Le rappel onirique : fiabilité, malléabilité et relation au contexte sociocognitif

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Analyse de validité de la déclaration (SVA), mensonge et faux souvenirs : validité et efficacité chez les adultes

Le SVA est utilisé pour évaluer la crédibilité d'un témoignage, surtout dans des cas d'abus sexuels. Les buts de cette étude étaient d'en évaluer l'efficacité et de vérifier si les effets observés étaient dus à l'intention de tromper ou à la source du souvenir (interne vs externe). 34 participantes racontèrent 2 événements ou 2 rêves (1 réel et 1 inventé) après 2 jours ou plus de préparation. Seize des 19 critères du SVA furent évalués. Les récits réels contenaient plus d'incohérences et moins de détails inusités que les récits inventés. Aucun autre critère du SVA ne fut efficace. Les effets étaient causés exclusivement par l'intention de tromper. Les résultats indiquent qu'en contexte de variabilité et préparation réaliste, le SVA perd son efficacité

Assessment of the psychosocial predictors of health-related quality of life in a PTSD clinical sample

Although a wide array of the scientific literature explores the links between posttraumatic stress disorder (PTSD) symptoms, coping strategies, and social support and health-related quality of life (HRQoL) as an outcome variable, their connections remain unclear. It is unknown whether PTSD symptom severity, coping strategies, and social support explain each a unique portion of variance of HRQoL of individuals with PTSD. In the current study, based on pretreatment results of a broader study assessing a specific intervention for PTSD, 94 individuals with PTSD were screened for psychiatric disorders and completed several questionnaires concerning social support, coping strategies, PTSD symptoms, and HRQoL. Coping strategies, social support, and PTSD all appeared to be predictors of HRQoL; however, PTSD seemed to constitute the major predictor among these variables. Indeed, coping strategies and social support did not explain a unique share of variability of HRQoL beyond that of PTSD symptomatology. A causal pathway integrating these variables should be tested in future studies

Nightmare frequency, nightmare distress and the efficiency of trauma-focused cognitive behavioral therapy for post-traumatic stress disorder

Background: Up to 71% of trauma victims diagnosed with PTSD have frequent nightmares (NM), compared to only 2% to 5% of the general population. Objectives: The present study examined whether nightmares before the beginning of cognitive behavior therapy (CBT) for posttraumatic stress disorder (PTSD) could influence overall PTSD symptom reduction for 71 individuals with PTSD and different types of traumatic events. Patients and Methods: Participants received a validated CBT of 20 weekly individual sessions. They were evaluated at five measurement times: at pre-treatment, after the third and ninth session, at post-treatment, and at 6 months follow-up. Results: The presence of nightmares did not impact overall CBT efficiency. Specific CBT components were efficient in reducing the frequency and distress of nightmares. Conclusions: Most participants no longer had PTSD but some still had nightmares

Relative efficacy of cognitive-behavioral therapy administered by videoconference for posttraumatic stress disorder : a six-month follow-up

Until recently, only one study was published on cognitive-behavioral therapy (CBT) of posttraumatic stress disorder (PTSD) in individual therapy via videoconference (Germain, Marchand, Bouchard, Drouin, & Guay, 2009); however, it only assessed the posttreatment effect. This study presents the follow-up of Germain et al.’s (2009) study. The main goal was to compare the effectiveness after six months of CBT for PTSD either face-to-face (n = 24) or by videoconference (n = 12). Each participant received CBT for 16 to 25 weeks and completed various questionnaires before and after treatment and at a six-month follow-up. The two treatments had equivalent levels of symptom reduction (Modified PTSD Symptom Scale: η2 .05) and proportion of patients with a clinically significant change in symptoms (42% for face-to-face vs. 38% for videoconferencing, p > .05). Thus, CBT for PTSD via videoconference seems to be a viable alternative when adequate face-to-face treatments are less available

How do social interactions with a significant other affect PTSD symptoms? An empirical investigation with a clinical sample

Social support and coping are both related to posttraumatic stress disorder (PTSD) symptoms, but the mechanisms underlying their relationships remain unclear. This study explores these relationships by examining the perceived frequency of supportive and countersupportive interactions with a significant other in PTSD patients. Ninety-six participants with PTSD were recruited and completed questionnaires assessing social interactions, ways of coping, and PTSD symptoms. Associations of social interactions (r2 = 4.1%–7.9%, p < .05) and coping (r2 = 15.9%– 16.5%, p < .001) with symptoms were independent, and suggested a direct association between social interactions and PTSD. Countersupportive interactions were more associated to symptoms than supportive interactions. Our findings suggest the development of psychotherapies that integrate social support interventions

A life-course and time perspective on the construct validity of psychological distress in women and men. Measurement invariance of the K6 across gender

<p>Abstract</p> <p>Background</p> <p>Psychological distress is a widespread indicator of mental health and mental illness in research and clinical settings. A recurrent finding from epidemiological studies and population surveys is that women report a higher mean level and a higher prevalence of psychological distress than men. These differences may reflect, to some extent, cultural norms associated with the expression of distress in women and men. Assuming that these norms differ across age groups and that they evolve over time, one would expect gender differences in psychological distress to vary over the life-course and over time. The objective of this study was to investigate the construct validity of a psychological distress scale, the K6, across gender in different age groups and over a twelve-year period.</p> <p>Methods</p> <p>This study is based on data from the Canadian National Population Health Survey (C-NPHS). Psychological distress was assessed with the K6, a scale developed by Kessler and his colleagues. Data were examined through multi-group confirmatory factor analyses. Increasing levels of measurement and structural invariance across gender were assessed cross-sectionally with data from cycle 1 (n = 13019) of the C-NPHS and longitudinally with cycles 1 (1994-1995), 4 (2000-2001) and 7 (2006-2007).</p> <p>Results</p> <p>Higher levels of measurement and structural invariance across gender were reached only after the constraint of equivalence was relaxed for various parameters of a few items of the K6. Some items had a different pattern of gender non invariance across age groups and over the course of the study. Gender differences in the expression of psychological distress may vary over the lifespan and over a 12-year period without markedly affecting the construct validity of the K6.</p> <p>Conclusions</p> <p>This study confirms the cross-gender construct validity of psychological distress as assessed with the K6 despite differences in the expression of some symptoms in women and in men over the life-course and over time. Findings suggest that the higher mean level of psychological distress observed in women reflects a true difference in distress and is unlikely to be gender-biased. Gender differences in psychological distress are an important public health and clinical issue and further researches are needed to decipher the factors underlying these differences.</p

Confidence Intervals: From tests of statistical significance to confidence intervals, range hypotheses and substantial effects

For the last 50 years of research in quantitative social sciences, the empirical evaluation of scientific hypotheses has been based on the rejection or not of the null hypothesis. However, more than 300 articles demonstrated that this method was problematic. In summary, null hypothesis testing (NHT) is unfalsifiable, its results depend directly on sample size and the null hypothesis is both improbable and not plausible. Consequently, alternatives to NHT such as confidence intervals (CI) and measures of effect size are starting to be used in scientific publications. The purpose of this article is, first, to provide the conceptual tools necessary to implement an approach based on confidence intervals, and second, to briefly demonstrate why such an approach is an interesting alternative to an approach based on NHT. As demonstrated in the article, the proposed CI approach avoids most problems related to a NHT approach and can often improve the scientific and contextual relevance of the statistical interpretations by testing range hypotheses instead of a point hypothesis and by defining the minimal value of a substantial effect. The main advantage of such a CI approach is that it replaces the notion of statistical power by an easily interpretable three-value logic (probable presence of a substantial effect, probable absence of a substantial effect and probabilistic undetermination). The demonstration includes a complete example

Ganando confianza con intervalos: guías prácticas, consejos y trucos para enfrentar situaciones reales de investigación.

Confidence intervals and measures of effect size are gradually becoming the standard way of reporting the results of statistical analyses in research articles, used instead of or in addition to p values. However, this shift in research practices barely affected teaching practices up to now. This paper is the third of a series written to serve as a general reference on the use of confidence intervals in quantitative social sciences. Its purpose is to provide guidelines, advices and useful tricks of the trade that will allow readers (a) to face most of the statistical problems emerging in real-life research settings and (b) to improve their understanding of confidence intervals and answer more efficiently their questions of interest. The first part of the article briefly introduces the basic elements of an approach based on confidence intervals: Calculations, interpretation, and hypothesis testing. The second part is an attempt to present some of the most important (but sometimes neglected) advanced issues concerning confidence intervals: Graphic representations, complex distributions, national surveys, the larger family of interval statistics (e.g., prediction intervals), and the Bayesian approach to probabilities.Los intervalos de confianza (IC) y las medidas de tamaño de efecto están convirtiéndose gradualmente en la forma estándar de reportar resultados de análisis estadísticos en artículos de investigación, en lugar de, o además de, los valores p. Sin embargo, tal cambio en las prácticas de investigación se ha comunicado poco en la enseñanza de la estadística. Este artículo es el tercero en una serie escritos que sirven como referencia general sobre el use de los IC en las ciencias sociales. Este artículo tiene como propósito proveer guías, consejos, y trucos útiles que le permitan al lector (a) enfrentar la mayoría de problemas estadísticos que suceden en situaciones reales de investigación y (b) mejorar su conocimiento sobre los IC y contestar más eficientemente las preguntas de interés. La primera parte del artículo presenta brevemente los elementos básicos acerca del uso de los IC: cómo computarlos, cómo interpretarlos, y cómo usarlos en las pruebas de hipótesis.  La segunda parte presenta algunos de los asuntos más importantes (aunque algunas veces negados) acerca de los IC: representaciones gráficas, distribuciones complejas, encuestas nacionales, la familia de la estadística de los intervalos (e.g., intervalos de predicción), y la aproximación Bayesiana a las probabilidades