Factor analysis using the Generalisability Theory of PANSS data from clinical trials in schizophrenia and bipolar disorder

Factor analysis using the Generalisability Theory of PANSS data from clinical trials in schizophrenia and bipolar disorder

The Positive and Negative Symptom Scale (PANSS) is a widely used 30-item rating scale developed for clinicians to assess the presence of positive symptoms, negative symptoms and general psychopathology in people with schizophrenia. The PANSS generally has good reliability and validity although the internal consistency of the positive symptoms and general psychopathology subscales have been reported as ‘modest', and test-retest reliability ranged between .60 to .80 at subscale level. Further research is required to identify the sources of measurement error, which may also account for longitudinal variation in PANSS scores. This is of particular significance in clinical trials where clinical measures must be sensitive to true change in symptoms over time.A key issue for measuring change in psychopathological symptoms is the extent to which the underlying construct is stable or fluctuates over time. The differentiation between stable and dynamic aspects of schizophrenia is important for accurate diagnosis, monitoring and treatment of this condition. Therefore, the clinical measure must be temporally stable and free from measurement error. However, the conventionally Classical Test Theory (CTT) approaches to reliability, e.g. test-retest, do not account for specific factor error (idiosyncratic responding due to error caused by items unrelated to the construct of interest). Consequently observed changes in symptoms may be due to unwanted error as well as actual variation in symptoms.Generalisability or G Theory is an ideal method for evaluating specific sources of measurement error in clinical trials. CTT assumes that an observation is a combination of an individual's true score and random measurement error. Whereas G Theory uses analysis of variance (ANOVA) to calculate precise estimates for the error variance due to each important measurement facet. Facet refers to any distinct element that the researcher theorises might influence variance and error in test scores, and calculates reliability across those components concurrently. For example facets may be, the persons tested (P), the test items (I) and the testing occasion (O). In contrast CTT restricts analysis of reliability and error variance to a single element such as the test items (i.e., Cronbach's alpha), the occasion (test-retest) or the rater (inter-rater) and does not allow for simultaneous evaluation of true score estimates as there is no logical way to combine them. In G Theory terms, the variance associated with participants or persons is considered the central concern and is known as the differentiation facet with otThe Positive and Negative Symptom Scale (PANSS) is a widely used 30-item rating scale developed for clinicians to assess the presence of positive symptoms, negative symptoms and general psychopathology in people with schizophrenia. The PANSS generally has good reliability and validity although the internal consistency of the positive symptoms and general psychopathology subscales have been reported as ‘modest', and test-retest reliability ranged between .60 to .80 at subscale level. Further research is required to identify the sources of measurement error, which may also account for longitudinal variation in PANSS scores. This study aims to apply the Generalisability Theory to identify stable and dynamic symptom progression within the context of clinical trial data from patients diagnosed with schizophrenia to evaluate the psychometric properties of the PANSS, its subscales and individual items.

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Treatment of Schizophrenia" },{ "PostingID": 1651, "Title": "LILLY-F1D-EW-E003", "Description": "A Fixed-Dose Range Safety and Efficacy Study of Olanzapine
Versus Haloperidol in the Treatment of Schizophrenia" },{ "PostingID": 1652, "Title": "LILLY-F1D-MC-HGGI", "Description": "Olanzapine Relapse Prevention Versus Placebo in the Treatment of Schizophrenia" },{ "PostingID": 1653, "Title": "LILLY-F1D-MC-HGHD", "Description": "Olanzapine Versus Haloperidol in the Treatment of Acute Mania" },{ "PostingID": 1654, "Title": "LILLY-F1D-MC-HGJZ", "Description": "A Double-Blind Randomized Study Comparing Intramuscular Olanzapine Depot With Placebo in the Treatment of Patients With Schizophrenia" },{ "PostingID": 1829, "Title": "GSK-SCA101464", "Description": "A Multicenter, Randomized, Double-Blind, Parallel Group Study to Evaluate the Efficacy and Safety of a Flexible Dose of Lamotrigine Compared to Placebo as an Adjunctive Therapy to an Atypical Antipsychotic Agent(s) in Subjects with Schizophrenia" },{ "PostingID": 1830, "Title": "GSK-SCA30926", "Description": "A Multi-Center, Double blind, Placebo-controlled, Randomized, Parallel Group Evaluation of the Efficacy of a Flexible Dose of Lamotrigine versus Placebo As Add-On Therapy In Schizophrenia" },{ "PostingID": 1957, "Title": "LILLY-F1D-MC-HGHB", "Description": "A Double-Blind Randomised Comparison of the Efficacy and Safety of Short Acting Intramuscular Olanzapine, Short Acting Intramuscular Haloperidol and Intramuscular Placebo in Patients with Schizophrenia" },{ "PostingID": 1958, "Title": "LILLY-F1D-MC-HGHV", "Description": "A Double-Blind Dose-Response Study Comparing Short Acting Intramuscular Olanzapine, Short Acting Intramuscular Haloperidol and Intramuscular Placebo in Patients with Schizophrenia" },{ "PostingID": 1961, "Title": "LILLY-F1D-VI-HGCH", "Description": "Efficacy and Safety of Olanzapine Versus Fluphenazine" },{ "PostingID": 2015, "Title": "LILLY-F1D-MC-HGEH", "Description": "Olanzapine Versus Placebo in the Treatment of Mania Associated with Bipolar I Disorder" },{ "PostingID": 2016, "Title": "LILLY-F1D-MC-HGHL", "Description": "Olanzapine Versus Placebo in the Prevention of Relapse in Bipolar Disorder" },{ "PostingID": 2090, "Title": "LILLY-F1D-MC-HGFU", "Description": "Olanzapine Added to Mood
Stabilizers in the Treatment of Bipolar Disorder" },{ "PostingID": 2092, "Title": "LILLY-F1D-MC-HGGW", "Description": "Olanzapine Versus Placebo in the Treatment of Bipolar Disorder, Manic or Mixed" },{ "PostingID": 2094, "Title": "LILLY-F1D-MC-HGHT", "Description": "Olanzapine Versus Lithium in Relapse Prevention in Bipolar Disorder" },{ "PostingID": 2095, "Title": "LILLY-F1D-MC-HGIN", "Description": "Olanzapine Versus Placebo in the Treatment of Adolescents With Schizophrenia" },{ "PostingID": 2099, "Title": "LILLY-F1D-SB-LOAY", "Description": "Open-label Study on the Efficacy and Safety of Olanzapine in Adolescent and Young Adult Patients with Schizophrenia, Schizoaffective and Schizophreniform Disorders" },{ "PostingID": 2100, "Title": "LILLY-F1D-US-HGHQ", "Description": "Olanzapine Versus Divalproex in the Treatment of Acute Mania" },{ "PostingID": 2101, "Title": "LILLY-F1D-MC-HGKA", "Description": "A Double-Blind, Randomized Study Comparing Intramuscular Olanzapine Depot to Oral Olanzapine and Low-Dose Depot in the Maintenance Therapy of Patients With Schizophrenia" },{ "PostingID": 2102, "Title": "LILLY-F1D-MC-HGKB", "Description": "An Open-Label Study of Intramuscular Olanzapine Depot in Patients With Schizophrenia or Schizoaffective Disorder" },{ "PostingID": 4003, "Title": "LILLY-F1D-MC-HGGN", "Description": "The Comparative Efficacy of Olanzapine, Risperidone, and Haloperidol for Cognition in Schizophrenia" },{ "PostingID": 4004, "Title": "LILLY-F1D-MC-HGDH", "Description": "The Acute and Long-Term Efficacy of Olanzapine in First-Episode Psychotic Disorders: A Randomized Double-Blind Comparison with Haloperidol" },{ "PostingID": 4256, "Title": "LILLY-FID-US-HGJB", "Description": "A Controlled Trial of Olanzapine Versus Quetiapine in the Treatment of Schizophrenic and Schizoaffective Subjects with Prominent Negative Symptoms" },{ "PostingID": 4257, "Title": "LILLY-F1D-US-HGJU", "Description": "A Controlled Trial of Olanzapine Versus Ziprasidone in the Treatment of Schizophrenic and Schizoaffective Subjects with Comorbid Depression" },{ "PostingID": 4258, "Title": "LILLY-F1D-MC-HGHJ", "Description": "Olanzapine Versus Ziprasidone in the Treatment of Schizophrenia" },{ "PostingID": 4259, "Title": "LILLY-F1D-SN-S010", "Description": "Quality of Life in Asian Patients with Schizophrenia: Comparing Olanzapine with Haloperidol" },{ "PostingID": 5076, "Title": "LILLY-F1D-EW-LOBS", "Description": "Pharmacokinetic Characterization of Intramuscular Olanzapine Depot as a
Function of Particle Size Distribution" },{ "PostingID": 14571, "Title": "LILLY-F1D-MC-HGLQ", "Description": "A Randomized, Open-label Study Comparing the Effects of Olanzapine Pamoate Depot With Oral Olanzapine on Treatment Outcomes in Outpatients With Schizophrenia" },{ "PostingID": 16048, "Title": "SUNOVION-D1050229", "Description": "A Phase 3 Randomized, Placebo-Controlled, Clinical Trial to Study the Safety and Efficacy of Three Doses of Lurasidone HCl in Acutely Psychotic Patients With Schizophrenia" },{ "PostingID": 16049, "Title": "SUNOVION-D1050229E", "Description": "A Phase 3 Randomized, Placebo-Controlled, Clinical Trial to Study the Safety and Efficacy of Three Doses of Lurasidone HCl in Acutely Psychotic Patients With Schizophrenia (6-month Open-Label Extension)" },{ "PostingID": 16050, "Title": "SUNOVION-D1050231", "Description": "A Phase 3 Randomized, Placebo-and Active Comparator Controlled, Clinical Trial to Study the Safety and Efficacy of Two Doses of Lurasidone HCl in Acutely Psychotic Patients With Schizophrenia" },{ "PostingID": 16051, "Title": "SUNOVION-D1050231E", "Description": "A Phase 3 Randomized, Placebo-and Active Comparator Controlled, Clinical Trial to Study the Safety and Efficacy of Two Doses of Lurasidone HCl in Acutely Psychotic Patients With Schizophrenia (6-month Open-Label Extension)" },{ "PostingID": 16052, "Title": "SUNOVION-D1050233", "Description": "A Phase 3 Randomized, Double-Blind, Placebo- and Active Comparator-Controlled Clinical Trial to Study the Efficacy and Safety of Two Doses of Lurasidone in Acutely Psychotic Subjects With Schizophrenia (PEARL 3)" },{ "PostingID": 16053, "Title": "SUNOVION-D1050234", "Description": "A Phase 3 Randomized, Double-Blind, Active Comparator-Controlled Clinical Trial to Study the Safety and Efficacy of Lurasidone in Subjects With Schizophrenia (PEARL 3 Extension Study)" },{ "PostingID": 16055, "Title": "SUNOVION-D1050238", "Description": "A Double-Blind, Placebo-Controlled, Randomized Withdrawal Study Of Lurasidone For The Maintenance Treatment Of Subjects With Schizophrenia" },{ "PostingID": 17516, "Title": "LILLY-F1D-MC-HGAJ", "Description": "Olanzapine Versus Haloperidol in the Treatment of Schizophrenia and Other Psychotic Disorders" },{ "PostingID": 17517, "Title": "LILLY-F1D-MC-HGAP", "Description": "Fixed-Dose Olanzapine Versus Placebo in the Treatment of Schizophrenia" },{ "PostingID": 17518, "Title": "LILLY-F1D-MC-HGBG", "Description": "Olanzapine Versus Risperidone in the Treatment of Schizophrenia and Other Psychotic Disorders" },{ "PostingID": 17519, "Title": "LILLY-F1D-EW-HGCF", "Description": "Olanzapine Versus Clozapine in Refractory Schizophrenic Patients" },{ "PostingID": 17520, "Title": "LILLY-F1D-MC-HGCJ", "Description": "A Variable Dose Ranging Safety and Efficacy Study Comparing Olanzapine and Haloperidol in the Treatment of Patients with Schizophrenia" },{ "PostingID": 17521, "Title": "LILLY-F1D-MC-HGCU", "Description": "A Variable Dose Ranging Safety and Efficacy Study Comparing Olanzapine and Haloperidol in the Treatment of Patients with Schizophrenia" },{ "PostingID": 17522, "Title": "LILLY-F1D-MC-HGDY", "Description": "Study of Olanzapine in Schizophrenic Patients Discontinuing Clozapine Therapy" },{ "PostingID": 17523, "Title": "LILLY-F1D-MC-HGFT", "Description": "Fluoxetine Augmentation in Schizophrenic or Schizoaffective Patients with Depressive or Negative Symptoms Who Are Partial or Nonresponders to Olanzapine" },{ "PostingID": 19524, "Title": "LILLY-F1D-MC-HGFW", "Description": "Strategies for Switching from Conventional Antipsychotic Drugs to Olanzapine" },{ "PostingID": 19525, "Title": "LILLY-F1D-US-HGGD", "Description": "Cost-Effectiveness and Functional Outcomes of Olanzapine in the Treatment of Schizophrenia in Usual Clinical Practice: A Randomized Clinical Study" },{ "PostingID": 19526, "Title": "LILLY-F1D-US-HGHH", "Description": "Olanzapine in the Reduction of Hyperprolactinemia and Associated Morbidity in Schizophrenic Patients" },{ "PostingID": 19527, "Title": "LILLY-F1D-US-HGHO", "Description": "The Efficacy of Olanzapine and Adjunctive Lorazepam, as Needed, to Treat Acute Behavorial Agitation in Schizophrenia" },{ "PostingID": 19528, "Title": "LILLY-F1D-US-HGHR", "Description": "Olanzapine for the Treatment of Tardive Dyskinesia in Schizophrenic Patients" },{ "PostingID": 19529, "Title": "LILLY-F1D-US-HGIA", "Description": "Efficacy of Zyprexa Zydis® in the Treatment of Acutely Ill Non-Compliant Schizophrenic Subjects" },{ "PostingID": 19530, "Title": "LILLY-F1D-US-HGIY", "Description": "A Controlled Trial of the Efficacy of Rapid Initial Dose Escalation of Olanzapine to Treat Acute Behavioral Agitation in Schizophrenia and Bipolar I Disorder" },{ "PostingID": 19580, "Title": "GSK-223412/093", "Description": "A Multicenter, Double-Blind, Double-Dummy, Placebo-Controlled, Randomized, Parallel Group Evaluation of the Efficacy and Safety of a Fixed-Dose of Talnetant Versus Placebo Versus Risperidone in Subjects with Schizophrenia" },{ "PostingID": 19581, "Title": "GSK-NAA104606", "Description": "A Multi Centre, Double-Blind, Double-Dummy, Placebo-Controlled, Randomised, Adaptive, Dose-Range Study To Evaluate the Safety and Efficacy of SB-773812 Administered Once Daily for 12 Weeks in Adults With Schizophrenia" }]