The development and validation of the SOLES, a new scale measuring engagement with mental health services in people with psychosis

Background: No reliable and well-validated patient-rated scale exists for measuring engagement with mental health services. Alliance scales are often used as a proxy measure and most are clinician-rated. Aim: This study aimed to develop and validate the SOLES (Singh O'Brien Level of Engagement Scale), designed to measure engagement in people with psychosis. Method: The SOLES was developed in focus groups and validated in patients with psychosis. Reliability was tested using Cronbach's alpha and split-half reliability. Factor analysis was conducted. Concurrent validity (correlating SOLES scores with measures of alliance, insight and satisfaction), discriminant validity and predictive validity (whether SOLES predicts drop-out) were tested. Results: As some subjects had no keyworker two scales were developed, for with and without a keyworker; the SOLES 16 and SOLES 13. Both have good internal consistency, correlate with relevant scales and scores predict engagement. Conclusions: The SOLES is reliable, valid and is a potentially valuable research and clinical tool.