The Maudsley Early Onset Schizophrenia Study: Cognitive Function Over a 4-Year Follow-Up Period

Abstract

Generalized cognitive deficits have been consistently reported in adolescents with early onset schizophrenia (EOS; defined as onset before the age of 17 years). The impact on cognition of potential interactions between disease pathology and brain maturation remains unclear. We therefore compared cognitive function between 20 EOS patients and 20 healthy controls matched on age, gender, and parental socioeconomic status at 2 time points, when aged 15.58 (2.27) and after a mean interval of 4 +/- 1.08 years when aged 19.46 (2.21) years. Repeated measures analyses revealed no differences between patients and controls in the degree of change over this time period in general intellectual function and planning ability as measured by the Tower of London. There was deterioration in the verbal memory and attentional control index scores from the Wechsler Memory Scale-Revised but relative improvement in Part A of the Trail Making Test. Patients' level of symptomatology as well as the type and dose of medication were comparable at both time points. We conclude that most aspects of cognitive function remain relatively stable in EOS patients during adolescence; there is evidence for deterioration in immediate verbal memory and attention while speed of information processing may show improvement.

Deficient maturation of aspects of attention and executive functions in early onset schizophrenia

“…The lack of significant differential development in verbal memory between EOS patients and healthy controls contrasts with previous findings [24]. However, we observed unexpected and significant deterioration of verbal memory in the healthy controls, and it is possible that tester-effects may explain this finding.…”

“…In continuation of these results on intelligence development, the focus of our current study is on the development of specific cognitive functions in EOS. Frangou et al (2008) reported a significant deterioration in immediate verbal memory and attention during the late adolescent years in EOS patients, while the performance in healthy controls improved. No differential change in the planning aspect of executive functions (EF) was observed, whereas information processing speed improved in EOS but not in controls [24].…”

“…Frangou et al (2008) reported a significant deterioration in immediate verbal memory and attention during the late adolescent years in EOS patients, while the performance in healthy controls improved. No differential change in the planning aspect of executive functions (EF) was observed, whereas information processing speed improved in EOS but not in controls [24]. In an impressive 13 year follow-up study, a significant decline in verbal memory and a lack of improvement in speed of information processing and the set shifting aspect of EF have also been found in EOS patients as opposed to stability and improvement among healthy controls [64].…”

Course of intelligence deficits in early onset, first episode schizophrenia: a controlled, 5-year longitudinal study

“…years after the onset of psychosis [16]. This finding of long-term stability in FSIQ is corroborated by similar, minor and statistical significant improvements in age-corrected FSIQ in EOS patients and controls over a mean interval of 4 years [14]. A possible explanation for the different findings may be methodological since previous longitudinal studies of intelligence in EOS and COS administered age appropriate childhood and adult IQ test versions.…”

“…A recent longitudinal study used a case-control design to assess the development of deficits in several domains of cognitive functioning, including intelligence, in adolescent patients with EOS using two time points of assessments with a mean interval of 4 years. A statistically significant, but relatively small improvement in mean FSIQ was found in patients and controls with no significant between-group difference in amount of change [14]. These longitudinal studies used age appropriate versions of Wechsler Intelligence Scales and age appropriate norms that make assessments of IQ from childhood and well into adulthood possible.…”