Neuropsychological evidence supporting a neurodevelopmental model of schizophrenia: a longitudinal study

Abstract

The stability of neuropsychological performance in schizophrenia and its relationship to clinical change was contrasted between 60 patients with schizophrenia (30 first-episode, 30 previously treated) and 38 healthy controls using a comprehensive neuropsychological battery and clinical scales administered at intake and at a 19-month follow-up. Consistent with the neurodevelopmental model of schizophrenia, patients demonstrated deficits in cognitive performance at initial testing and did not show decline at follow-up. There were no differences in neuropsychological performance over time between first-episode and previously treated patients, nor between male and female patients or controls. As expected, patients improved clinically with treatment with respect to both positive and negative symptoms. First-episode patients improved more on the positive symptoms of hallucination and delusion; male and female patients showed equivalent clinical improvement. Clinical improvement correlated positively with neuropsychological change, with improved negative symptomatology accounting for most of the significant correlations.

Computerized Neurocognitive Scanning: II. The Profile of Schizophrenia

“…Thus, it seems that the neurocognitive performance measures of women are more sensitive to the effects of clinical variables; whereas, in men, variability related to clinical factors primarily influences speed of processing. Our results are consistent with earlier studies both in showing small-to-moderate correlations between neurocognitive measures and clinical variables (Censits et al 1997) and in suggesting that gender moderates these relationships (Goldstein et al 1998). The possibility that these variables affect speed more than accuracy in men merits further investigation.…”

“…Premorbid Adjustment Scale (PAS, Harris 1975), and Quality of Life Scale (QOL, Henrichs et al 1984) assessed functioning. The traditional neuropsychological battery described in the companion paper ) was administered to participants according to established procedures by trained predoctoral and postdoctoral Fellows (Censits et al 1997;Ragland et al 1999Ragland et al ,2000Saykin et al 1991Saykin et al , 1994. The computerized neurocognitive scan was administered to all participants in a counterbalanced order within a week of each other.…”

“…Test scores were standardized (z-scores; mean ϭ 0, standard deviation ϭ 1), based on all healthy participants in our normative database, and grouped into summary measures by combining each subject's z-scores on tests assessing the same functional domain (Censits et al 1997;Saykin et al 1991). For the traditional battery, summary measures were calculated for abstraction and mental flexibility (ABF), attention (ATT), verbal memory (VMEM), spatial memory (SMEM), language abilities (LAN), spatial abilities (SPA), sensory functions (SEN), and motor speed (MOT).…”

“…This combined sample was also used to examine the associations with clinical measures of symptoms and functioning following established procedures (Censits et al 1997;Gur et al 1999). The performance on each neurocognitive domain was correlated with PAS, duration of illness, severity of global SANS and SAPS, and QOL.…”

“…Are they affected by treatment and relate to outcome? Studies addressing these questions have indicated that: neurocognitive deficits are apparent at first clinical presentation in neuroleptic-naive patients (Bilder et al 1992;Hoff et al 1991;Saykin et al 1994); while stable, some show improvement with treatment (Censits et al 1997), especially with atypical neuroleptics (Buchanan et al 1994;Daniel et al 1996;Green et al 1997;Hagger et al 1993); and they show limited relation to clinical symptoms (Censits et al 1997), but do relate to functional outcome (Bellack et al 1999;Green 1996).…”