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

The few existing long-term, neuropsychological follow-up studies of early onset schizophrenia (EOS) patients have reported relative stability in some cognitive functions but abnormal developmental trajectories in verbal memory, set shifting, aspects of attention, and speed of information processing throughout late adolescence into early adulthood. The current 5-year follow-up study compared the development of specific cognitive functions in EOS patients (N = 17) from the time of first-episode to chronic phase with that of healthy controls (N = 38) and secondarily to patients with other early onset, non-organic, non-affective psychoses (EOP) (N = 11). Speed of processing of executive functions, set shifting, and attention improved significantly in the healthy controls and reflected continuous functional maturation during late adolescence and early adulthood. The developmental progression of attention and set shifting but not speed of processing of executive functions was significantly subnormal in EOS patients. Other specific cognitive functions that had attained functional maturity in the healthy controls before or around the time of the baseline assessment showed normal development in EOS patients during the follow-up period, indicating stable cognitive deficits. These results suggest post-onset developmental deficits in two out of the three aspects of attention and executive functions that have protracted maturational trajectories and that overlap the age of onset of EOS. No significant difference in the development of any specific cognitive function was found between the EOS and EOP group.

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

Only few prospective longitudinal studies have assessed the course of intelligence deficits in early onset schizophrenia (EOS), and these have used different age appropriate versions of Wechsler Intelligence Scales and age appropriate norms. The post-psychotic development of intelligence in EOS has predominantly been characterized as relatively stable in these studies. However, comparisons of IQs from different test versions based on the different norms may not permit unequivocal interpretations. The objective of the current study was to compare the development of intelligence in EOS patients (N = 10) from their first psychotic episode to 5 years of post onset with that of healthy controls (N = 35) and patients who at baseline had been diagnosed with other non-affective psychoses (N = 8). The same version of a Wechsler Intelligence Scale was administered at both baseline and follow-up assessments, and the same norms were used to derive IQs at baseline and follow-up. Significantly smaller change in mean full scale intelligence quotient (FSIQ) was found in diagnostically stable EOS patients compared with healthy controls during the follow-up period. However, no statistically significant difference in mean FSIQ change was observed between patients with EOS and patients with other non-affective psychoses, although this result must be interpreted with caution due to the small sample sizes. The results suggest abnormally slow acquisition of new intellectual information and skills in EOS patients during the first 5 years after full clinical presentation.