Intelligence, educational attainment, and brain structure in those at familial high-risk for schizophrenia or bipolar disorder

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de Zwarte S. M. C., Brouwer R. M., Agartz I., Alda M., Alonso-Lana S., Bearden C. E., ...More

HUMAN BRAIN MAPPING, vol.43, no.1, pp.414-430, 2022 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 43 Issue: 1
  • Publication Date: 2022
  • Doi Number: 10.1002/hbm.25206
  • Journal Name: HUMAN BRAIN MAPPING
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Agricultural & Environmental Science Database, BIOSIS, EMBASE, MEDLINE, Psycinfo
  • Page Numbers: pp.414-430
  • Keywords: bipolar disorder, education, intelligence, neuroimaging, relatives, schizophrenia, GENOME-WIDE ASSOCIATION, SCHOOL PERFORMANCE, PREMORBID IQ, YOUNG-ADULTS, METAANALYSIS, INDIVIDUALS, RELATIVES, HERITABILITY, DISCORDANT, THICKNESS
  • Dokuz Eylül University Affiliated: Yes

Abstract

First-degree relatives of patients diagnosed with schizophrenia (SZ-FDRs) show similar patterns of brain abnormalities and cognitive alterations to patients, albeit with smaller effect sizes. First-degree relatives of patients diagnosed with bipolar disorder (BD-FDRs) show divergent patterns; on average, intracranial volume is larger compared to controls, and findings on cognitive alterations in BD-FDRs are inconsistent. Here, we performed a meta-analysis of global and regional brain measures (cortical and subcortical), current IQ, and educational attainment in 5,795 individuals (1,103 SZ-FDRs, 867 BD-FDRs, 2,190 controls, 942 schizophrenia patients, 693 bipolar patients) from 36 schizophrenia and/or bipolar disorder family cohorts, with standardized methods. Compared to controls, SZ-FDRs showed a pattern of widespread thinner cortex, while BD-FDRs had widespread larger cortical surface area. IQ was lower in SZ-FDRs (d= -0.42,p= 3 x 10(-5)), with weak evidence of IQ reductions among BD-FDRs (d= -0.23,p= .045). Both relative groups had similar educational attainment compared to controls. When adjusting for IQ or educational attainment, the group-effects on brain measures changed, albeit modestly. Changes were in the expected direction, with less pronounced brain abnormalities in SZ-FDRs and more pronounced effects in BD-FDRs. To conclude, SZ-FDRs and BD-FDRs show a differential pattern of structural brain abnormalities. In contrast, both had lower IQ scores and similar school achievements compared to controls. Given that brain differences between SZ-FDRs and BD-FDRs remain after adjusting for IQ or educational attainment, we suggest that differential brain developmental processes underlying predisposition for schizophrenia or bipolar disorder are likely independent of general cognitive impairment.