title: Excitability of the motor cortex in schizophrenia following typical and atypical antipsychotics: two serial case reports.
abstract: A previous electrophysiological investigation of schizophrenia using transcranial magnetic stimulation has shown altered corticospinal inhibition in medicated patients compared with drug-naive patients. Based on this work, we have carried out the first serial electrophysiological case studies of the human corticospinal system in schizophrenia in which a typical antipsychotic was compared with an atypical antipsychotic. We used transcranial magnetic stimulation-based techniques to study the time course of drug action in two antipsychotic drug-naive patients with schizophrenia; one patient treated with a typical antipsychotic (haloperidol) and the other with an atypical antipsychotic (risperidone). The typical antipsychotic was associated with an increase in corticospinal excitability which we found to occur 4-5 weeks after beginning medication. In contrast, the atypical antipsychotic was associated with a decrease in corticospinal excitability, occurring 3-4 weeks after starting pharmacotherapy. We conclude that these opposite neurophysiological effects are related to the relative dopaminergic and serotonergic actions of the two classes of drug.
authors.affiliation: MRC Clinical Sciences Centre, Hammersmith Hospital, London, UK.
authors.forename: B K
authors.initials: BK
authors.lastname: Puri
authors.forename: N J
authors.initials: NJ
authors.lastname: Davey
authors.forename: R
authors.initials: R
authors.lastname: Zaman
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D004574:Electromagnetic Fields; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000187:drug effects*; D006220:Haloperidol / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000187:drug effects* / Q000502:physiology; D011569:Psychiatric Status Rating Scales; D018967:Risperidone / Q000627:therapeutic use*; D012559:Schizophrenia / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D014150:Antipsychotic Agents; D006220:Haloperidol; D018967:Risperidone