title: Neural correlates of adjunctive rivastigmine treatment to antipsychotics in schizophrenia: a randomized, placebo-controlled, double-blind fMRI study.
abstract: Facilitation of central cholinergic activity may form a potential treatment strategy for cognitive impairment in schizophrenia. In a randomized, placebo-controlled, double-blind, parallel-group design, we investigated the neural correlates of cognitive effects of rivastigmine, an acetylcholinesterase inhibitor, given as an add-on therapy to antipsychotic-treated schizophrenia patients. Thirty-six chronic schizophrenia patients with mild cognitive impairment took part. After 1 week on placebo (baseline), all patients entered a double-blind protocol; 18 were allocated to receive rivastigmine and 18 placebo for the next 12 weeks (final sample with usable imaging data: 11 patients on rivastigmine, 10 on placebo). All patients underwent functional magnetic resonance imaging during a parametric 'n-back' task, involving monitoring of dots in particular locations on a screen at a given delay from the original occurrence, twice: at baseline and 12 weeks post-rivastigmine/placebo treatment. Compared to placebo, rivastigmine produced only a small and non-significant improvement in task accuracy across all conditions with no change in response latency, and increased activity in the extrastriate visual cortex in areas associated with visual and spatial attention but not in any region within the working memory network. Our observations suggest that cholinergic enhancement with rivastigmine at doses known to be effective in Alzheimer's disease does not produce strong and clinically meaningful cognitive and neural changes in schizophrenia patients treated with atypical antipsychotics although the neural effects in terms of enhanced neuronal activity in regions associated with visual and spatial attention are consistent with those reported previously with cholinergic enhancement in healthy subjects.
authors.affiliation: Department of Psychology, Institute of Psychiatry, King's College London, London, UK. v.kumari@iop.kcl.ac.uk
authors.forename: Veena
authors.initials: V
authors.lastname: Kumari
authors.forename: Ingrid
authors.initials: I
authors.lastname: Aasen
authors.forename: Dominic
authors.initials: D
authors.lastname: ffytche
authors.forename: Steven C R
authors.initials: SC
authors.lastname: Williams
authors.forename: Tonmoy
authors.initials: T
authors.lastname: Sharma
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D001921:Brain / Q000473:pathology; D002540:Cerebral Cortex / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D018696:Neuroprotective Agents / Q000627:therapeutic use*; D048448:Phenylcarbamates / Q000627:therapeutic use*; D011569:Psychiatric Status Rating Scales; D011930:Reaction Time / Q000502:physiology; D000068836:Rivastigmine; D012559:Schizophrenia / Q000188:drug therapy* / Q000473:pathology*; D012907:Smoking / Q000473:pathology
chemical_list: D014150:Antipsychotic Agents; D018696:Neuroprotective Agents; D048448:Phenylcarbamates; D000068836:Rivastigmine