Malingering in persons with a diagnosis of depression

De Villiers, Vesta Naomi (2000-12)

Thesis (MSc)--University of Stellenbosch, 2000.

Thesis

ENGLISH ABSTRACT: Malingering is the intentional production or exaggeration of symptoms for personal gain in the context of external incentives. Due to the absence of objective symptoms, depression may represent a relatively attractive option for malingerers. Existing approaches to distinguish between depressive symptoms and possible malingering often use time-consuming psychometric tests or unreliable interview techniques. Short screening tests for malingering may be a practicable alternative and recently South African cut-off scores on tests for malingering were determined for a student sample. The purpose of this study was to establish South African cut-off scores for persons with a diagnosis of depression on screening instruments for malingering. Fifty-one subjects with a diagnosis of depression (measured by the Zung Depression Scale) were randomly ascribed to one of two groups: an experimental group of 25 subjects (instructed to simulate symptoms based on a malingering case scenario) and a control group of 26 subjects (instructed to do their best in the tests). No incentive was provided to the subjects. Each subject completed the 21-item verbal memory forced choice test (FCT), the Rey IS-item test (Rey IS-item), the dot-counting test (DCT), the Word Recognition test (WR) that is part of the Alzheimer Disease Assessment Scale Cognitive Battery (ADAS-Cog) and the Structured Inventory of Malingered Symptomatology (SIMS). The WR test correctly classified 74.5% of subjects with a sensitivity of 93%. The FCT, with a cut-off of> 15.5, correctly classified 72.5% of subjects. A regression equation was computed by combining the FCT, DCT and SIMS. This correctly classified 74.5% of patients with a sensitivity of 69%. The DCT accurately identified 64% of the malingerers using a cut-off score of> 65.57. The Rey15-item test showed poor results and does not seem to be useful as a screening instrument. The WR test shows promise as a screening instrument for malingering. Combining tests when screening for malingering proved to be an effective way to distinguish between malingering of depressive symptoms and real symptoms. The results of this study will help provide guidelines to mental health workers on how to diagnose malingering in patients with depression more objectively.

AFRIKAANSE OPSOMMING: Malingering is die opsetlike nabootsing of oordrywing van simptome vir persoonlike gewin in die konteks van eksterne vergoeding. As gevolg van die subjektiewe aard van simptome, kan depressie 'n relatief aantreklike opsie wees wanneer psigiatriese kondisies gesimuleer word. Bestaande maniere om te onderskei tussen werklike depressiewe simptome en moontlike malingering, gebruik tydrowende psigometriese toetse of onbetroubare onderhoudstegnieke. Kort siftingstoetse vir malingering kan 'n praktiese altenatief wees en onlangse Suid-Afrikaanse afsnypunte op toetse vir malingering is bepaal vir 'n studentesteekproef. Die doel van hierdie studie was om Suid-Afrikaanse afsnypunte te verkry vir malingeringstoetse vir mense met 'n diagnose van depressie. Een en vyftig subjekte met 'n diagnose van depressie (gemeet deur die Zung Depressieskaal) is ewekansig toegewys aan een van twee groepe: 'n eksperimentele groep van 25 subjekte (met die opdrag om simptome te simuleer op grond van 'n malingering-scenario) en 'n kontrolegroep van 26 subjekte (met die opdrag om hulle bes te doen in die toetse). Geen vergoeding is aan proefpersone gebied nie. Elke subjek het die 21-item verbal memory forced choice test (FfC), die Rey 15-item test (Rey IS-item), die dot-counting test (DCT), die Word Recognition test (WR) wat deel vorm van die Alzheimer Disease Assessment Scale Cognitive Battery (ADAS-Cog) en die Structured Inventory of Malingered Symptomatology (SIMS) voltooi. Die WR het 74.5% van die subjekte korrek geklasifiseer met 'n sensitiwiteit van 93%. Die FCT, met 'n afsnypunt van <15.5, het 72.5% van die subjekte korrek geklassifiseer. 'n Regressie-vergelyking is bereken deur 'n kombinering van die FCT, DCT en SIMS. Dit het 74.5% van die subjekte korrek geklassifiseer met 'n sensitiwiteit van 69%. Die DeT kon 64% van die malingeerders akkuraat identifiseer deur gebruik te maak van 'n afsnypunt van> 65.57. Die Rey IS-item toets het swak resultate getoon en blyk nie bruikbaar te wees as 'n siftingstoets nie. Die WR toon potensiaal as In siftingstoets vir malingering. Die kombinering van toetse wanneer pasiënte gesif word vir malingering blyk 'n effektiewe manier te wees om te onderskei tussen die malingering van depressiewe simptome en werklike simptome. Die resultate van hierdie studie kan help om riglyne te skep vir geestesgesondheidswerkers oor hoe om malingering van depressie meer objektief te diagnoseer.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/51824
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