Longitudinal Assessment of Premorbid Cognitive Functioning in Patients With Schizophrenia Through Examination of Standardized Scholastic Test Performance

Abstract

Scholastic test scores at grades 4 and 8 were nonsignificantly below average in this group of children who later developed schizophrenia. However, test scores dropped significantly between grades 8 and 11. This corresponds to ages 13-16 years, or the onset of puberty. Poor or declining scholastic performance may be a precursor to the cognitive impairment seen during the first episode of illness.

Should cognitive impairment be included in the diagnostic criteria for schizophrenia?

“…These types of analyses will need to be completed on other diagnostic groups to compare the prevalence of cognitive impairment relative to expectations between patients with schizophrenia and other diagnoses. (31,32). However, individuals who will eventually develop schizophrenia also demonstrate decline on scholastic measures between early childhood and late adolescence (32).…”

The persistence of developmental markers in childhood and adolescence and risk for schizophrenic psychoses in adult life. A 34-year follow-up of the Northern Finland 1966 birth cohort

“…In the Philadelphia cohort of the National Collaborative Perinatal Project (Rosso et al, 2000) deviance on motor coordination at age 7 as well as unusual movements at ages 4 and 7 predicted adult schizophrenia, but there was no additional predictive value from assessments of motor functioning later in childhood (teenage years). In a prospective longitudinal study in Iowa, test scores in preschizophrenic children dropped significantly between ages 13-16 years (Fuller et al, 2002). Persistent, pan-developmental (neuromotor, language, cognition) impairment specifically associated with schizophreniform disorder was detected in early childhood in the Dunedin Multidiscliplinary Health and Developmental Survey (Cannon et al, 2002) where cases performed worse than controls on standard tests of motor skill at ages 3, 5, and 9 years but not at age 7 years.…”

“…Numerous studies of premorbid function have revealed abnormalities or developmental delays in neuromotor, cognitive, language, emotional or social functioning. (McNeil et al, 2000;Isohanni et al, 2000a;Jones, 2001;Fuller et al, 2002;Cannon et al, 2003). Jones et al (1994) studied the British 1946 birth cohort and found evidence of delayed motor and speech development by the age of 2 years in those children who developed schizophrenia as adults.…”

Neurodevelopmental origin of cognitive impairment in schizophrenia

“…Neurocognitive deficits are persistent characteristics of schizophrenia throughout the illness and are predictors of level of functioning (Green, 1996;Bora et al 2010;Kahn & Keefe, 2013). Several studies have provided evidence indicating that cognitive and intellectual deficits are evident early in neurodevelopment, well before the onset of psychosis (Fuller et al 2002;Reichenberg et al 2010;Kahn & Keefe, 2013). Evidence also suggests that cognitive deficits are stable at follow-up in both chronic and early years of the illness even though performance of schizophrenia patients might improve less than healthy controls at follow-up (Szöke et al 2008;Bora & Murray, 2013;Hedman et al 2013).…”