Das Basler Interview für Psychosen (BIP): Struktur, Reliabilität und Validität

Hintergrund: Obwohl in den letzten Jahren zahlreiche Instrumente entwickelt worden sind, um Psychoserisikopersonen und Psychoseersterkrankte zu identifizieren, gab es bisher keine geeigneten Instrumente, um solche Personen ausführlicher über ihren Krankheitsverlauf sowie die Risikofaktoren und frühen Indikatoren der Erkrankung zu befragen. Wir haben deshalb das Basler Interview für Psychosen (BIP) entwickelt. Ziel der vorliegenden Arbeit ist es, die Entwicklung und den Aufbau des BIP zu beschreiben sowie über seine psychometrischen Eigenschaften zu berichten. Methoden: Das BIP ist ein halbstrukturiertes klinisches Anamneseinterview, das im Rahmen des Basler Projekts zur Früherkennung von Psychosen (FePsy) auf der Basis der wichtigsten in der Literatur beschriebenen Risikofaktoren und Indikatoren für Psychosen und unter Berücksichtigung schon existierender Fragebögen entwickelt wurde. Es gliedert sich in sechs Bereiche: 1. Soziale und körperliche Entwicklung/Familie, 2. Anzeichen und Symptome, 3. Vulnerabilität, 4. Hilfesucheverhalten, 5. Krankheitseinsicht, 6. Interviewereinschätzung. Um die Interrater-Reliabilität der Items der Abschnitte 2 und 3 zu bestimmen, wurden 20 Patienten von insgesamt 8 unterschiedlichen Ratern beurteilt. Die faktorielle Struktur des Abschnitts 2.3 „Prodromi und Symptome“ wurde in einer Stichprobe von 120 Psychoserisikopersonen und 77 Erstpsychosepatienten untersucht. Auf der Basis der gefundenen Faktorstruktur wurden neue Skalen gebildet und auf ihre Reliabilität und Validität untersucht. Ergebnisse: Von 153 untersuchten Items der Abschnitte 2 und 3 wurden 150 (98 %) mit ausreichend hoher Übereinstimmung (Interrater-Reliabilität > 0,4) eingeschätzt. Die Items des Abschnitts 2.3 „Prodromi und Symptome“ konnten zu 5 Subskalen gruppiert werden. Die Subskalen wiesen überwiegend gute bis sehr gute interne Konsistenzen, Homogenitäten und diskriminante und konvergente Validitäten auf. Für die Subskalen „Positive psychotische Symptome“ und „Störungen des Denkens“ sowie den Gesamtscore konnte zudem eine prädiktive Validität nachgewiesen werden. Diskussion: Mit dem BIP haben wir erstmals ein halbstrukturiertes klinisches Anamneseinterview konstruiert und validiert, das geeignet ist, Psychoserisikopatienten und Psychoseersterkrankte detailliert über Psychoserisikofaktoren und -indikatoren sowie den psychopathologischen Verlauf seit der Kindheit zu befragen. Wir konnten zeigen, dass das BIP hervorragende psychometrische Eigenschaften aufweist. BACKGROUND: Although several instruments have been developed to identify patients with an at-risk mental state (ARMS) for psychosis and first episode of psychosis (FEP), up to now there were no instruments for a detailed assessment of risk factors and indicators of emerging psychosis and the temporal development of psychiatric symptoms over the whole life span in these patients. We therefore developed the Basle Interview for Psychosis (BIP). The aim of this study is to describe the development of the BIP and to report about its psychometric properties. METHODS: The BIP is a comprehensive semi-structured interview that was developed for the Basel early detection of psychoses (FePsy) study. Its items were derived from the most important risk factors and indicators of psychosis described in the literature and from several existing instruments. It contains the following six sections: 1) social and physical development and family, 2) signs and symptoms, 3) vulnerability, 4) help-seeking behavior, 5) illness insight, 6) evaluation of the interview. To estimate the inter-rater reliabilities of the items of sections 2 and 3, 20 interviews were conducted and rated by 8 well-trained raters. The factorial structure of the BIP section "signs and symptoms" was explored in a sample of 120 ARMS and 77 FEP patients. On the basis of the discovered factorial structure, we created new subscales and assessed their reliabilities and validities. RESULTS: Of the 153 studied items of sections 2 and 3, 150 (98 %) were rated with sufficiently high agreement (inter-rater reliability > 0.4). The items of section "signs and symptoms" could be grouped into 5 subscales with predominantly good to very good internal consistencies, homogeneities, and discriminant and convergent validities. Predictive validities could be demonstrated for the subscales "Positive Psychotic Symptoms", "Disturbance of Thinking" and the total score. DISCUSSION: The BIP is the first interview for comprehensively assessing risk factors and indicators of emerging psychosis and the temporal development of psychiatric symptoms over the whole life span, which has been validated in ARMS and FEP patients. We could show that the BIP has excellent psychometric properties

Versatile strategy for homogeneous drying patterns of dispersed particles

After spilling coffee, a tell-tale stain is left by the drying droplet. This universal phenomenon, known as the coffee ring effect, is observed independent of the dispersed material. However, for many technological processes such as coating techniques and ink-jet printing a uniform particle deposition is required and the coffee ring effect is a major drawback. Here, we present a simple and versatile strategy to achieve homogeneous drying patterns using surface-modified particle dispersions. High-molecular weight surface-active polymers that physisorb onto the particle surfaces provide enhanced steric stabilization and prevent accumulation and pinning at the droplet edge. In addition, in the absence of free polymer in the dispersion, the surface modification strongly enhances the particle adsorption to the air/liquid interface, where they experience a thermal Marangoni backflow towards the apex of the drop, leading to uniform particle deposition after drying. The method is independent of particle shape and applicable to a variety of commercial pigment particles and different dispersion media, demonstrating the practicality of this work for everyday processes

Probing sedimentation non-ideality of particulate systems using analytical centrifugation

Analytical centrifugation is a versatile technique for the quantitative characterization of colloidal systems including colloidal stability. The recent developments in data acquisition and evaluation allow the accurate determination of particle size, shape anisotropy and particle density. High precision analytical centrifugation is in particular suited for the study of particle interactions and concentration-dependent sedimentation coefficients. We present a holistic approach for the quantitative determination of sedimentation non-idealityviaanalytical centrifugation for polydisperse, plain and amino-functionalized silica particles spanning over one order of magnitude in particle size between 100 nm and 1200 nm. These systems typically behave as neutral hard spheres as predicted by auxiliary lattice Boltzmann simulations. The extent of electrostatic interactions and their impact on sedimentation non-ideality can be quantified by the repulsion range, which is the ratio of the Debye length and the average interparticle distance. Experimental access to the repulsion range is provided through conductivity measurements. With the experimental repulsion range at hand, we estimate the effect of polydispersity on concentration-dependent sedimentation properties through a combination of lattice Boltzmann and Brownian dynamics simulations. Finally, we determine the concentration-dependent sedimentation properties of charge-stabilized, fluorescently-labeled silica particles with a nominal particle size of 30 nm and reduced interparticle distance, hence an elevated repulsion range. Overall, our results demonstrate how the influence of hard-sphere type and electrostatic interactions can be quantified when probing sedimentation non-ideality of particulate systems using analytical centrifugation even for systems exhibiting moderate sample heterogeneity and complex interactions