title: Acute effects of mecamylamine and varenicline on cognitive performance in non-smokers with and without schizophrenia.
abstract: BACKGROUND
  Nicotinic acetylcholine receptors (nAChRs) have been implicated in the pathophysiology of cognitive deficits in the domains of attention and memory in schizophrenia. While nicotinic agonists and antagonists have been proposed as smoking cessation aids, few comparisons have been made of these agents on cognitive performance in individuals with schizophrenia.
  
  
  OBJECTIVE
  This study investigated the acute effects of a nAChR antagonist, mecamylamine, and partial agonist, varenicline, on cognitive function in non-smokers with and without schizophrenia.
  
  
  METHODS
  Single oral doses of mecamylamine 10 mg, varenicline 1 mg, and placebo were administered 1 week apart in random order to adults with schizophrenia (n = 30) and to healthy volunteers (n = 41) in a double-blind, crossover design. The primary outcome of interest was sustained attention as assessed with hit reaction time variability (HRT-SD) on the identical pairs continuous performance test (CPT-IP).
  
  
  RESULTS
  Mecamylamine worsened performance on CPT-IP HRT-SD, a measure of attention, compared to varenicline in both groups. Performance on mecamylamine was worse than performance on both placebo and varenicline on several additional measures of attention, including CPT-IP hit reaction time (HRT) and random errors at various levels of task difficulty. There was a treatment by diagnosis interaction, such that mecamylamine worsened performance on CPT-IP 2-digit HRT, 3-digit random errors, and 4-digit hit rate compared to placebo and varenicline in participants with schizophrenia; effects not observed in controls.
  
  
  CONCLUSIONS
  These findings support a role for nAChRs in attention and suggest that those with schizophrenia may be particularly sensitive to nAChR blockade.
authors.affiliation: Center for Addiction Medicine, Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, 60 Staniford Street, Boston, MA, 02114, USA.
authors.forename: Sungwon
authors.initials: S
authors.lastname: Roh
authors.forename: Susanne S
authors.initials: SS
authors.lastname: Hoeppner
authors.forename: David
authors.initials: D
authors.lastname: Schoenfeld
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Fullerton
authors.forename: Luke E
authors.initials: LE
authors.lastname: Stoeckel
authors.forename: A Eden
authors.initials: AE
authors.lastname: Evins
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use; D001288:Attention / Q000187:drug effects; D001552:Benzazepines / Q000494:pharmacology*; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D018722:Nicotinic Agonists / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology*; D011810:Quinoxalines / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects; D012559:Schizophrenia / Q000188:drug therapy; D012565:Schizophrenic Psychology; D016540:Smoking Cessation; D013647:Task Performance and Analysis; D000068580:Varenicline
chemical_list: D014150:Antipsychotic Agents; D001552:Benzazepines; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011810:Quinoxalines; D008464:Mecamylamine; D000068580:Varenicline