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Open accessJournal ArticleDOI: 10.1080/13218719.2020.1767720

An Inventory of Problems–29 (IOP–29) study investigating feigned schizophrenia and random responding in a British community sample

04 Mar 2021-Psychiatry, Psychology and Law (Routledge)-Vol. 28, Iss: 2, pp 235-254
Abstract: Compared to other Western countries, malingering research is still relatively scarce in the United Kingdom, partly because only a few brief and easy-to-use symptom validity tests (SVTs) have been v...

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Topics: Malingering (61%), Schizotypy (54%)
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Open access
01 Jun 2009-
Abstract: 본 연구의 목적은 형사사법 현장에서 정신병리의 가장을 탐지하기 위해 고안된 M-FAST(Miller Forensic Assessment of Symptoms Test)를 국내에 소개하고, M-FAST의 신뢰도 및 타당도 검증을 통해 본 검사도구가 국내 표본을 대상으로 꾀병 탐지에 있어 적합한 지를 알아보는데 있다. 이를 위하여 K대학교에서 교양강좌를 수강하는 대학생(n=92), 그리고 국립 법무병원에서 정신감정으로 인해 입원해 있는 범죄자 집단(n=66)의 M-FAST 실시 자료가 분석에 사용되었다. M-FAST 전체 25문항의 내적 일치도는 신뢰도 계수 .90으로 매우 높은 것으로 나타났다. 또한 M-FAST의 7요인 구조에 대한 확인적 요인 분석이 실시되었다. 한편, MMPI-2 타당도 척도와의 상관관계 분석을 통하여 준거관련 타당도의 증거 또한 확인하였다. 전체 실험 참자가를 꾀병 집단과 솔직 응답 집단으로 재분류하여 M-FAST의 변별력을 살펴본 결과, M-FAST 총점과 모든 하위 척도에서 꾀병 집단이 솔직 응답 집단보다 유의하게 더 높은 점수를 보인 것으로 나타났다. 한편, ROC 분석 결과 M-FAST의 AUC는 .949로, 표준오차는 .017, p<.001, 95% 신뢰구간은 .9151에서 .982의 범위로 나타나 솔직 응답 집단과 꾀병 집단을 M-FAST가 효과적으로 구분하고 있는 것으로 나타났으며, M-FAST 총점의 변별 기준점이 6점이었을 때 예측 정확률은 최대가 되는 것으로 확인되었다.

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45 Citations




Journal ArticleDOI: 10.1080/23279095.2020.1864375
Abstract: We investigated the classification accuracy of the Inventory of Problems − 29 (IOP-29), its newly developed memory module (IOP-M) and the Fifteen Item Test (FIT) in an Australian community sample (...

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7 Citations


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Open accessBook
Jacob Cohen1Institutions (1)
01 Dec 1969-
Abstract: Contents: Prefaces. The Concepts of Power Analysis. The t-Test for Means. The Significance of a Product Moment rs (subscript s). Differences Between Correlation Coefficients. The Test That a Proportion is .50 and the Sign Test. Differences Between Proportions. Chi-Square Tests for Goodness of Fit and Contingency Tables. The Analysis of Variance and Covariance. Multiple Regression and Correlation Analysis. Set Correlation and Multivariate Methods. Some Issues in Power Analysis. Computational Procedures.

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Topics: Goodness of fit (61%), Contingency table (57%), Effect size (56%) ... read more

103,911 Citations


Open accessJournal ArticleDOI: 10.1016/J.PSYCHRES.2011.06.006
Vijay A. Mittal1, Elaine F. Walker2Institutions (2)
Abstract: Given the recent attention to movement abnormalities in psychosis spectrum disorders (e.g., prodromal/high-risk syndromes, schizophrenia) (Mittal et al., 2008; Pappa and Dazzan, 2009), and an ongoing discussion pertaining to revisions of the Diagnostic and Statistical Manuel of Mental Disorders (DSM) for the upcoming 5th edition, we would like to take this opportunity to highlight an issue concerning the criteria for tic disorders, and how this might affect classification of dyskinesias in psychotic spectrum disorders. Rapid, non-rhythmic, abnormal movements can appear in psychosis spectrum disorders, as well as in a host of commonly co-occurring conditions, including Tourette’s Syndrome and Transient Tic Disorder (Kerbeshian et al., 2009). Confusion can arise when it becomes necessary to determine whether an observed movement (e.g., a sudden head jerk) represents a spontaneous dyskinesia (i.e., spontaneous transient chorea, athetosis, dystonia, ballismus involving muscle groups of the arms, legs, trunk, face, and/or neck) or a tic (i.e., stereotypic or patterned movements defined by the relationship to voluntary movement, acute and chronic time course, and sensory urges). Indeed, dyskinetic movements such as dystonia (i.e., sustained muscle contractions, usually producing twisting and repetitive movements or abnormal postures or positions) closely resemble tics in a patterned appearance, and may only be visually discernable by attending to timing differences (Gilbert, 2006). When turning to the current DSM-IV TR for clarification, the description reads: “Tic Disorders must be distinguished from other types of abnormal movements that may accompany general medical conditions (e.g., Huntington’s disease, stroke, Lesch-Nyhan syndrome, Wilson’s disease, Sydenham’s chorea, multiple sclerosis, postviral encephalitis, head injury) and from abnormal movements that are due to the direct effects of a substance (e.g., a neuroleptic medication)”. However, as it is written, it is unclear if psychosis falls under one such exclusionary medical disorder. The “direct effects of a substance” criteria, referencing neuroleptic medications, further contributes to the uncertainty around this issue. As a result, ruling-out or differentiating tics in psychosis spectrum disorders is at best, a murky endeavor. Historically, the advent of antipsychotic medication in the 1950s has contributed to the confusion about movement signs in psychiatric populations. Because neuroleptic medications produce characteristic movement disorder in some patients (i.e. extrapyramidal side effects), drug-induced movement disturbances have been the focus of research attention in psychotic disorders. However, accumulating data have documented that spontaneous dyskinesias, including choreoathetodic movements, can occur in medication naive adults with schizophrenia spectrum disorders (Pappa and Dazzan, 2009), as well as healthy first-degree relatives of chronically ill schizophrenia patients (McCreadie et al., 2003). Taken together, this suggests that movement abnormalities may reflect pathogenic processes underlying some psychotic disorders (Mittal et al., 2008; Pappa and Dazzan, 2009). More specifically, because spontaneous hyperkinetic movements are believed to reflect abnormal striatal dopamine activity (DeLong and Wichmann, 2007), and dysfunction in this same circuit is also proposed to contribute to psychosis, it is possible that spontaneous dyskinesias serve as an outward manifestation of circuit dysfunction underlying some schizophrenia-spectrum symptoms (Walker, 1994). Further, because these movements precede the clinical onset of psychotic symptoms, sometimes occurring in early childhood (Walker, 1994), and may steadily increase during adolescence among populations at high-risk for schizophrenia (Mittal et al., 2008), observable dyskinesias could reflect a susceptibility that later interacts with environmental and neurodevelopmental factors, in the genesis of psychosis. In adolescents who meet criteria for a prodromal syndrome (i.e., the period preceding formal onset of psychotic disorders characterized by subtle attenuated positive symptoms coupled with a decline in functioning), there is sometimes a history of childhood conditions which are also characterized by suppressible tics or tic like movements (Niendam et al., 2009). On the other hand, differentiating between tics and dyskinesias has also complicated research on childhood disorders such as Tourette syndrome (Kompoliti and Goetz, 1998; Gilbert, 2006). We propose consideration of more explicit and operationalized criteria for differentiating tics and dyskinesias, based on empirically derived understanding of neural mechanisms. Further, revisions of the DSM should allow for the possibility that movement abnormalities might reflect neuropathologic processes underlying the etiology of psychosis for a subgroup of patients. Psychotic disorders might also be included among the medical disorders that are considered a rule-out for tics. Related to this, the reliability of movement assessment needs to be improved, and this may require more training for mental health professionals in movement symptoms. Although standardized assessment of movement and neurological abnormalities is common in research settings, it has been proposed that an examination of neuromotor signs should figure in the assessment of any patient, and be as much a part of the patient assessment as the mental state examination (Picchioni and Dazzan, 2009). To this end it is important for researchers and clinicians to be aware of differentiating characteristics for these two classes of abnormal movement. For example, tics tend to be more complex than myoclonic twitches, and less flowing than choreoathetodic movements (Kompoliti and Goetz, 1998). Patients with tics often describe a sensory premonition or urge to perform a tic, and the ability to postpone tics at the cost of rising inner tension (Gilbert, 2006). For example, one study showed that patients with tic disorders could accurately distinguish tics from other movement abnormalities based on the subjective experience of some voluntary control of tics (Lang, 1991). Another differentiating factor derives from the relationship of the movement in question to other voluntary movements. Tics in one body area rarely occur during purposeful and voluntary movements in that same body area whereas dyskinesia are often exacerbated by voluntary movement (Gilbert, 2006). Finally, it is noteworthy that tics wax and wane in frequency and intensity and migrate in location over time, often becoming more complex and peaking between the ages of 9 and 14 years (Gilbert, 2006). In the case of dyskinesias among youth at-risk for psychosis, there is evidence that the movements tend to increase in severity and frequency as the individual approaches the mean age of conversion to schizophrenia spectrum disorders (Mittal et al., 2008). As revisions to the DSM are currently underway in preparation for the new edition (DSM V), we encourage greater attention to the important, though often subtle, distinctions among subtypes of movement abnormalities and their association with psychiatric syndromes.

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Topics: Tics (65%), Tourette syndrome (62%), Dyskinesia (59%) ... read more

52,117 Citations



Open accessJournal ArticleDOI: 10.18637/JSS.V067.I01
Abstract: Maximum likelihood or restricted maximum likelihood (REML) estimates of the parameters in linear mixed-effects models can be determined using the lmer function in the lme4 package for R. As for most model-fitting functions in R, the model is described in an lmer call by a formula, in this case including both fixed- and random-effects terms. The formula and data together determine a numerical representation of the model from which the profiled deviance or the profiled REML criterion can be evaluated as a function of some of the model parameters. The appropriate criterion is optimized, using one of the constrained optimization functions in R, to provide the parameter estimates. We describe the structure of the model, the steps in evaluating the profiled deviance or REML criterion, and the structure of classes or types that represents such a model. Sufficient detail is included to allow specialization of these structures by users who wish to write functions to fit specialized linear mixed models, such as models incorporating pedigrees or smoothing splines, that are not easily expressible in the formula language used by lmer.

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37,650 Citations


Open accessBook
29 Nov 2010-
Abstract: Preface 1. Getting Started With R 2. Reading and Manipulating Data 3. Exploring and Transforming Data 4. Fitting Linear Models 5. Fitting Generalized Linear Models 6. Diagnosing Problems in Linear and Generalized Linear Models 7. Drawing Graphs 8. Writing Programs References Author Index Subject Index Command Index Data Set Index Package Index About the Authors

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Topics: Linear model (54%), Generalized linear model (51%)

7,889 Citations