Translation and validation of a German version of the “Hopkins Competency Assessment Test,” a brief method for evaluating patients’ capacity to give consent

Abstract Background The “Hopkins Competency Assessment Test” (HCAT) assesses a patient’s ability to provide written informed consent or advance directives. It includes an essay for three reading difficulty levels (12th, 8th, and 6th school grade) and an understanding questionnaire. Currently, there is no equivalent test to the HCAT in German. Therefore, we translated, adapted, and evaluated a German version of the HCAT. Methods We conducted a cross-sectional study to evaluate the psychometric properties of the HCAT in a clinical and a non-clinical sample. Statistical analysis included ANOVA and t-tests for group comparisons. Cronbach’s alpha was used to assess internal consistency; an exploratory factor analysis (EFA) was conducted to examine the underlying factor structure; and network analysis with centrality indices to explore the relational structure among HCAT items and to identify particularly central components within the network. The data collection and analysis were approved (BASEC 2021-01123) by the ethics committee of the Canton of Zurich. Results We enrolled two samples: one clinical, consisting of 110 psychiatric inpatients, and for comparison, one non-clinical, consisting of 32 participants recruited from hospital staff. We present the results from both samples, unless stated otherwise. The total number of participants, both clinical and non-clinical, was 142 individuals; the majority were male (n = 117, 82.4%), with a mean age of 37.5 years. Most had no education beyond regular school (n = 69, 48.6%). Among the psychiatric patients, schizophrenia (n = 87, 75.5%) was the primary diagnosis, followed by affective disorders (24.5%). Patients often had comorbid substance use disorders (n = 39, 35.5%). A considerable proportion completed the HCAT successfully in the first attempt (n = 100, 70.4%) or the second attempt (n = 20, 14.1%). All participants of the non-clinical sample completed the HCAT successfully on the first attempt. For those requiring more than one attempt, the Intraclass Correlation Coefficient between the different HCAT reading difficulty versions was 0.07 (F(19,6.81) = 1.75, p = .23). The essay took 2.0 (0.8) minutes to read and 5.3 (3.1) minutes to answer. Persons in psychiatric treatment required more time, more attempts, and had lower scores. The Cronbach’s alpha was 0.88. The CFA suggested a two-factor model as the preferred solution. In our interpretation, the network analysis revealed the dynamics influencing consent capacity and highlighted the role of risk-benefit valuation for patients (or potential participants) in informed decision-making. Conclusion The German version of the HCAT demonstrated promising psychometric properties and may be a useful tool for screening for decisional capacity in psychiatric patients.