and rumination 4 weeks after trauma are more useful in identifying those patients who are likely to develop chronic PTSD than initial reactions. (+info)
Flashbacks and post-traumatic stress disorder: the genesis of a 20th-century diagnosis.
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BACKGROUND: It has been argued that post-traumatic stress disorder (PTSD) is a timeless condition, which existed before it was codified in modern diagnostic classifications but was described by different names such as 'railway spine' and 'shellshock'. Others have suggested that PTSD is a novel presentation that has resulted from a modern interaction between trauma and culture. AIMS: To test whether one core symptom of PTSD, the flashback, has altered in prevalence over time in soldiers subjected to the intense stress of combat. METHOD: Random selections were made of UK servicemen who had fought in wars from 1854 onwards and who had been awarded war pensions for post-combat disorders. These were studied to evaluate the incidence of flashbacks in defined, at-risk populations. RESULTS: The incidence of flashbacks was significantly greater in the most recent cohort, veterans of the 1991 Persian Gulf War; flashbacks were conspicuous by their absence in ex-servicemen from the Boer War and the First and Second World Wars. CONCLUSIONS: Although this study raises questions about changing interpretations of post-traumatic illness, it supports the hypothesis that some of the characteristics of PTSD are culture-bound. Earlier conflicts showed a greater emphasis on somatic symptoms. (+info)
Revisiting the dissociation between singing and speaking in expressive aphasia.
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We investigated the production of sung and spoken utterances in a non-fluent patient, C.C., who had a severe expressive aphasia following a right-hemisphere stroke, but whose language comprehension and memory were relatively preserved. In experiment 1, C.C. repeated familiar song excerpts under four different conditions: spoken lyrics, sung lyrics on original melody, lyrics sung on new but familiar melody and melody sung to a neutral syllable "la". In experiment 2, C.C. repeated novel song excerpts under three different conditions: spoken lyrics, sung lyrics and sung-to-la melody. The mean number of words produced under the spoken and sung conditions did not differ significantly in either experiment. The mean number of notes produced was not different either in the sung-to-la and sung conditions, but was higher than the words produced, hence showing a dissociation between C.C.'s musical and verbal productions. Therefore, our findings do not support the claim that singing helps word production in non-fluent aphasic patients. Rather, they are consistent with the idea that verbal production, be it sung or spoken, result from the operation of same mechanisms. (+info)