The use of weights to account for non-response and drop-out

Background: Empirical studies in psychiatric research and other fields often show substantially high refusal and drop-out rates. Non-participation and drop-out may introduce a bias whose magnitude depends on how strongly its determinants are related to the respective parameter of interest. Methods: When most information is missing, the standard approach is to estimate each respondent’s probability of participating and assign each respondent a weight that is inversely proportional to this probability. This paper contains a review of the major ideas and principles regarding the computation of statistical weights and the analysis of weighted data. Results: A short software review for weighted data is provided and the use of statistical weights is illustrated through data from the EDSP (Early Developmental Stages of Psychopathology) Study. The results show that disregarding different sampling and response probabilities can have a major impact on estimated odds ratios. Conclusions: The benefit of using statistical weights in reducing sampling bias should be balanced against increased variances in the weighted parameter estimates

Computergesteuerte Sprachwiedergabe in der experimentellen Umfrageforschung

'Der Beitrag berichtet über die Verwendung computergesteuerter Sprachwiedergabe in der experimentellen Umfrageforschung. In einer Studie zum Verständnis und zur Verständlichkeit standardisierter Interviewfragen bei älteren Personen werden Interviewfragen über einen PC akustisch dargeboten, und die Antworten wurden von den Befragten über einen berührungsempfindlichen Bildschirm eingegeben. Am Beispiel dieser Studie werden die Funktionsweise und Einsatzmöglichkeiten computergesteuerter Sprachwiedergabe dargestellt. Die verwendete Konfiguration ermöglicht eine 'intelligente', d. h. dynamische und bedingungsabhängige Interaktion mit den befragten Personen und weist eine hohe Äquivalenz zu face-to-face-Interviews auf.' (Autorenreferat)'The paper reports about the use of computerized speech presentation in experimental survey research. Survey questions are presented by PC to examine the comprehension and comprehensibility of standardized interview questions in the elderly. Using this study as an example, functions and advantages of computerized speech presentation are discussed. The reported configuration facilitates an 'intelligent', i. e. dynamic and conditional interaction with the respondents and offers high equivalence to face-to-face interviews.' (author's abstract)

Parental alcohol use disorders and alcohol use and disorders in offspring: a community study

Background. We examined the association between parental alcohol use disorders and patterns of alcohol consumption and DSM-IV alcohol use disorders in their offspring in a community-based sample of young adults. Methods. Data are based on baseline and 4-year follow-up data of 2427 respondents aged 14–24 at baseline. Alcohol use and disorders in respondents were assessed using the Munich-Composite-International-Diagnostic-Interview with DSM-IV algorithms. Diagnostic information about parents was collected by family history information from the respondents, and by direct interview with one parent (cohort aged 14 to 17 years only). Results. Although the association between maternal and paternal alcohol use disorders and non-problematical drinking in offspring was minimal, there was a strong effect for the transition to hazardous use and for alcohol abuse and dependence; the effect of parental concordance for transition into hazardous use was particularly striking. Maternal history was associated with a higher probability of progression from occasional to regular use, whereas paternal history was associated with progression from regular to hazardous use. Parental alcoholism increased the risk for first onset of hazardous use and alcohol dependence between the ages of 14–17, and for an earlier onset of the alcohol outcomes in offspring. The impact of parental alcohol use disorders was comparable for male and female offspring. Conclusions. Parental alcoholism predicts escalation of alcohol use, development of alcohol use disorders and onset of alcohol outcomes in offspring

Physical activity and prevalence and incidence of mental disorders in adolescents and young adults

ABSTRACT Background Although positive effects of physical activity on mental health indicators have been reported, the relationship between physical activity and the development of specific mental disorders is unclear. Method A cross-sectional (12-month) and prospective-longitudinal epidemiological study over 4 years in a community cohort of 2548 individuals, aged 14-24 years at outset of the study. Physical activity and mental disorders were assessed by the DSM-IV Composite International Diagnostic Interview (CIDI) with an embedded physical activity module. Multiple logistic regression analyses controlling for age, gender and educational status were used to determine the cross-sectional and prospective associations of mental disorders and physical activity. Results Cross-sectionally, regular physical activity was associated with a decreased prevalence of any and co-morbid mental disorder, due to lower rates of substance use disorders, anxiety disorders and dysthymia. Prospectively, subjects with regular physical activity had a substantially lower overall incidence of any and co-morbid mental disorder, and also a lower incidence of anxiety, somatoform and dysthymic disorder. By contrast, the incidence of bipolar disorder was increased among those with regular physical activity at baseline. In terms of the population attributable fraction (PAF), the potential for preventive effects of physical activity was considerably higher for men than for women. Conclusions Regular physical activity is associated with a substantially reduced risk for some, but not all, mental disorders and also seems to reduce the degree of co-morbidity. Further examination of the evidently complex mechanisms and pathways underlying these associations might reveal promising new research targets and procedures for targeted preventio

Care Strategies for Schizophrenic Patients in a Transcultural Comparison

This study was conducted in order to test the hypothesis derived from the International Pilot Study of Schizophrenia (IPSS) that the existence of extended families in developing countries contributes to the more favorable course and outcome of schizophrenia in these countries in comparison with industrial countries. For this purpose, we compared data from the 5- and 10-year follow-up obtained within the IPSS at Cali, Colombia with data from two 5 to 8-year follow-up studies of former schizophrenic inpatients of the Max Planck Institute of Psychiatry (MPIP) in Munich, FRG. Although, in Cali, schizophrenics are hospitalized and treated with drugs only during acute episodes of the psychosis and no facilities exist for long-term treatment, the psychopathological outcome was, on the whole, not worse than in Munich. Furthermore, the duration of hospitalization during the follow-up period was much lower at Cali and a significantly lower number of Colombian than of German patients was not separated from their families. However, contrary to the hypothesis, family size did not predict course and outcome at both centers

Psychopathological Profiles in Transsexuals and the Challenge of Their Special Status among the Sexes

OBJECTIVE:Investigating psychopathological profiles of transsexuals raises a very basic methodological question: are control groups, which represent the biological or the phenotypic sex, most suited for an optimal evaluation of psychopathology of transsexuals? METHOD:Male-to-female (MtF) (n=52) and female-to-male transsexuals (FtM) (n=32), receiving cross-sex hormone treatment, were compared with age matched healthy subjects of the same genetic sex (n=178) and with the same phenotypic sex (n=178) by means of the Symptom Check List-90-Revisited instrument (SCL-90-R). We performed analyses of covariance (ANCOVA) to test for group and sex effects. Furthermore, we used a profile analysis to determine if psychopathological symptom profiles of transsexuals more closely resemble genotypic sex or phenotypic sex controls. RESULTS:Transsexual patients reported more symptoms of psychopathological distress than did healthy control subjects in all subscales of the SCL-90-R (all p<0.001), regardless of whether they were compared with phenotype or genotype matched controls. Depressive symptoms were more pronounced in MtF than in FtM (SCL-90-R score 0.85 vs. 0.45, p = 0.001). We could demonstrate that FtM primarily reflect the psychopathological profile of biological males rather than that of biological females (r = 0.945), while MtF showed a slightly higher profile similarity with biological females than with biological males (r = 0.698 vs. r = 0.685). CONCLUSION:Our findings suggest that phenotypic sex matched controls are potentially more appropriate for comparison with the psychopathology of transsexual patients than are genetic sex matched controls

Prävalenz von Alkoholkonsum, Alkoholmißbrauch und -abhängigkeit bei Jugendlichen und jungen Erwachsenen

Alkoholkonsum beginnt häufig bereits im Jugendalter. Allerdings fehlen bisher Erkenntnisse darüber, ob, wie häufig und aufgrund welcher Merkmale Jugendlichen und junge Erwachsene auch bereits klinisch definierte Mißbrauchs- und Abhängigkeitsdiagnosen entwickeln. In der vorliegenden Arbeit werden Ergebnisse einer repräsentativen Untersuchung an 3021 Jugendlichen im Alter von 14-24 Jahren vorgestellt. Neben der Prävalenz von Alkoholmißbrauch und -abhängigkeit nach DSM-IV werden Daten zur Häufigkeit und Menge des Alkoholkonsums berichtet sowie erste Symptome beschrieben. 9,7% der befragten Jugendlichen erhielten aufgrund von DSM-IV-Kriterien eine Mißbrauchsdiagnose, 6,2% eine Abhängigkeitsdiagnose. Bei männlichen Jugendlichen war die Prävalenz wesentlich höher als bei weiblichen. Die Prävalenz war in den älteren Geburtskohorten höher. Als erstes Missbrauchssymptom trat am häufigsten "Gebrauch mit körperlicher Gefährdung" (91,9%), als erstes Abhängigkeitssymptom "Toleranzentwicklung" (34,3%) auf. Erste diagnostische Kriterien einer Alkoholstörung traten zumeist deutlich vor dem 18. Lebensjahr auf. Diese Daten unterstreichen, daß Alkoholmißbrauch und -abhängigkeit bereits im Jugend- und frühen Erwachsenenalter häufig sind.Alcohol use frequently begins in adolescence. However, only few studies have reported the prevalence of alcohol abuse disorders in adolescents. This paper reports results from a representative study in a sample of 3021 adolescents, aged 14-24 years. The Prevalence of alcohol abuse and dependence according to DSM-IV criteria, as well as the prevalence, frequency and quantity of alcohol abuse and a description of the first occuring symptoms, are presented here. Alcohol abuse was reported by 9.7% of respondents and alcohol dependence by 6.2%. Males were more likely to report an alcohol disorder than females, and the prevalence also increased in the older age cohorts. The most frequent initial symptoms were "hazardous use" (91.9%) for abuse and "tolerance" (34.3%) for dependence. First symptoms have been shown to occur long before the age of 18. These results show that even in adolescents and young adults alcohol abuse and dependence are frequent disorders

Tabakentwöhnungsmaßnahmen in der allgemeinärztlichen Versorgung: Implementierung, Effektivität und Wege einer optimierten Allokation

Hintergrund / Ziel der Studie: Im Bereich der Tabakentwöhnung existieren mittlerweile zahlreiche erprobte therapeutische Maßnahmen und Medikamente. Dennoch ist die Inanspruchnahme vorhandener Entwöhnungsangebote sehr dürftig. Es besteht die begründete Hoffnung, dass durch eine stärkere Einbeziehung der Hausärzte in den Bereich der Tabakentwöhnung eine Versorgungslücke geschlossen werden könnte. Die Studie soll Durchführbarkeit und Erfolg einer solchen Ausweitung des Anbieterkreises von Tabakentwöhnungsmaßnahmen im Hausarztbereich untersuchen. Unterschiedliche bereits vorhandene Therapieansätze werden hierbei hinsichtlich Effektivität und Effizienz in der allgemeinärztlichen Routineversorgung miteinander verglichen. Methoden: In Phase I der Studie werden bundesweit Patienten in mehr als 800 Arztpraxen an einem Stichtag per Fragebogen zu ihrer Gesundheit und ihrem Rauchverhalten befragt. In Phase II werden die in Phase I identifizierten entwöhnungswilligen Raucher in ausgewählten Arztpraxen für die Intervention rekrutiert und randomisiert vier Gruppen mit (idealerweise) jeweils 250 Personen zugeteilt: einer Bupropion SR (Zyban®)-Gruppe, einer Nikotinersatzmittel-Gruppe, einer Verhaltenstherapie-Gruppe und einer Kontrollgruppe. Die Behandlung erfolgt jeweils durch die Ärzte in ihren Praxen unter Supervision und mit Unterstützung durch Studienmonitore. Erwartete Ergebnisse: In Abhängigkeit von Merkmalen des Arztes und seiner Praxis auf der einen Seite sowie Merkmalen der betroffenen Patienten auf der anderen, sollte die Akzeptanz, Durchführbarkeit und Wirksamkeit der ausgewählten Therapieansätze unterschiedlich ausfallen. Insgesamt sollte jedoch jede Therapiebedingung gegenüber der Kontrollbedingung hinsichtlich ihrer Effektivität überlegen sein. Im 6-Monats Follow-up sollte die Zyban-Gruppe gegenüber allen anderen Gruppen die höchste Abstinenzquote aufweisen. Schlussfolgerung: Die Ergebnisse sollten Hinweise auf Möglichkeiten einer bedarfsgerechten, optimierten Allokation vorhandener Maßnahmen zur Tabakentwöhnung in der allgemeinärztlichen Versorgung liefern.Background / aim of the study: Although a number of efficacious smoking cessation measures and medications do exist, only a small number of smokers (tobacco users) make use of them. A stronger engagement of general practitioners (GPs) in the field of smoking cessation might help to improve health care in this important area. The study will investigate feasibility and effectiveness of different readily available smoking cessation measures under routine conditions in primary health care practices. Method: In phase I of the study patients' health status and tobacco consumption are assessed by means of questionnaires provided on a nationwide appointed date in more than 800 general practices in Germany. In phase II selected practices offer smoking cessation treatments to identified smokers. Participants recruited will be randomly assigned to four groups ideally consisting of 250 subjects each: A bupropion SR (Zyban©) condition, a nicotine replacement therapy (NRT) group, a cognitive-behavioural treatment (CBT) group and a control condition. Treatments will be conducted by GPs in their practices under supervision of study monitors offering therapeutical and organisational support. Expected results: Acceptance, feasibility, and effectiveness of smoking cessation treatments offered will differ depending on GP and patient characteristics. Overall, success-rates (while success is primarily defined as abstinence from tobacco use) should be higher in all therapeutic conditions as compared to controls. In the 6-month follow-up abstinence rates are expected to be highest in the bupropion SR group. Conclusion: Results should yield indications for an improved allocation of available smoking cessation measures in primary care

Refined Estimation of Earthquake Source Parameters: Methods, Applications and Scaling Relationships

The objective of this work of thesis is the refined estimations of source parameters. To such a purpose we used two different approaches, one in the frequency domain and the other in the time domain. In frequency domain, we analyzed the P- and S-wave displacement spectra to estimate spectral parameters, that is corner frequencies and low frequency spectral amplitudes. We used a parametric modeling approach which is combined with a multi-step, non-linear inversion strategy and includes the correction for attenuation and site effects. The iterative multi-step procedure was applied to about 700 microearthquakes in the moment range 1011-1014 N•m and recorded at the dense, wide-dynamic range, seismic networks operating in Southern Apennines (Italy). The analysis of the source parameters is often complicated when we are not able to model the propagation accurately. In this case the empirical Green function approach is a very useful tool to study the seismic source properties. In fact the Empirical Green Functions (EGFs) consent to represent the contribution of propagation and site effects to signal without using approximate velocity models. An EGF is a recorded three-component set of time-histories of a small earthquake whose source mechanism and propagation path are similar to those of the master event. Thus, in time domain, the deconvolution method of Vallée (2004) was applied to calculate the source time functions (RSTFs) and to accurately estimate source size and rupture velocity. This technique was applied to 1) large event, that is Mw=6.3 2009 L’Aquila mainshock (Central Italy), 2) moderate events, that is cluster of earthquakes of 2009 L’Aquila sequence with moment magnitude ranging between 3 and 5.6, 3) small event, i.e. Mw=2.9 Laviano mainshock (Southern Italy)

Structure, Content and Reliability of the Munich-Composite International Diagnostic Interview (M-CIDI) Substance Use Sections

After reviewing currently available diagnostic assessment instruments for substance use disorders this paper describes the format and structure of the Munich-Composite International Diagnostic Interview (M-CIDI) substance disorder section. In addition, the test-retest reliability of diagnoses and criteria for nicotine, alcohol, illegal and prescription drugs, is reported. Findings obtained in community sample of adolescents and young adults indicate that the substance section is acceptable for almost all types of respondents, efficient in terms of time and ease of administration as well as reliable in terms of consistency of findings over time. The test-retest reliability over a period of an average of 1 month, as examined by two independent interviewers indicates good-to-excellent kappa values for all substance disorders assessed, with significant kappa values ranging between 0.55 for drug abuse and 0.83 for alcohol abuse. There was also fairly consistently high agreement for the assessment of single DSM-IV diagnostic criteria for abuse and dependence as well as the M-CIDI quantity-frequency and time-related questions. To conclude, although – unlike previous studies – this study was conducted in a community sample and not in patients and used considerably longer time intervals of more than a month between investigations, our M-CIDI reliability findings are at least as high as those from previous studies