[Benzodiazepines and schizophrenia, a review of the literature]

AIn this work, the authors have analysed the principal studies on the interest in the use of benzodiazepines in schizophrenia. The first double-controlled study concerning this question was conducted in 1961. The results of the first studies are criticisable due to the variability of the diagnostic and clinical assessment criteria, as well as to the divergences between the different conclusions. Through this review of literature, the authors wish to clarify the questions and hypothesis raised specify certain therapeutic strategies. MECHANISM OF GABA-ERGIC TREATMENTS: The analysis of the principle works on this question provides evidence on the use of benzodiazepines in schizophrenia. By fixing on their receptors, benzodiazepines facilitate GABA-ergic transmission. GABA is an inhibitor neurotransmitter. The GABA stimulation induced by benzodiazepines may be at the origin of a reduction of the pre-synaptic release of dopamine in the mesolimbic region. The GABA stimulation may also delay the post-synaptic adaptation of the dopaminergic neurons to neuroleptics. This phenomenon may enhance the activity of neuroleptics in resistant schizophrenia. Benzodiazepines would also have an effect on the mesoprefrontocortical regions where neuroleptics may be less efficient. It is interesting to note that this cerebral region is particularly sensitive to stress. This effect of benzodiazepines on the mesoprefrontocortical region might explain a preferentially beneficial effect in patients who have radiographic signs consistent with prefroncortical atrophy, although this observation remains preliminary. BENZODIAZEPINES IN MONOTHERAPY: In monotherapy their action on productive and deficient psychotic symptoms is greatly discussed and not very convincing. The main studies in the use of benzodiazepines alone ) are heterogeneous for their diagnosis criteria, their methodology and their results. The conclusions of the publications are not totally clear, and different points are to be criticized: heterogeneity of assessment criteria, heterogeneity and variability of methodology, use of non standardized scales, most of the studies are open studies, variability of benzodiazepines dose. BENZODIAZEPINES IN ASSOCIATION WITH NEUROLEPTICS: In few controlled studies, most authors have underlined ) the advantage of the association of benzodiazepines with neuroleptics. This association may act either on positive symptoms (hallucinations, delusions) or on negative symptoms. The latent period and the length of the effect of benzodiazepines in the treatment of psychotic patients remain unclear. According to certain studies, the therapeutic effect may appear in a short time, and then disappear within the fourth week. The association of benzodiazepines with neuroleptics is particularly helpful for patients with great anxiety, whether they have neuroleptic intolerance or not. There is no robust convergence about the type of benzodiazepines and their optimal dose in the treatment of schizophrenia. Their use may permit a reduction in the neuroleptic dose. They could increase the plasma concentration of neuroleptics and they might act on the mesoprefrontocortical regions where there are fewer dopaminergic auto receptors. BENZODIAZEPINES AND ANXIETY IN SCHIZOPHRENIA: States of anxiety, and in particular panic disorders that would participate in the exacerbation of psychotic symptoms, would benefit from the use of benzodiazepines. Anxiety can be considered as a major symptom of schizophrenia: insecure feelings and impressions of threatening events are frequent during schizophrenia. Interpretations or brutal hallucinations can lead to the feeling of imminent catastrophe or anxiety. Nevertheless, anxious phenomenons are under-estimated for many reasons: on the one hand, positive symptoms may hide anxiety, and on the other, the symptoms that are observed in patients treated with neuroleptics are often attributed to the neuroleptic side effects rather than linked to anxiety. Benzodiazepines and catatonia - Lorazepam has demonstrated its efficacy on catatonia. This effect seems to be specific of small doses of lorazepam (<5 mg/day). It should be compared to the effect of zolpidem in the same conditions. This prescription should be limited to acute catatonia, with no effect on chronic catatonia. Benzodiazepines and neuroleptic side effects - The use of benzodiazepines to treat some side effects of neuroleptics such as akathesia is reported by certain authors but remains little explained. They may have no effect or only small effects on tardive dyskinesia, but could reduce their incidence with the use of the smallest doses of neuroleptics in association with benzodiazepines. Safety of use - The safety of use of benzodiazepines in schizophrenia, particularly in association with neuroleptics is admitted, however recommended precautions with clozapine are to be noted. Benzodiazepine combined with clozapine clearly increases the frequency of cardiovascular and respiratory accidents. Some studies point out the risk of behavioural desinhibition and dysphoria. Their use should also be limited to patients with good compliancy, in order to avoid exacerbation of symptoms in the case of brutal interruption of the treatment. Dependency, which is an important issue in the use of benzodiazepines, seems much lesser in schizophrenia than in personality disorders and anxiety. Conversely, some studies point out the benefits of benzodiazepine use in schizophrenia, with their efficacy in the treatment and prevention of drug abuse. Finally, benzodiazepines contribute to the establishment of a good patient-doctor relationship, and may guarantee enhanced treatment compliancy.