Effect of antipsychotics on cortical inhibition using transcranial magnetic stimulation.
Previous studies suggest that antipsychotic medications may alter cortical inhibition (CI). The current study was designed to determine if typical or atypical antipsychotics indeed alter CI in healthy subjects using three CI paradigms as measured with transcranial magnetic stimulation (TMS): short interval intracortical inhibition (SICI), cortical silent period (CSP) and transcallosal inhibition (TCI). CI was measured before, 6 and 24 h after being randomly assigned to receive a single dose of 2 mg haloperidol (n=8), 10 mg olanzapine (n=10) or placebo (n=9). There was no significant effect on any measure of CI at 6 and 24 h after receiving olanzapine, haloperidol or placebo. Moreover, no significant change in the motor threshold was observed across the three medication groups. Therefore, single administration of an antipsychotic has no effect on CI or resting motor threshold. Whether chronic, repeated administration of antipsychotics has effects on CI requires further investigation.
Daskalakis
Zafiris J
ZJ
Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada. Jeff_Daskalakis@camh.net.|Schizophrenia Program, Centre for Addiction and Mental Health, 7th Floor, Clarke Division, 250 College Street, Toronto, Ontario, Canada. Jeff_Daskalakis@camh.net.
Christensen
Bruce K
BK
Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
Chen
Robert
R
Division of Neurology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada.
Fitzgerald
Paul B
PB
Alfred Psychiatry Research Centre, The Alfred and Monash University Department of Psychological Medicine, Commercial Road, Melbourne, Victoria, Australia.
Zipursky
Robert B
RB
Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
Kapur
Shitij
S
Schizophrenia Program, Centre for Addiction and Mental Health, Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
D000328:Adult; D000704:Analysis of Variance; D014150:Antipsychotic Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D001569:Benzodiazepines / Q000493:pharmacokinetics / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects*; D004576:Electromyography; D005260:Female; D006207:Half-Life; D006220:Haloperidol / Q000493:pharmacokinetics / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077152:Olanzapine
D014150:Antipsychotic Agents; D001569:Benzodiazepines; D006220:Haloperidol; D000077152:Olanzapine