The regression discontinuity design showed to be a valid alternative to a randomized controlled trial for estimating treatment effects.

OBJECTIVES: To compare treatment effect estimates obtained from a regression discontinuity (RD) design with results from an actual randomized controlled trial (RCT). STUDY DESIGN AND SETTING: Data from an RCT (EVIDENT), which studied the effect of an Internet intervention on depressive symptoms measured with the Patient Health Questionnaire (PHQ-9), were used to perform an RD analysis, in which treatment allocation was determined by a cutoff value at baseline (PHQ-9 = 10). A linear regression model was fitted to the data, selecting participants above the cutoff who had received the intervention (n = 317) and control participants below the cutoff (n = 187). Outcome was PHQ-9 sum score 12 weeks after baseline. Robustness of the effect estimate was studied; the estimate was compared with the RCT treatment effect. RESULTS: The final regression model showed a regression coefficient of -2.29 [95% confidence interval (CI): -3.72 to -.85] compared with a treatment effect found in the RCT of -1.57 (95% CI: -2.07 to -1.07). CONCLUSION: Although the estimates obtained from two designs are not equal, their confidence intervals overlap, suggesting that an RD design can be a valid alternative for RCTs. This finding is particularly important for situations where an RCT may not be feasible or ethical as is often the case in clinical research settings.

Evaluation of a computer-adaptive test for the assessment of depression (D-CAT) in clinical application.

In the past, a German Computerized Adaptive Test, based on Item Response Theory (IRT), was developed for purposes of assessing the construct depression [Computer-adaptive test for depression (D-CAT)]. This study aims at testing the feasibility and validity of the real computer-adaptive application.The D-CAT, supplied by a bank of 64 items, was administered on personal digital assistants (PDAs) to 423 consecutive patients suffering from psychosomatic and other medical conditions (78 with depression). Items were adaptively administered until a predetermined reliability (r > or = 0.90) was attained. For validation purposes, the Hospital Anxiety and Depression Scale (HADS), the Centre for Epidemiological Studies Depression (CES-D) scale, and the Beck Depression Inventory (BDI) were administered. Another sample of 114 patients was evaluated using standardized diagnostic interviews [Composite International Diagnostic Interview (CIDI)].The D-CAT was quickly completed (mean 74 seconds), well accepted by the patients and reliable after an average administration of only six items. In 95% of the cases, 10 items or less were needed for a reliable score estimate. Correlations between the D-CAT and the HADS, CES-D, and BDI ranged between r = 0.68 and r = 0.77. The D-CAT distinguished between diagnostic groups as well as established questionnaires do.The D-CAT proved an efficient, well accepted and reliable tool. Discriminative power was comparable to other depression measures, whereby the CAT is shorter and more precise. Item usage raises questions of balancing the item selection for content in the future.

An evaluation of patient-reported outcomes found computerized adaptive testing was efficient in assessing stress perception.

OBJECTIVES: This study aimed to develop and evaluate a first computerized adaptive test (CAT) for the measurement of stress perception (Stress-CAT), in terms of the two dimensions: exposure to stress and stress reaction. STUDY DESIGN AND SETTING: Item response theory modeling was performed using a two-parameter model (Generalized Partial Credit Model). The evaluation of the Stress-CAT comprised a simulation study and real clinical application. A total of 1,092 psychosomatic patients (N1) were studied. Two hundred simulees (N2) were generated for a simulated response data set. Then the Stress-CAT was given to n=116 inpatients, (N3) together with established stress questionnaires as validity criteria. RESULTS: The final banks included n=38 stress exposure items and n=31 stress reaction items. In the first simulation study, CAT scores could be estimated with a high measurement precision (SE<0.32; rho>0.90) using 7.0+/-2.3 (M+/-SD) stress reaction items and 11.6+/-1.7 stress exposure items. The second simulation study reanalyzed real patients data (N1) and showed an average use of items of 5.6+/-2.1 for the dimension stress reaction and 10.0+/-4.9 for the dimension stress exposure. Convergent validity showed significantly high correlations. CONCLUSIONS: The Stress-CAT is short and precise, potentially lowering the response burden of patients in clinical decision making.

Functioning and validity of a Computerized Adaptive Test to measure anxiety (A-CAT).

BACKGROUND: The aim of this study was to evaluate the Computerized Adaptive Test to measure anxiety (A-CAT), a patient-reported outcome questionnaire that uses computerized adaptive testing to measure anxiety. METHODS: The A-CAT builds on an item bank of 50 items that has been built using conventional item analyses and item response theory analyses. The A-CAT was administered on Personal Digital Assistants to n=357 patients diagnosed and treated at the department of Psychosomatic Medicine and Psychotherapy, Charité Berlin, Germany. For validation purposes, two subgroups of patients (n=110 and 125) answered the A-CAT along with established anxiety and depression questionnaires. RESULTS: The A-CAT was fast to complete (on average in 2 min, 38 s) and a precise item response theory based CAT score (reliability>.9) could be estimated after 4-41 items. On average, the CAT displayed 6 items (SD=4.2). Convergent validity of the A-CAT was supported by correlations to existing tools (Hospital Anxiety and Depression Scale-A, Beck Anxiety Inventory, Berliner Stimmungs-Fragebogen A/D, and State Trait Anxiety Inventory: r=.56-.66); discriminant validity between diagnostic groups was higher for the A-CAT than for other anxiety measures. CONCLUSIONS: The German A-CAT is an efficient, reliable, and valid tool for assessing anxiety in patients suffering from anxiety disorders and other conditions with significant potential for initial assessment and long-term treatment monitoring. Future research directions are to explore content balancing of the item selection algorithm of the CAT, to norm the tool to a healthy sample, and to develop practical cutoff scores.

Development and evaluation of a computer adaptive test for 'Anxiety' (Anxiety-CAT).

Within the framework of item response theory (IRT), we developed a German version of an item bank, as well as a software application that can be employed to measure anxiety by means of a computer adaptive test (CAT). A sample of n = 2348 psychiatric and psychosomatic patients answered a set of up to 13 standardized questionnaires. 81 items drawn from these questionnaires were considered pertinent to the anxiety construct. Various tests were conducted to ensure the suitability of these items for an IRT-based assessment. After these tests, 50 items remained in the item bank and were calibrated using the Generalized Partial Credit Model. Simulation studies conducted on an independent sample of n = 1528 respondents indicate that 6-8 items suffice to measure the latent trait with high precision (standard error

Three assessment tools for deliberate self-harm and suicide behavior: evaluation and psychopathological correlates.

OBJECTIVE: The aims of this study are to adapt two validated self-report questionnaires of deliberate self-harm and suicidal behavior to German, to investigate their psychometric properties and agreement with clinician-administered ratings, and to examine their psychopathological correlates. METHODS: The Deliberate Self-Harm Inventory [Gratz KL. Measurement of deliberate self-harm: preliminary data on the deliberate self-harm inventory. J Psychopathol Behav 2001;23:253-263] and the Self-Harm Behavior Questionnaire [Guttierez PM, Osman A, Barrios FX, Kopper BA. Development and initial validation of the self-harm behavior questionnaire. J Pers Assess 2001;77:475-490] were completed by 361 patients hospitalized for depressive, anxiety, adjustment, somatoform, and/or eating disorders. A clinician-administered rating scale of self-destructive behavior was included. Psychopathological variables were assessed by standardized questionnaires. RESULTS: The self-report questionnaires demonstrated good reliability (alpha=.81-.96, split-half r=.78-.98, test-retest r=.65-.91). Reliability of the clinician-administered ratings was acceptable (interrater kappa=.46-.77, test-retest kappa=.35-.48). Intraclass correlations (ICC=.68) for all three instruments were satisfactory. Rates of self-harm and associations between self-harm and suicidal behaviors are reported. The findings support the hypotheses of a higher degree of psychiatric symptomatology in patients with self-harm behavior compared to those without. CONCLUSION: The two questionnaire adaptations are reliable and valid self-report scales for the assessment of self-harm and past suicidal behavior.

[Standardized diagnosing: computer-assisted (CIDI) diagnoses compared to clinically-judged diagnoses in a psychosomatic setting]. / Standardisierte Diagnosefindung: Computergestützte (CIDI)--versus klinische Diagnosestellungen an einer psychosomatischen Stichprobe.

BACKGROUND: Within the past two decades, there has been an increasing trend towards the use of empirically-based, standardized instruments to diagnose mental disorders. The purpose of this study was to investigate the congruence between clinically-derived and standardized computerized diagnoses using the Composite International Diagnostic Interview (CIDI) in a psychosomatic setting. PATIENTS AND METHODS: N = 230 inpatients treated at the Department of Psychosomatic Medicine, Charité Berlin, were diagnosed for mental disorders by experienced clinicians and by the CIDI according to the diagnostic criteria of ICD-10 and DSM-IV. RESULTS: Congruence between computerized and clinically-derived diagnoses for all mental disorders was fair to poor (kappa = 0.0 - 0.33). The diagnostic congruence of somatoform (F45), anxiety (F40 - 41), depressive (F32 - 34), eating (F50) and dissociative disorders (F44) and disorders due to psychoactive substance use (F10 - 19) was fairly low (kappa = 0.19 - 0.33). Diagnostic congruence of diagnoses of reactions to severe stress (F43) and obsessive compulsive disorders (F42) was particularly poor (kappa = 0.0 - 0.01). CONCLUSION: Overall diagnostic congruence between computerized and clinical diagnostics was unsatisfactory. Thus, the validity of computer-assisted standardized interviews - like the CIDI - is questionable in a psychosomatic setting.

Development of a computer-adaptive test for depression (D-CAT).

Depression is one of the most prevalent mental health problems and measuring depressive symptoms becomes increasingly important in science as well as medical practice. Computer Adaptive Tests (CAT) based on the Item Response Theory (IRT) promise to enhance measurement precision and reduce respondent's burden. Our aim was to develop a CAT application to measure depressive symptoms. Three thousand two hundred seventy psychosomatic patients answered an overall of 11 mental health questionnaires at the University Clinic in Berlin. Three independent reviewers rated 144 items out of these questionnaires as indicative of depressive symptoms. All items underwent six empirical steps to analyze unidimensionality, local independence and item discrimination. Finally 64 items could be used to calculate item parameters applying a Generalized Partial Credit Model (GPCM). CAT scores were estimated using an 'expected a posteriori' algorithm (EAP). Two simulation experiments showed that for theta values within the range of 2SD around the mean (98% of the cases), the latent trait can be estimated out of approximately six items with a predefined standard error of [Symbol: see text] 0.32 (reliability rho [Symbol: see text] 0.90). The CAT-scores correlated high with scores of all depression items (r = 0.95), with the Beck Depression Inventory (r = 0.79) and with a CES-D 8 item short form (r = 0.76). We conclude that the Depression-CAT measures depressive symptoms with high precision and low respondent burden.

The Perceived Stress Questionnaire (PSQ) reconsidered: validation and reference values from different clinical and healthy adult samples.

OBJECTIVE: The aim was to translate, revise, and standardize the Perceived Stress Questionnaire (PSQ) by Levenstein et al. (1993) in German. The instrument assesses subjectively experienced stress independent of a specific and objective occasion. METHODS: Exploratory factor analyses and a revision of the scale content were carried out on a sample of 650 subjects (Psychosomatic Medicine patients, women after delivery, women after miscarriage, and students). Confirmatory analyses and examination of structural stability across subgroups were carried out on a second sample of 1,808 subjects (psychosomatic, tinnitus, inflammatory bowel disease patients, pregnant women, healthy adults) using linear structural equation modeling and multisample analyses. External validation included immunological measures in women who had suffered a miscarriage. RESULTS: Four factors (worries, tension, joy, demands) emerged, with 5 items each, as compared with the 30 items of the original PSQ. The factor structure was confirmed on the second sample. Multisample analyses yielded a fair structural stability across groups. Reliability values were satisfactory. Findings suggest that three scales represent internal stress reactions, whereas the scale "demands" relates to perceived external stressors. Significant and meaningful differences between groups indicate differential validity. A higher degree of certain immunological imbalances after miscarriage (presumably linked to pregnancy loss) was found in those women who had a higher stress score. Sensitivity to change was demonstrated in two different treatment samples. CONCLUSION: We propose the revised PSQ as a valid and economic tool for stress research. The overall score permits comparison with results from earlier studies using the original instrument.

[Personality and donor-recipient relationships of potential donors before living donor liver transplantation--diagnostics with the repertory-grid technique]. / Selbst-Empfänger-Beziehungen bei potenziellen Spendern vor Leberlebendspende--Eine Diagnostik mit der Repertory-Grid-Technik.

BACKGROUND: Living-donor liver transplantation (LDLT) is developing into an established therapy for terminal liver diseases in adults. Potential donors are faced with the risk of postoperative complications and are subject to a high level of psychological pressure and ambivalent feelings. Our assumption is that ambivalent feelings before donation are crucially influenced by the personality and the quality of the donor-recipient relationship. In highly motivated donors we expected a positive description of the recipient and a similarity in the characterisation of the donor and recipient. METHODS: 58 potential living donors were evaluated between March 2000 and June 2001. On the basis of the clinical interview 10 were rated as unsuited for donation. Among those potential donors assessed as unsuited, we found a high level of ambivalent feelings. For 50 potential donors we gained a set of completed psychometric diagnostic questionnaires. A Repertory-grid investigation was conducted with a total of 28 potential donors. Seven of them were not recommended as living donors. The relationship between donors and recipients was analysed concerning constructs that were most important to the characterisation of the donor or recipient. By means of inter-element distances self-concept of donors and donor-recipient relation were analysed. RESULTS: Ambivalent candidates who were not recommended as living donors tended to describe the recipient negatively (selfish, carping, and unable to take criticism) and did not show a similarity in the characterisations of self and ideal-self. Whereas the highly motivated candidates were marked by a closeness of self and ideal-self concepts. Both groups saw the recipient as indifferent. CONCLUSION: Closeness between self and ideal-self-indicating satisfaction with the decision to donate seems to be one suitable criterion to distinguish between highly motivated potential donors on the one hand and ambivalent candidates on the other hand. Another criterion appears to be a description of the recipient that indicates either a functioning or ill-functioning communication between donor and recipient with respect to the donation.