CGI: Clinical Global Impression. Rate global severity (S) based on the total clinical picture, and improvement (I) relative to baseline.
CGI-S: Severity
CGI-I: Improvement
Guidelines & Evidence
Clinical Details
Section 1
When to Use
Clinical Utility
Global assessment of psychiatric illness severity and treatment response
Universal outcome measure across all psychiatric diagnoses
Standardized reporting for cross-study comparisons and meta-analyses
Monitoring clinically significant change in routine psychiatric practice
Section 2
Formula & Logic
CGI-S (Severity)
Rated 1 (Normal, not at all ill) to 7 (Among the most extremely ill patients). Based on the clinician's experience with the specific patient population.
CGI-I (Improvement)
Rated 1 (Very much improved) to 7 (Very much worse). Measures change relative to the baseline state at the start of treatment.
Interpretation
CGI-I: 1 or 2
Treatment Responder
CGI-I: 4
No Change
CGI-I: 5, 6, or 7
Worsening / Non-Responder
Section 3
Evidence Appraisal
Validation
ECDEU Assessment Manual for Psychopharmacology.
Guy W. • US Department of Health, Education, and Welfare.. 1976;The original primary source for the Clinical Global Impressions scale.
What does the PANSS mean?
Leucht S et al. • Schizophr Res.. 2005;Provided robust anchoring of the CGI scale against domain-specific measures like the PANSS.
