The validity of the CGI severity and improvement scales as measures of clinical effectiveness suitable for routine clinical use

<b>Objective</b> The Clinical Global Impression Scale (CGI) is established as a core metric in psychiatric research. This study aims to test the validity of CGI as a clinical outcome measure suitable for routine use in a private inpatient setting.<br /><br /><b>Methods</b> The CGI was added to a standard battery of routine outcome measures in a private psychiatric hospital. Data were collected on consecutive admissions over a period of 24 months, which included clinical diagnosis, demographics, service utilization and four routine measures (CGI, HoNOS, MHQ-14 and DASS-21) at both admission and discharge. Descriptive and comparative data analyses were performed.<br /><br /><b>Results </b>Of 786 admissions in total, there were 624 and 614 CGI-S ratings completed at the point of admission and discharge, respectively, and 610 completed CGI-I ratings. The admission and discharge CGI-S scores were correlated (r = 0.40), and the indirect improvement measures obtained from their differences were highly correlated with the direct CGI-I scores (r = 0.71). The CGI results reflected similar trends seen in the other three outcome measures.<br /><br /><b>Conclusions </b>The CGI is a valid clinical outcome measure suitable for routine use in an inpatient setting. It offers a number of advantages, including its established utility in psychiatric research, sensitivity to change, quick and simple administration, utility across diagnostic groupings, and reliability in the hands of skilled clinicians.<br />