Clinical Psychometrics

Clinical Psychometrics is an introduction to the long–term attempt to measure the psychiatric dimension of dementia, schizophrenia, mania, depression, anxiety, neuroticism, extraversion/introversion and health–related quality of life. The two psychometric procedures, classical factor analysis and modern item–response models, are presented for readers without any requirement for particular mathematical or statistical knowledge. The book is unique in this attempt and provides helpful background information for the dimensional approach that is being used in the forthcoming updates to the diagnostic classification systems, ICD–11 and DSM–5. The book is written for everyone who is interested in the origins and development of modern psychiatry, and who wants to be familiar with its practical possibilities; how it is possible to compare different individuals with each other, how one may determine the boundary between what is normal and what is disease, or how one may assess the clinical effect of the various forms of treatment, available to present day psychiatry.

About the author, ix Preface, x Introduction, 1 1. Classical psychometrics, 3 Emil Kraepelin: Symptom check list and pharmacopsychology, 6 Charles Spearman: Factor analysis and intelligence tests, 10 Harold Hotelling: Principal Component Analysis, 13 Hans Eysenck: Factor analysis and personality questionnaires, 15 Max Hamilton: Factor analysis and rating scales, 20 Pierre Pichot: Symptom rating scales and clinical validity, 23 2. Modern psychiatry: DSM–IV/ICD–10, 27 Focusing on reliability, 27 Focusing on validity, 28 Quantitative, dimensional diagnosis, 29 3. Modern dimensional psychometrics, 32 Ronald A. Fisher: From Galton’s pioneer work to the suffi cient statistic, 32 Georg Rasch: From Guttman’s pioneer work to item response theory analysis (IRT), 34 Sidney Siegel: Non–parametric statistics, 38 Robert J. Mokken: Non–parametric analysis for item response theory (IRT), 39 4. Modern psychometrics: Item categories and sufficient statistics, 43 Rensis Likert: Scale step measurements, 43 John Overall: Brief, sufficient rating scales, 45 Clinical versus psychometric validity, 48 Item–response theory versus factor analysis, 49 Jacob Cohen: Effect size, 50 5. The clinical consequence of IRT analyses: The pharmacopsychometric triangle, 53 Effect size and clinical significance, 53 The pharmacopsychometric triangle, 56 Antidementia medication, 59 Antipsychotic medication, 60 Antimanic medication, 65 Antidepressive medication, 66 Antianxiety medication, 69 Mood stabilising medications, 72 Combination of antidepressants, 73 6. The clinical consequence of IRT analyses: Health–related quality of life, 74 The WHO–5 Questionnaire, 78 7. The clinical consequences of IRT analyses: The concept of stress, 82 Post–traumatic stress disorder, 82 The work–related stress condition, 84 Integration of Selye’s medical stress model, 85 8. Questionnaires as ‘blood tests’ , 89 Population studies in depression and anxiety, 89 The predictive validity of WHO–5, 92 Screening scales, 92 9. Summary and perspectives, 95 10. Epilogue: Who’s carrying Einstein’s baton?, 103 Glossary, 109 Appendices, 114 References, 185 Index, 196

"...with his book clinical psychometrics, Dr. Bech is able to provide us with this easy understandable, philosophical and historical well outlined short book that gives the clinician an idea of the backgrounds of psychometrics and its relative application to – and implication for – psychiatry." ( Asian Journal of Psychiatry, 2013 ) "In a thoughtful way, Per Bech takes a thoughtful stance on the use of rating scales in daily psychiatric practice. Clinical Psychometrics should be a ‘must read’ for psychiatrists (in training) with interest in the clinical, mathematical and philosophical underpinnings of evidence–based psychiatry. For some readers, it will be a pleasurable self–limiting ‘Aha–Erlebnis’. For some readers, it will be the start of a different, more psychometric approach in diagnosis and treatment. For some readers, it could be the beginning of a further quest or participation in the aforementioned relay race, which cannot be run without clinically experienced psychiatrists." ( Acta Neuropsychiatrica, 2013 ) "Clinical Psychometrics represents a highly relevant contribution to the psychiatric field. It is well written, kept in a sound and plain medical language and enriched by an appendix containing the rating scales discussed in the text. I strongly recommend this book to all healthcare professionals with an interest in the measurement of psychological phenomena." Read the full review here . [ Acta Psychiatrica Scandinavica, 2012 ]