"Coercion Experience Scale" (CES)--validation of a questionnaire on coercive measures.

Background: Although the authors of a Cochrane Review on seclusion and mechanical restraint concluded that "there is a surprising and shocking lack of published trials" on coercive interventions in psychiatry, there are only few instruments that can be applied in trials. Furthermore, as main outcome variable safety, psychopathological symptoms, and duration of an intervention cannot meet the demand to indicate subjective suffering and impact relevant to posttraumatic stress syndromes. An instrument used in controlled trials should assess the patients' subjective experiences, needs to be applicable to more than one intervention in order to compare different coercive measures and has to account for the specific psychiatric context.

Methods: The primary version of the questionnaire comprised 44 items, nine items on restrictions to human rights, developed on a clinical basis, and 35 items on stressors, derived from patients' comments during the pilot phase of the study. An exploratory factor analysis (EFA) using principal axis factoring (PAF) was carried out. The resulting factors were orthogonally rotated via VARIMAX procedure. Items with factor loadings less than .50 were eliminated. The reliability of the subscales was assessed by calculating Cronbach.

Results: Data of 102 patients was analysed. The analysis yielded six factors which were entitled "Humiliation", "Physical adverse effects", "Separation", "Negative environment", "Fear" and "Coercion". These six factors explained 54.5% of the total variance. Cronbach alpha ranged from .67 to .93, which can be interpreted as a high internal consistency. Convergent and discriminant validity yielded both highly significant results (r = .79, p < .001, resp. r = .38, p < .001).

Conclusions: The "Coercion Experience Scale" is an instrument to measure the psychological impact during psychiatric coercive interventions. Its psychometric properties showed satisfying reliability and validity. For purposes of research it can be used to compare different coercive interventions. In clinical practice it can be used as a screening instrument for patients who need support after coercive interventions to prevent consequences from traumatic experiences. Further research is needed to identify possible diagnostic, therapeutic or prognostic implications of the total score and the different subscales.

Trial Registration: Current Controlled Trials ISRCTN70589121.