title: A meta-analysis of cortical inhibition and excitability using transcranial magnetic stimulation in psychiatric disorders.
abstract: OBJECTIVE
  To evaluate transcranial magnetic stimulation (TMS) measures of inhibition and excitation in obsessive-compulsive disorder (OCD), major depressive disorder (MDD) and schizophrenia (SCZ).
  
  
  METHODS
  Paradigms included: short-interval cortical inhibition (SICI), cortical silent period (CSP), resting motor threshold, intracortical facilitation, and motor evoked potential amplitude. A literature search was performed using PubMed, Ovid Medline, Embase Psychiatry and PsycINFO 1990 through April 2012.
  
  
  RESULTS
  A significant Hedge's g was found for decreased SICI (g=0.572, 95% confidence interval [0.179, 0.966], p=0.004), enhanced intracortical facilitation (g=0.446, 95% confidence interval [0.042, 0.849], p=0.030) and decreased CSP (g=-0.466, 95% confidence interval [-0.881, -0.052], p=0.027) within the OCD population. For MDD, significant effect sizes were demonstrated for decreased SICI (g=0.641, 95% confidence interval [0.384, 0.898], p=0.000) and shortened CSP (g=-1.232, 95% confidence interval [-1.530, -0.933], p=0.000). In SCZ, a significant Hedge's g was shown for decreased SICI (g=0.476, 95% confidence interval [0.331, 0.620], p=0.000).
  
  
  CONCLUSIONS
  Inhibitory deficits are a ubiquitous finding across OCD, MDD, SCZ and enhancement of intracortical facilitation is specific to OCD.
  
  
  CONCLUSIONS
  Provides a clear platform from which diagnostic procedures can be developed.
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Natasha
authors.initials: N
authors.lastname: Radhu
authors.forename: Danilo R
authors.initials: DR
authors.lastname: de Jesus
authors.forename: Lakshmi N
authors.initials: LN
authors.lastname: Ravindran
authors.forename: Anosha
authors.initials: A
authors.lastname: Zanjani
authors.forename: Paul B
authors.initials: PB
authors.lastname: Fitzgerald
authors.forename: Zafiris J
authors.initials: ZJ
authors.lastname: Daskalakis
mesh_terms: D016208:Databases, Factual / Q000706:statistics & numerical data; D003865:Major Depressive Disorder / Q000503:physiopathology; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000473:pathology* / Q000503:physiopathology; D009044:Motor Cortex / Q000503:physiopathology*; D009433:Neural Inhibition / Q000502:physiology*; D009771:Obsessive-Compulsive Disorder; D011930:Reaction Time; D012559:Schizophrenia / Q000503:physiopathology; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation