title: The interplay of childhood behavior problems and IQ in the development of later schizophrenia and affective psychoses.
abstract: Schizophrenia and affective psychoses are both associated with impaired social functioning, but the extent to which childhood behavioral impairments are present prior to onset of illness is less well studied. Moreover, the concurrent relationship of childhood behavior problems and premorbid IQ with subsequent psychotic disorder has not been established. We investigated whether childhood behavior problems are associated with increased risk for adult schizophrenia or affective psychosis, independently and in combination with IQ. The study included individuals with schizophrenia (N=47), affective psychoses (N=45) and non-psychotic controls (N=1496) from the New England Family Study. Behavior problems were prospectively assessed from standardized clinician observations at ages 4 and 7. IQ was assessed with the Stanford-Binet at age 4 and the Wechsler Intelligence Scale for Children at age 7. We found externalizing problems at age 4 and externalizing and internalizing problems at age 7 were associated with later schizophrenia, and both internalizing and externalizing problems at ages 4 and 7 were associated with later development of affective psychoses. Lower IQ at ages 4 and 7 was associated with schizophrenia, while lower IQ was associated with affective psychoses at age 7 only. Examined simultaneously, both lower IQ and behavior problems remained associated with risk of schizophrenia, while only behavior problems remained associated with affective psychoses. Behavior problems appear to be a general marker of risk of adult psychotic disorder, while lower childhood IQ is more specific to risk of schizophrenia. Future research should clarify the premorbid evolution of behavior and cognitive problems into adult psychosis.
authors.affiliation: MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, UK. Electronic address: jessica.agnew-blais@kcl.ac.uk.
authors.forename: Jessica
authors.initials: J
authors.lastname: Agnew-Blais
authors.affiliation: Harvard Medical School, Department of Psychiatry, Massachusetts Mental Health Center, Division of Public Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA; Harvard Medical School, Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Seidman
authors.affiliation: Harvard Medical School, Laboratory for Psychiatric Biostatistics, McLean Hospital, Belmont, MA 02478, USA; Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Garrett M
authors.initials: GM
authors.lastname: Fitzmaurice
authors.affiliation: Harvard Medical School, Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA; Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetics Research, Massachusetts General Hospital, Boston, MA 02114, USA.
authors.forename: Jordan W
authors.initials: JW
authors.lastname: Smoller
authors.affiliation: Harvard Medical School, Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Department of Psychiatry, Division of Women's Health, Connors Center for Women's Health & Gender Biology, Boston, MA 02120, USA.
authors.forename: Jill M
authors.initials: JM
authors.lastname: Goldstein
authors.affiliation: Brown University, Department of Epidemiology, Providence, RI 02912, USA.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Buka
mesh_terms: D000328:Adult; D000341:Affective Disorders, Psychotic / Q000453:epidemiology* / Q000209:etiology; D002648:Child; D002653:Child Behavior Disorders / Q000453:epidemiology*; D002675:Child, Preschool; D005500:Follow-Up Studies; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D009511:New England / Q000453:epidemiology; D012559:Schizophrenia / Q000453:epidemiology* / Q000209:etiology
keywords: Affective psychosis; Childhood behavior problems; Premorbid IQ; Premorbid cognition; Schizophrenia