Clinical Global Impression Scale (CGI): Measuring Severity

The Clinical Global Impression Scale (CGI) is a key tool for tracking mental health progress. It helps clinicians measure how well treatments work. This brief observer-rated scale stands out because it is simple and fast. It captures a patient's global functioning before and after starting medication or therapy. The CGI uses two main subscales. The Severity of Illness scale rates symptoms from one to seven, and the Global Improvement scale tracks changes from baseline. Scores range from very much improved to very much worse, offering a clear view of clinical change. Clinicians value this tool because it takes only a few minutes to finish. It is useful in clinical trials to see if a new drug is effective. By comparing scores over time, healthcare teams can make better decisions about continuing or changing a care plan. It helps ensure patients get the right support.