Clinical global impression

Clinical Global Impression (CGI) is a scale used by mental health professionals to rate the severity of a patient's illness, change over time, and efficacy of treatments. It is a widely used tool in clinical research and practice for assessing treatment outcomes in psychiatric and psychological disorders. The CGI is divided into three parts: Severity of Illness (CGI-S), Global Improvement (CGI-I), and Efficacy Index.

CGI-S: Severity of Illness

The CGI-S scale allows the clinician to rate the severity of the patient's illness at the time of assessment, relative to the clinician's past experience with patients who have the same diagnosis. The scale is as follows:

• 0: Not assessed
• 1: Normal, not at all ill
• 2: Borderline mentally ill
• 3: Mildly ill
• 4: Moderately ill
• 5: Markedly ill
• 6: Severely ill
• 7: Among the most extremely ill patients

CGI-I: Global Improvement

This scale measures the patient's improvement or worsening relative to a baseline state at the beginning of the intervention. The CGI-I is rated as follows:

• 0: Not assessed
• 1: Very much improved
• 2: Much improved
• 3: Minimally improved
• 4: No change
• 5: Minimally worse
• 6: Much worse
• 7: Very much worse

Efficacy Index

The Efficacy Index is calculated by considering both the therapeutic effect and the treatment side effects. It is a ratio where the numerator is the CGI-I score and the denominator is the side effect rating, allowing for a balanced assessment of the treatment's overall efficacy.

Application

The CGI is applied across a wide range of psychiatric and psychological disorders, including Depression, Anxiety Disorders, Schizophrenia, and many others. It is valued for its simplicity, ease of use, and applicability to all psychiatric disorders, making it a versatile tool in both research and clinical settings.

Limitations

Despite its widespread use, the CGI has some limitations. Its subjective nature can lead to variability between raters. Additionally, the CGI does not provide a detailed analysis of specific symptoms or symptom clusters, which can be important in understanding the nuances of a patient's condition or response to treatment.

Conclusion

The Clinical Global Impression scale is a fundamental tool in the assessment of treatment outcomes in psychiatric and psychological disorders. Its simplicity and versatility make it a valuable resource for clinicians and researchers alike. However, its subjective nature and lack of specificity highlight the importance of using it in conjunction with other, more detailed assessment tools.