title: Effects of moderate-dose treatment with varenicline on neurobiological and cognitive biomarkers in smokers and nonsmokers with schizophrenia or schizoaffective disorder.
abstract: BACKGROUND
  The administration of nicotine transiently improves many neurobiological and cognitive functions in schizophrenia and schizoaffective disorder. It is not yet clear which nicotinic acetylcholine receptor (nAChR) subtype or subtypes are responsible for these seemingly pervasive nicotinic effects in schizophrenia and schizoaffective disorder.
  
  
  OBJECTIVE
  Because α4β2 is a key nAChR subtype for nicotinic actions, we investigated the effect of varenicline tartrate, a relatively specific α4β2 partial agonist and antagonist, on key biomarkers that are associated with schizophrenia and are previously shown to be responsive to nicotinic challenge in humans.
  
  
  METHODS
  A double-blind, parallel, randomized, placebo-controlled trial of patients with schizophrenia or schizoaffective disorder to examine the effects of varenicline on biomarkers at 2 weeks (short-term treatment) and 8 weeks (long-term treatment), using a slow titration and moderate dosing strategy for retaining α4β2-specific effects while minimizing adverse effects.
  
  
  METHODS
  Outpatient clinics.
  
  
  METHODS
  A total of 69 smoking and nonsmoking patients; 64 patients completed week 2, and 59 patients completed week 8. Intervention Varenicline.
  
  
  METHODS
  Prepulse inhibition, sensory gating, antisaccade, spatial working memory, eye tracking, processing speed, and sustained attention.
  
  
  RESULTS
  A moderate dose of varenicline (1) significantly reduced the P50 sensory gating deficit in nonsmokers after long-term treatment (P = .006), (2) reduced startle reactivity (P = .02) regardless of baseline smoking status, and (3) improved executive function by reducing the antisaccadic error rate (P = .03) regardless of smoking status. A moderate dose of varenicline had no significant effect on spatial working memory, predictive and maintenance pursuit measures, processing speed, or sustained attention by Conners' Continuous Performance Test. Clinically, there was no evidence of exacerbation of psychiatric symptoms, psychosis, depression, or suicidality using a gradual titration (1-mg daily dose).
  
  
  CONCLUSIONS
  Moderate-dose treatment with varenicline has a unique treatment profile on core schizophrenia-related biomarkers. Further development is warranted for specific nAChR compounds and dosing and duration strategies to target subgroups of schizophrenic patients with specific biological deficits.
authors.affiliation: Maryland Psychiatric Research Center, Baltimore, MD 21228, USA. ehong@mprc.umaryland.edu
authors.forename: L Elliot
authors.initials: LE
authors.lastname: Hong
authors.forename: Gunvant K
authors.initials: GK
authors.lastname: Thaker
authors.forename: Robert P
authors.initials: RP
authors.lastname: McMahon
authors.forename: Ann
authors.initials: A
authors.lastname: Summerfelt
authors.forename: Jill
authors.initials: J
authors.lastname: Rachbeisel
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Fuller
authors.forename: Ikwunga
authors.initials: I
authors.lastname: Wonodi
authors.forename: Robert W
authors.initials: RW
authors.lastname: Buchanan
authors.forename: Carol
authors.initials: C
authors.lastname: Myers
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Heishman
authors.forename: Jeff
authors.initials: J
authors.lastname: Yang
authors.forename: Adrienne
authors.initials: A
authors.lastname: Nye
mesh_terms: D000328:Adult; D001288:Attention / Q000187:drug effects; D001552:Benzazepines / Q000008:administration & dosage / Q000627:therapeutic use*; D015415:Biomarkers; D003071:Cognition / Q000187:drug effects*; D004311:Double-Blind Method; D005133:Eye Movements / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000187:drug effects; D008875:Middle Aged; D009483:Neuropsychological Tests; D018722:Nicotinic Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D011618:Psychotic Disorders / Q000150:complications / Q000188:drug therapy* / Q000523:psychology; D011810:Quinoxalines / Q000008:administration & dosage / Q000627:therapeutic use*; D013216:Reflex, Startle; D012559:Schizophrenia / Q000150:complications / Q000188:drug therapy*; D012565:Schizophrenic Psychology; D055139:Sensory Gating / Q000187:drug effects; D012907:Smoking / Q000188:drug therapy* / Q000523:psychology; D000068580:Varenicline
chemical_list: D001552:Benzazepines; D015415:Biomarkers; D018722:Nicotinic Agonists; D011810:Quinoxalines; D000068580:Varenicline