Dietary supplementation with eicosapentaenoic acid in patients with schizophrenia : neuropsychological evaluation of cognitive functioning

Dippenaar, Henda (2002-03)

Thesis (MA)--University of Stellenbosch, 2002.

Thesis

ENGLISH ABSTRACT: Schizophrenia is known to produce positive (e.g. hallucinations) and negative symptoms (e.g. social withdrawal). Cognitive dysfunction has long been recognised as common in schizophrenia and is now accepted as a third cardinal feature, thought strongly to be associated with negative symptoms. While positive symptoms may respond well to antipsychotic medication, the negative symptoms have typically been resistant to all forms of intervention. A current study looking at the efficacy of Eicosapentaenoic Acid (EPA), indicated a potential for negative symptoms to improve, although not significantly (P=O.14). The purpose of this research was to expand the above mentioned study, by evaluating the potential of EPA for improving cognitive function in patients with schizophrenia. Forty patients diagnosed with schizophrenia were randomly ascribed to one of two groups in a 12 week, double-blind, placebo-controlled study. The following neuropsychological tests were administered to patients at baseline and end point: Mini Mental State Examination (MMSE); Rey Auditory-Verbal Learning Test (RAVLT); Visual Reproduction, Wechsler Memory Scale - Revised (VR, WMS-R); Rey-Osterreith Complex Figure Test (ROCFT); Trail Making Tests (TMT-A; TMTB); Controlled Oral Word Association Test (COWAT); Similarities, South African Wechsler Adult Intelligence Scale - Revised (Similarities, SAWAIS-R); Boston Naming Test (BNT). There were no overall significant differences in neuropsychological function between the experimental (EPA) and the control (Placebo) group. In some isolated tests the experimental group did significantly better than the control group, but for other tests the control group did significantly better than the experimental group. Large intragroup variation - particularly within the EPA group - was indicated. In the EPA group only one out of 25 independent neuropsychological test scores showed a significant correlation with the symptom severity on the Positive and Negative Syndrome Scale (PANSS) total score (% change). There were no significant correlations between any of the neuropsychological test scores in the EPA group and on the dyskinesia subscore of the Extrapyramidal Symptom Rating Scale (ESRS). There was no evidence to support the hypothesis that EPA improved cognitive functioning in patients with schizophrenia.

AFRIKAANSE OPSOMMING: Dit is bekend dat skisofrenie positiewe (bv. hallusinasies) en negatiewe simptome (bv. sosiale onttrekking) voortbring. Kognitiewe disfunksie word lank reeds beskou as algemeen in skisofrenie en word nou aanvaar as 'n derde kardinale eienskap wat sterk geassosieer word met negatiewe simptome. Terwyl positiewe simptome goed reageer op antipsigotiese medikasie, is die negatiewe simptome tipies meer weerstandig teen all vorme van intervensie. 'n Huidige studie wat die effektiwiteit van Eicosapentaenoic Acid (EPA) ondersoek, het 'n potensiaal vir die verbetering in negatiewe simptome aangedui, alhoewel nie beduidend nie (P=O.14). Die doel van hierdie navorsing was om bogenoemde studie uit te brei, deur te evalueer wat die potensiaal van EPA is om kognitiewe simptome in pasiente met skisofrenie te verbeter. Veertig pasiente gediagnoseer met skisofrenie is ewekansig toegewys aan een van twee groepe in 'n 12 weke, dubbel-blinde, plasebo-gekontroleerde studie. Die volgende neurosielkundige toetse is afgeneem op pasiente by basislyn en eindpunt: Mini Mental State Examination (MMSE); Rey Auditory-Verbal Learning Test (RAVLT); Visual Reproduction, Wechsler Memory Scale - Revised (VR, WMS-R); Rey-Osterreith Complex Figure Test (ROCFT); Trail Making Tests (TMT-A; TMT-B); Control/ed Oral Word Association Test (COWAT); Similarities, South African Wechsler Adult Intelligence Scale - Revised (Similarities, SAWAIS-R); Boston Naming Test (BNT). Daar was geen beduidende verskille in neurosielkundige funksionering tussen die eksperimentele (EPA) en kontrole (Plasebo) groep nie. In 'n paar geïsoleerde toetse het die eksperimentele groep beduidend beter as die kontrolegroep gevaar, maar op ander toetse het die kontrolegroep beduidend beter as die eksperimentele groep gevaar. Groot intragroep variansie - in veral die EPA groep is aangetref In die EPA groep het slegs een uit die 25 onafhanklike neurosielkundige toetstellings gedui op 'n beduidende korrelasie met die ems van simptome op die Positive and Negative Syndrome Scale (PANSS) totale telling (% verandering). Daar was geen beduidende korrelasie tussen enige van die neurosielkundige toetstellings in die EPA groep en op die diskinesie-subtelling op die Extrapyramidal Symptom Rating Scale (ESRS) nie. Daar was geen bewyse om die hipotese te steun dat EPA kognitiewe funksionering in pasiënte met skisofrenie verbeter nie.

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