Tabac et schizophrénie : aspects épidémiologiques et cliniques

Patients with schizophrenia may use nicotine to reduce cognitive deficits and negative symptoms or neuroleptic side effects. Smoking may transiently alleviate negative symptoms in schizophrenic patients by increasing dopaminergic and glutamatergic neurotransmission in the prefrontal cortex. In patients with schizophrenia, nicotine improves some cognitive deficits: (1) sensory gating deficits and abnormalities in smooth pursuit eye movements associated with schizophrenia are transiently normalized with the administration of nicotine ; (2) high-dose nicotine transiently normalizes the abnormality in P50 inhibition in patients with schizophrenia and in their relatives; (3) in tasks that tax working memory and selective attention, nicotine may improve performance in schizophrenia patients by enhancing activation of and functional connectivity between brain regions that mediate task performance (Jacobsen et al. 2004; Paktar et al.2002); (4) cigarette smoking may selectively enhance visuospatial working memory and attentional deficits in smokers with schizophrenia. However, Harris et al., found that nicotine affects only the attention without effects of nicotine on learning, memory or visuospatial/constructional abilities. In addition, smoking could facilitate disinhibition in schizophrenic patients.