Encephale
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The nature of neuropsychological mechanisms underlying the clinical picture of obsessions and compulsions has not been clearly determined. A number of studies has emphasized the role of cognitive deficits, but diversity of methodology and overlapping of clinical sub-groups have not established a specific cognitive functioning of these patients. The studies carried out on executive functions have, however, helped to identify the important role that both inhibition and cognitive flexibility play in obsessive-compulsive (OC) symptoms. Most of them have found that a deficit of inhibition and alteration of cognitive flexibility could explain inflexibility and repetitive thoughts and actions typical of all types of OC disorders. The aim of the paper is to present the published data supporting the hypothesis of a specific role played by a deficit of inhibition and cognitive inflexibility. In the first, theoretical part, we present the neuropsychological approach emphasizing inhibition and lack of flexibility as a promising explanation of the functioning of OC disorders. In the second part, we will present studies using various measurements of inhibition and the results of which, therefore, support this hypothesis. ⋯ On the theoretical level, it is the model of attention that was used in explaining the OCD hypothesis. In the model of attention control of action, described by Norman, Shallice and Burgess, three systems were emphasized: one that takes care of routine actions, and the second that takes over the first in situations where automatic activities must stop in order to establish an attention control and therefore inhibit automatic responses. When selection of everyday and automatic activities is not sufficient to accomplish a task, it is the third system, that of cognitive control, which takes over. This supervisory attentional system operates in non-routine and ambiguous activities. The cognitive control is charged with detecting potential or emitted cognitive errors and resolving ambiguous situations. Neurocognitive studies show that cingular anterior cortex and prefrontal lateral cortex are engaged in ambiguous and conflicting situations. These two regions are considered essential for inhibition of routine actions, adjustment to change and, more generally, for an efficient and flexible behaviour. Repetitive nature of verification rituals in OCD could be explained in terms of lack of relationship between two systems, leaving in action the one that regulates automatic activities. Therefore, the rituals are considered to be under particular influence of the system which, being in charge of automatic actions, has a deficit in disengagement. Another model of attention, described by Posner, gives a further explanation of OCD. Mental inhibition has the capacity to treat information, either by applying strategies to control it (i.e. trying not to remember an unpleasant event) or leaving it to automatic control (i.e. incapacity to experience an emotion in relation to a particular event). In this way, the effort to suppress an intrusive thought is considered as controlled and deliberate cognitive treatment of emotionally charged information. In OCD, in the context of heightened anxiety, the assumed negative valence of information would influence habitual suppression of thought during controlled treatment. As a result, controlled efforts to suppress obsessions in emotionally stressful situations, would lead to the production of repetitive thoughts, as controlled treatment of information has failed in this action. On a clinical and experimental level, these studies have led to a better understanding and conceptualization of OCD. In spite of some conflicting results, there are concordant data in favour of hypotheses of the role of sub-cortical and frontal regions and their function in inhibition/desinhibition implied in the onset and maintenance of OCD. Functional neuroimagery anomalies are also in favour of the role of sub-cortical-frontal region in clinical manifestations of OCD. They are often associated with low performance in cognitive tasks, especially those implying frontal functions, which are, in turn, dependent on a necessary level of attention in order to guide or inhibit motor and cognitive programs.
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Comparative Study
[Validation of the dialectal Arabic version of Barratt's impulsivity scale, the BIS-11].
Impulsivity is a symptom of several disorders such as personality disorder, bipolar disorder, suicidal behaviour, substance use disorders, schizophrenia...Forensic psychiatry is particularly concerned with impulsivity. It increases the risk of violence among clinical populations and figures in various instruments such as the HCR-20, the VRAG and the PCL-R to assess violence risk. It is one of many dimensions that can lead to aggressive behaviour among psychiatric patients. The Barratt Impulsiveness Scale (BIS), in its 11th version, is a 30-item self-report instrument that helps assessing impulsivity trait among normal and clinical populations. The BIS is the most commonly administered self-assessment of impulsiveness. As of March 2009, there have been 551 citations of the BIS-11 among many publications. The purpose of the present study is to examine the psychometric properties of the Arabic translation of the BIS-11th version in a sample of the general population and to identify an eventual correlation between impulsivity and socio-demographic characteristics. ⋯ There is growing interest in the impulsivity concept. Forensic psychiatry is particularly concerned by impulsivity. In fact, it is related to psychiatric patients' violence. Impulsivity also reveals the problem of responsibility assessment in psychiatric expertise and the dangerousness of psychiatric patients. The Arabic version of the BIS-11 has a good apparent and internal consistency. This version could be useful in assessing psychiatric patient's dangerousness.
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The mortality rate in schizophrenia is 4.5 times higher than in the general population. Suicide is one of the main causes of premature death in this affection. Life time prevalence of this behavior ranges from 10 to 15%, which represents a risk 20 to 50 times higher than in the general population. In addition, 40 to 93% of patients who committed suicide had attempted suicide previously. Thus, assessment of correlated variables with suicide attempts is a fundamental issue for developing preventive and therapeutic strategies in suicidal behavior. To the best of our knowledge, no systematic study has yet investigated suicide attempts in an Arabic Muslim population with schizophrenia, although many authors have demonstrated cultural differences in socio-demographic and clinical variables related to suicide attempts within many geographic areas around the world. ⋯ Demographic variables as suggested by other studies are less valuable predictors of suicide attempts in patients with schizophrenia. Interventions for reducing such behavior should focus on clinical variables and integrate an early diagnosis of the disease, reduce positive psychotic symptoms and tobacco consumption, correct extrapyramidal signs and improve medication compliance.