Neurocognition and thought disorder : it’s association, temporal stability and outcome correlates in first-episode psychosis

Olivier, Marius Riaan (2015-04)

Thesis (PhD)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: Abstract Neurocognitive deficits and thought disorder in schizophrenia have generally been accepted as core features of the illness, yet their underlying relationship, response to treatment, and correlations with outcome remain unclear. Most of the studies to date have used cross-sectional designs and focussed on stable patients already on treatment. The purpose of this study was to assess changes in neurocognition and thought disorder in antipsychotic naïve or minimally treated first episode psychosis (FEP) patients, over the course of 12 months of treatment according to a standard algorithm with flupenthixol decanoate (FD) long acting injectable antipsychotic. This was a prospective, non-comparative, open-label, longitudinal study of 42 patients with FEP. There was an initial wash-out phase of up to 7 days after which treatment was initiated with oral flupenthixol, 1 to 4 mg/day for 1 week prior to when the first long-acting FD was given. The starting dose of FD was 10mg every second week, with dose increases allowed at 6-week intervals. The Matrics Consensus Cognitive Battery (MCCB) and Rorschach Percerptual Thinking Index (PTI) were used as the primary co-measures for the assessment of neurocognition, thought disorder and perceptual disturbances respectively, at baseline prior to treatment, at month 6 and month 12. The main findings of this study were as follows: we confirmed the presence of significant neurocognitive impairment, thought disorder and perceptual disturbances prior to treatment, with improvement in neurocognitive performance and thought disorder from baseline to 6 months, with form perception improving later between month 6 and month 12. Improvements in symptoms were associated with improvements in neurocognitive performance, thought disorder and perceptual disturbances but a degree of residual impairment was evident at month 12. This study confirmed the association between neurocognition and form perception per se as well as their relative stability in FEP after initial improvement with treatment. We found support for the correlation between the amount of improvement in neurocognition, thought and perceptual disorder with outcome. We found the Social and Occupational Functioning Scale (SOFAS) to be a more robust measure of social and functional outcome with highest level of education (HLOE), substance abuse, reasoning-and-problem solving, form perception and Rorschach PTI emerging as predictors in a best subset regression analysis. The findings of this study suggest that neurocognitive impairments, thought disorder and perceptual disturbances have both state and trait like features, that patients benefit from treatment with a low-dose FGA, and that residual neurocognitive and perceptual impairment after treatment may indicate persisting underlying cerebral pathology.

AFRIKAANSE OPSOMMING: Abstrak Neurokognitiewe inkortinge en gedagteproses versteuring in skisofrenie word algemeen aanvaar as kern eienskappe van die siekte, tog is die onderliggende verhouding, die respons op behandeling, en die verwantskap met uitkoms onduidelik. Die meeste studies het 'n oorkruis-deursnee navorsingontwerp gebruik en gefokus op stabiele pasiёnte wat reeds op behandeling was. Die doel van hierdie studie was om die verandering in neurokognisie, gedagte vesteuring en perseptuele inkortinge te meet in eersteepisode psigose pasiёnte wat behandeling naïef was, of wat minimale behandeling gekry het, oor die verloop van 12 maande, met die toediening van 'n langwerkende, lae dosis flupenthixol inspuiting. Hierdie was 'n prospektiewe, nie-vergelykende, oop etiket, longitudinale studie van 42 eerste episode psigose pasiёnte almal op behandeling volgens 'n vaste protokol. Daar was 'n inisiёle uitwas periode van tot 7 dae waarna behandeling begin is op orale flupethixol, 1 tot 4 mg/dag vir 1 week voordat die eerste langwerkende flupenthixol inspuiting toegedien was. Die aanvangsdosis was 10mg elke tweede week met verhogings in dosis elke sesde week daarna. Die "Matrics Consensus Cognitive Battery'' (MCCB) en Rorschach "Perceptual Thinking Index" (PTI) is gebruik as die primêre instrumente vir die meting van neurokognisie, gedagte versteuring en perseptuele inkorting in noue samehang voor aanvang van behandeling, op maand 6 en op maand 12. Die hoof bevindinge van hierdie studie was as volg: Ons het die teenwoordigheid van beduidende neurokognitiewe, gedagte versteuring en perseptuele inkortinge bevestig voor behandeling, met verbetering in neurokognitiewe prestasie en gedagte versteuring tussen basislyn en maand 6, en verbetering in vorm persepsie wat later gevolg het tussen maand 6 en maand 12. Die verbetering in simptome was geassosieёr met verbetering in neurokognitiewe prestasie, gedagte versteuring en perseptuele inkortinge maar teen maand 12 was 'n graad van residuele neurokognitiewe en perseptuele inkortinge aanwesig. Hierdie studie het die verwantskap tussen neurokognisie en vorm persepsie bevestig, asook die relatiewe stabiliteit daarvan in eerste episode psigose na aanvanklike verbetering op behandeling. Ons het bewyse gevind wat die korrelasie tussen neurokognisie, gedagte en perseptuele versteuring met uitkomste ondersteun. Ons het bevind dat die "Social and Occuapational Functioning Scale" (SOFAS) 'n meer robuuste meting van sosiale en funksionele uitkoms is, en dat hoogste opvoedkundige vlak, substans misbruik, redenering-en-probleem oplossing, vorm persepsie en die Rorschach PTI as voorspellers identifiseer was in 'n beste substel regressie analise. Die bevindinge van hierdie studie suggereer dat neurokognitiewe, gedagte versteuringe en perseptuele inkortinge oor beide toestand en trek eienskappe beskik, en dat pasiёnte verbeter het met behandeling op 'n lae dosis eerste generasie antipsigotikum, en dat residuele neurokognitiewe en perseptuele inkortinge na behandeling aanduidend kan wees van onderliggende serebrale patologie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/97079
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