title: Verbal recall and recognition in twins discordant for schizophrenia.
abstract: The nature, neural underpinnings, and etiology of deficits in verbal declarative memory in patients with schizophrenia remain unclear. To examine the contributions of genes and environment to verbal recall and recognition performance in this disorder, the California Verbal Learning Test was administered to a large population-based Finnish twin sample, which included schizophrenic and schizoaffective patients, their non-ill monozygotic (MZ) and dizygotic (DZ) co-twins, and healthy control twins. Compared with controls, patients and their co-twins showed relatively greater performance deficits on free recall compared with recognition. Intra-pair differences between patients and their non-ill co-twins in hippocampal volume and memory performance were highly positively correlated. These findings are consistent with the view that genetic influences are associated with reduced verbal recall in schizophrenia, but that non-genetic influences further compromise these abnormalities in patients who manifest the full-blown schizophrenia phenotype, with this additional degree of disease-related declarative memory deficit mediated in part by hippocampal pathology.
authors.affiliation: Department of Psychology, UCLA, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095, USA. vanerp@psych.ucla.edu
authors.forename: Theo G M
authors.initials: TG
authors.lastname: van Erp
authors.forename: Sebastian
authors.initials: S
authors.lastname: Therman
authors.forename: Tiia
authors.initials: T
authors.lastname: Pirkola
authors.forename: Annamari
authors.initials: A
authors.lastname: Tuulio-Henriksson
authors.forename: David C
authors.initials: DC
authors.lastname: Glahn
authors.forename: Peter
authors.initials: P
authors.lastname: Bachman
authors.forename: Matti O
authors.initials: MO
authors.lastname: Huttunen
authors.forename: Jouko
authors.initials: J
authors.lastname: Lönnqvist
authors.forename: Marja
authors.initials: M
authors.lastname: Hietanen
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Markku
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: Tyrone D
authors.initials: TD
authors.lastname: Cannon
mesh_terms: D000328:Adult; D035061:Control Groups; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D005260:Female; D005387:Finland; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007807:Language Tests / Q000706:statistics & numerical data; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D011939:Mental Recall; D010641:Phenotype; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011618:Psychotic Disorders / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D021641:Recognition, Psychology; D012559:Schizophrenia / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D012565:Schizophrenic Psychology; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics; D014706:Verbal Learning