California verbal learning test-ii performance in schizophrenia as a function of ascertainment strategy: Comparing the first and second phases of the consortium on the genetics of schizophrenia (COGS)

William S. Stone, Raquelle I. Mesholam-Gately, David L. Braff, Monica E. Calkins, Robert Freedman, Michael F. Green, Tiffany A. Greenwood, Raquel E. Gur, Ruben C. Gur, Laura C. Lazzeroni, Gregory A. Light, Keith H. Nuechterlein, Ann Olincy, Allen D. Radant, Larry J. Siever, Jeremy M. Silverman, Joyce Sprock, Catherine A. Sugar, Neal R. Swerdlow, Debby W. TsuangMing T. Tsuang, Bruce I. Turetsky, Larry J. Seidman

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The first phase of the Consortium on the Genetics of Schizophrenia (COGS-1) showed performance deficits in learning and memory on the California Verbal Learning Test, Second Edition (CVLT-II) in individuals with schizophrenia (SZ), compared to healthy comparison subjects (HCS). A question is whether the COGS-1 study, which used a family study design (i.e. studying relatively intact families), yielded "milder" SZ phenotypes than those acquired subsequently in the COGS-2 case-control design that did not recruit unaffected family members. CVLT-II performance was compared for the COGS-1 and COGS-2 samples. Analyses focused on learning, recall and recognition variables, with age, gender and education as covariates. Analyses of COGS-2 data explored effects of additional covariates and moderating factors in CVLT-II performance. 324 SZ subjects and 510 HCS had complete CVLT-II and covariate data in COGS-1, while 1356 SZ and 1036 HCS had complete data in COGS-2. Except for recognition memory, analysis of covariance showed significantly worse performance in COGS-2 on all CVLT-II variables for SZ and HCS, and remained significant in the presence of the covariates. Performance in each of the 5 learning trials differed significantly. However, effect sizes comparing cases and controls were comparable across the two studies. COGS-2 analyses confirmed SZ performance deficits despite effects of multiple significant covariates and moderating factors. CVLT-II performance was worse in COGS-2 than in COGS-1 for both the SZ and the HCS in this large cohort, likely due to cohort effects. Demographically corrected data yield a consistent pattern of performance across the two studies in SZ.

Original languageEnglish
Pages (from-to)32-37
Number of pages6
JournalSchizophrenia Research
Volume163
Issue number1-3
DOIs
StatePublished - 1 Apr 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2014.

Funding

This study was supported by grants R01-MH065571 , R01-MH065588 , R01-MH065562 , R01-MH065707 , R01-MH065554 , R01-MH065578 , R01-MH065558 , R01 MH86135 , and K01-MH087889 from the National Institute of Mental Health , and the Commonwealth of Massachusetts ( SCDMH82101008006 ). Genotyping services were provided by the Center for Inherited Disease Research (CIDR). CIDR is fully funded through a federal contract from the National Institutes of Health to The Johns Hopkins University, Contract Number HHSN268200782096C .

FundersFunder number
National Institutes of Health
National Institute of Mental HealthR01MH065707
Commonwealth of MassachusettsSCDMH82101008006
Johns Hopkins UniversityHHSN268200782096C

    Keywords

    • California verbal learning test
    • Endophenotype
    • Memory
    • Schizophrenia
    • Verbal learning

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