[Tranquilizer dependence: features and withdrawal reactions].
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Anti-Anxiety Agents↗
Biomedical subjects
A Mechri
Publications and source records attributed to A Mechri.
[Repeat suicide attempts: characteristics of repeaters versus first-time attempters admitted in the emergency of a Tunisian general hospital].
UNLABELLED: Repeat suicide attempts constitute a special problem in suicidology. It seems that the excess mortality by suicide is even higher among the suicide repeaters. The objectives of this study were to estimate repeat suicide attempts frequency among a sample of suicide attempters admitted in the University Hospital Emergency of Monastir (Tunisia), to compare their features to those of first-time attempters and to determine factors associated with repeat suicide. METHOD: A transversal survey involves a review of all patients committing suicide attempt and who are admitted in the emergency service during the second semester of 1999. Study variables included: demographic parameters, family and personal psychiatric history, axis I psychiatric disorder and circumstances of the present suicide attempt. Also, subjects were evaluated with the following scales: Montgomery and Asberg Depression Rating Scale (MADRS) and The Social Readjustment Rating Scale of Holms and Rahe. RESULT: Among the 90 suicide attempters, 42.2% (n = 38) had made at least one previous suicide attempt. More repeaters than first-time attempters were divorced or separated: 21.1% versus 5.8% (p = 0.05). Belonging to a numerous family (n > or = 4) was more frequent in the repeaters group: 73.7% versus 46.2% (p = 0.01). The two groups did not differ as to level of education but were significantly different with regard to their professional activity: 60.5% of repeaters were unemployed versus 34.6% of first-time attempters (p = 0.01). Repeaters had more loaded family psychiatric disorders: 26.3% versus 7.7% (p = 0.03). However there were practically no differences between repeaters and first-time attempters in regard of suicide in their families. Personal previous history of repeaters was characterized by frequency of psychiatric hospitalization: 50% versus 11.5% (p = 0.00005). Sexual abuse was more frequent in repeaters group but this difference was not significant. Alcohol and drug abuse were not frequent in the two groups. Concerning the actual suicide attempt, the most frequently diagnosed disorder was adjustment disorders. However depressive and psychotic disorders were significantly more frequent in the repeaters group: 34.2% versus 13.4% (p = 0.05). Repeaters had more frequently elevated scores (> 14) in MADRS: 71.1% versus 48.1% (p = 0.01), and raised intensity of stress factors lived during the six months preceding actual suicide attempt: 68.4% versus 42.3% (p = 0.04). Nevertheless we hadn't noticed any differences between the two groups regarding the methods used or the motives. CONCLUSION: Differences in the characteristics of repeaters and first-time attempters are therefore of interest when discussing future suicidal risk and should clear on preventive actions in order to face the increase of suicidal recidivism. A broad based, multidisciplinary intervention approach is recommended.
Adult↗
[Oxidative stress involvement in schizophrenia pathophysiology: a review].
BACKGROUND: Schizophrenia is a devastating psychiatric disorder with a broad range of behavioural and biologic manifestations. There are several clinical characteristics of the illness that have been consistently associated with poor premorbid adjustment, long duration of psychosis prior to treatment and prominent negative symptoms. The etiopathogenic mechanisms of lack of insight in patients with schizophrenia are to date unknown, although several hypotheses have been suggested. A point of convergence for the theoretical models occurs with regard to the neuronal membrane. Neuronal membrane contains a high proportion of polyunsaturated fatty acid and is the site for oxidative stress. Oxidative stress is a state when there is unbalance between the generation of reactive oxygen species and antioxidant defence capacity of the body. It is closely associated with a number of diseases including Parkinson's disease, Alzheimer-type dementia and Huntington's chorea. Accumulating evidence points to many interrelated mechanisms that increase production of reactive oxygen or decrease antioxidant protection in schizophrenic patients. OBJECTIVES: This review aims to summarize the perturbations in antioxidant protection systems during schizophrenia, their interrelationships with the characteristic clinics and therapeutics and the implications of these observations in the pathophysiology of schizophrenia are discussed. LITERATURE FINDINGS: In schizophrenia there is evidence for deregulation of free radical metabolism, as detected by abnormal activity of critical antioxidant enzymes (superoxide dismutase, glutathione peroxidase and catalase). Many studies conclude in the decrease in the activity of key antioxidant enzymes in schizophrenia. A few studies have examined levels of non enzymatic antioxidants such as plasma antioxidant proteins (albumin, bilirubine, uric acid) and trace elements. How showed decreased levels in schizophrenic patients. Others studies have provided evidence of oxidative membrane damage by examining levels of lipid peroxidation products. Such abnormalities have been associated with certain clinical symptoms and therapeutic features. Negative symptoms have been associated with low levels of GSH-Px. Positive symptoms have been positively correlated with SOD activity. Plasma TAS was significantly lower in drug-free and haloperidol treated patients with schizophrenia. A low erythrocyte SOD activity has been found in never-treated patients, but with haloperidol treatment, SOD activity increased. DISCUSSION: These results demonstrate altered membrane dynamics and antioxidant enzyme activity in schizophrenia. Membrane dysfunction can be secondary to free a radical-mediated pathology, and may contribute to specific aspects of the schizophrenia symptomatology. Membrane defects can significantly alter a broad range of membrane functions and presumably modify behavior through multiple downstream biological effects. Phospholipid metabolism in the brain may be perturbed in schizophrenia, with reduced amounts of phosphatidylcholins and phosphatidylethanolamine in post-mortem brain tissue from schizophrenic patients, and large amounts of lipofuscin-like materiel in the oligodendrocytes. The existence of these products within cell membranes results in an unstable membrane structure, altered membrane fluidity and permeability and impaired signal transduction. Recent findings suggest that multiple neurotransmitter systems may be faulty. CNS cells are more vulnerable to the toxic effects of free radicals because they have a high rate of catecholamine oxidative metabolic activity. Neurotransmitters, like glutamate, can induce the same metabolic processes that increase free radical production and can lead to impaired dopamine-glutamate balance. These results question the role of this imbalance in the biochemical basis evoked in the etipathogenic mechanisms of schizophrenia, as well as the role of antioxidants in the therapeutic strategy and their implication in preventive and early intervention approaches in populations at risk for schizophrenia.
Antioxidants↗
[Acute nuptial psychosis: apropos of 16 cases].
The marriage, an over-invested social event in our Maghrebin cultural context, can, in certain cases, generate major psychiatric disorders especially of psychotic types. The aim of our study is to describe the clinical specifications of these psychotic disorders and to discuss the surroundings and individuals factors incriminated in their genesis. Our retrospective study concerns sixteen patients suffering from acute psychotic disorders precipitated by marriage. Male subjects represented 75% of cases with an average age of 26.8 years. 62.5% of them have no psychiatric background. The disorders first appeared after the marriage in 75% of cases, often during the first week. 68% of cases have delirious syndrome. Schizophreniform and brief psychotic disorders were often reported. The importance of the cultural factors was particularly prominent in the starting of these disorders.
Adjustment Disorders↗
[Glutaminergic hypothesis of schizophrenia: clinical research studies with ketamine].
Several lines of evidence suggest that the glutamatergic N-methyl-D-aspartate (NMDA) receptor is involved in schizophrenia pathophysiology. Post-mortem studies have revealed a lower density of glutamatergic receptors in patients with schizophrenia. Other studies of cerebrospinal fluid reported lower levels of glutamate in patients with schizophrenia in healthy comparison subjects. The most compelling evidence is provided by the psychomimetic effects of the NMDA antagonists phencyclidine and ketamine. Recently, much interest has been given to the study related to the role of NMDA receptor in pathophysiology of schizophrenia by administration of sub-anesthetic doses of ketamine. A phencyclidine hydrochloride derivate, ketamine, is a dissociative anesthetic and a non competitive antagonist of the NMDA receptor. In healthy subjects, ketamine produces: 1) positive symptoms of psychosis, such as illusions, thought disorder and delusions; 2) negative symptoms similar to those associated with schizophrenia including blunted emotional responses, emotional detachment, and psychomotor retardation; 3) cognitive impairments, in particular impairments on tests of frontal cortical function including increased distractibility, reduced verbal fluency and poorer performance on the Wisconsin Card Sorting Test. During smooth pursuit eye tracking, ketamine induces nystagmus as well as abnormalities which are among the characteristics of schizophrenia. In patients with schizophrenia, the administration of ketamine produces an activation of their psychotic symptoms, which have striking similarities to symptoms of their usual psychotic episodes. Ketamine effects on memory and other cognitive functions in schizophrenic patients are controversial. The psychomimetic effects of ketamine are transitional, reversible and influenced by time, dose and administration conditions. Susceptibility to the psychotomimetic effects of ketamine is minimal or absent in children and becomes maximal in early adulthood. The similarity between ketamine effects and endogenous psychoses created interest in the capacity of antipsychotic medications to block ketamine effects. Haloperidol failed to block this ketamine-induced psychomimetic effects in healthy subjects and in schizophrenic patients. However, clozapine, the prototype of atypical antipsychotic agents significantly reduced the ketamine-induced increase in positive symptoms in schizophrenic patients. Recently, lamotrigine significantly decreased ketamine-induced positive and negative symptoms in healthy subjects. Brain regions responsible for NMDA-mediated psychosis have not been established. Using positron emission tomography and [18F] fluorodeoxyglucose, the sub-anesthetic ketamine administration produces bilateral increases in metabolic activity in the prefrontal cortex. In a [15O] H2O positron emission tomography study, ketamine selectively increases cerebral blood flow in the anterior cingulate cortex and reduces cerebral blood flow in the hippocampus and primary visual cortex. The mechanism of neuropsychiatric effects of sub-anesthetic ketamine is not clear. A dysfunction in glutamate-dopaminergic interactions has been suggested as a mechanism for these effects of ketamine. Ketamine has been reported to primarily block NMDA receptor complex giving support to a glutamate deficiency hypothesis in schizophrenia. In addition, ketamine caused increases in cortical and striatal synaptic dopamine concentrations. The effects of NMDA receptor antagonist administration are argued to support a neurobiological hypothesis of schizophrenia, which includes pathophysiology within several neurotransmitter systems, manifested in behavioral pathology. Pharmacological modulation of the effects of NMDA receptor antagonists, such as ketamine, may lead to development of novel therapeutic agents for psychiatric illnesses such as schizophrenia.
Brain↗
[Pharmacological modulation of the effects induced by ketamine at subanesthetic doses].
The similarity between ketamine effects and endogenous psychoses has created interest in the capacity of antipsychotic medications to block ketamine effects. In healthy subjects, a sub-anaesthetic single dose of lorazepam, typical neuroleptics, such as haloperidol, and atypical neuroleptics, such as clozapine and olanzapine, failed to block ketamine-induced positive and negative symptoms resembling schizophrenia. However, haloperidol is able to decrease ketamine-induced impairment in executive cognitive functions. Recently, lamotrigine reduced ketamine-induced psychotic symptoms, perceptual alterations, and cognitive impairments. In schizophrenic subjects, single doses of olanzapine do not decrease the effects of ketamine. However, long term treatment with clozapine has been reported to decrease ketamine-induced positive symptoms. Pharmacological modulation of the effects of NMDA receptor antagonists, such as ketamine, may lead to development of novel therapeutic agents for psychiatric illnesses such as schizophrenia.
Anesthetics, Dissociative↗
[Bipolarity correlated factors in major depression: about 155 Tunisian inpatients].
The distinction between the depressive troubles according to their inclusion in bipolar disorders or in recurrent depressive disorders offers an evident practical interest. In fact, the curative and mainly the preventive treatment of these troubles are different. So it is necessary to identify the predictive factors of bipolar development in case of inaugural depressive episode. In 1983, Akiskal was the first who identified those factors: pharmacological hypomania, puerperal depression, onset at early age (<25 years), presence of psychotic characteristics, hypersomnia and psychomotor inhibition. Through this study, the authors try to compare the epidemiological, clinical and evolution characteristics of major depression in bipolar disorders to recurrent depressive disorders in order to indicate the correlated factors with bipolarity. It is a retrospective and comparative study based on about 155 inpatients for major depressive episode during the period between January 1994 and December 1998. These patients were divided into two groups according the DSM IV criteria: bipolar group (96 patients) and recurrent depressive group (59 patients). Both groups were compared according to socio-demographic data, life events in childhood, personal and family history, clinical and evolution characteristics of the index depressive episode. The predictive factors proposed by Akiskal were systematically examined. It was found out that the following factors were correlated with bipolarity: high rate of separation and divorce (17.7% versus 5.1%; p=0.02), family history of psychiatric disorders (56.3% versus 35.6%; p=0.012) especially bipolar ones (29.2% versus 3.4%; p=0,00008), onset at early age (mean age of onset: 24.8 8.2 years versus 34.1 12.6 years; p=0.000004), number of affective episode significantly more frequent (mean 3.6 versus 2.5; p=0.03), sudden onset of depressive episode (44.8% versus 15.9%; p=0.0003) and presence of psychotic characteristics (69.8% versus 16.7%; p=0.0001) catatonic characteristics (37.3% versus 20.3%; p=0.03), hypersomnia (51% versus 20.3%; p=0.03) and psychomotor inhibition (83.3% versus 42.4%; p=0.00007). Negatively correlated factors of bipolar depression were: somatic comorbidity such as diabetes, hypertension and rhumatismal diseases (12.5% versus 28.8%; p=0.012) and association with dysthymic disorders (2.2% versus 12.1%; p=0.029). No correlation was found between bipolarity and life events in childhood, seasonal character, alcoholic dependence and suicide attempt. Concerning the validity of predictive factors of bipolarity proposed by Akiskal, we found: history of bipolar disorders (Sensibility: 29.2%, specificity: 96.6%, Positive Predictive Value (PPV): 93%), hypersomnia (Sensibility: 51%, specificity: 80%, PPV: 80%), onset before the age of 25 years (Sensibility: 62.5%, specificity: 70%, PPV: 77%), psychomotor inhibition (Sensibility: 83.3%, specificity 58%, PPV: 76%), and psychotic characteristics (Sensibility: 69.8%, specificity: 62.7%, PPV: 75%). In spite of methodological differences, our results tallied with the other studies. We focus on the importance of the bipolar family history criterion, which has the highest PPV, and the limits of psychotic characteristics criterion which has the lowest PPV. This may be explained by the frequency of these characteristics of affective disorders in our cultural context. The association of the hypersomnia and psychomotor inhibition in one criterion in order to increase their diagnostic power. Our study helps us to identify the factors that would predict the bipolar evolution of a depressive episode allowing the use of specific treatment and ensuring the improvement of prognostic.
Adult↗