Abstract
The therapeutic relationship plays a crucial role in nursing care for people with mental illness. Adopting a systemic and person-centred approach that considers the individual experiences and needs of the person is paramount. However, no instruments were found in the literature designed to evaluate the nurse-patient therapeutic relationship from the perspective of a person with mental illness. This study aimed to develop and evaluate the psychometric properties of an instrument for assessing the quality of the nurse-patient therapeutic relationship from the patient's perspective. An e-Delphi study was conducted to develop the assessment tool, and a psychometric study was carried out to examine its psychometric properties. The sample comprised 240 adults with mental illness. Internal consistency was assessed using Cronbach's alpha and the Omega coefficient. The final structure of the assessment instrument included 24 items distributed across two factors, explaining 64.2% of the variance. Cronbach's alpha was 0.94, and the Omega coefficient was 0.96. The intraclass correlation coefficient was 0.84 (95% CI: 0.66-0.92). The therapeutic relationship assessment scale (TRAS-Patient) shows good psychometric properties. This is a relevant tool for assessing the quality of the nurse-patient therapeutic relationship from the patient's perspective, thus promoting a patient-centred approach and responding to the patient's needs. Mental health nurses can access a tool for evaluating the nurse-patient therapeutic relationship centred on disciplinary knowledge. This enables patient involvement in care, enhanced care and person-centred practice.