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Clinical Global Impression (CGI) Scales: Bold Medicine

The Clinical Global Impression (CGI) scales provide clinicians with a concise method to assess the severity of a patient's condition and track changes in their condition over time. The CGI uses two scales - the CGI-Severity scale measures illness severity at baseline, while the CGI-Improvement scale measures changes compared to baseline. Both use 7-point scales to characterize the patient's condition. The CGI scales have been shown to correlate with other assessment tools and are used in clinical trials to support drug approvals. An improvement of 0.5 on the CGI-I scale indicates a clinically significant change that influences treatment decisions. When administering the CGI scales, clinicians draw on all available information about the patient over the past week.

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252 views3 pages

Clinical Global Impression (CGI) Scales: Bold Medicine

The Clinical Global Impression (CGI) scales provide clinicians with a concise method to assess the severity of a patient's condition and track changes in their condition over time. The CGI uses two scales - the CGI-Severity scale measures illness severity at baseline, while the CGI-Improvement scale measures changes compared to baseline. Both use 7-point scales to characterize the patient's condition. The CGI scales have been shown to correlate with other assessment tools and are used in clinical trials to support drug approvals. An improvement of 0.5 on the CGI-I scale indicates a clinically significant change that influences treatment decisions. When administering the CGI scales, clinicians draw on all available information about the patient over the past week.

Uploaded by

natsumi18
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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BOLD MEDICINE:

Clinical Global
Impression (CGI)
Scales
CGI SCALES:

Clinically Assessing an Individual’s Global Functioning

Since the 1970s, Clinical Global Impressions (CGI) scales have been used in
clinical studies to provide objective clinical impressions of a single individual
that transcend mere symptom checklists.

The scales track clinical progress across time, taking into account all available information:

• Patient’s history • Symptoms

• Caregiver input • Behavior

• Psychosocial circumstances • Impact of the symptoms on the patient’s ability to function

CGI scales have been shown to correlate with other, longer rating clinical measurement tools across a wide range of neurologic

and psychiatric diagnoses. It has been used to support drug regulatory approvals for schizophrenia, bipolar disorder and ADHD

treatments.

Tracking Improvement Over Time with the Two CGI Scales

The methodology includes two companion one-item measures evaluating the following:

CGI-SEVERITY (CGI-S) CGI-IMPROVEMENT (CGI-I)

An objective measure of condition severity at the start of the An objective measure of a single patient’s change

trial, establishes a baseline for each patient (improvement or worsening) compared to baseline

Clinicians ask: “Considering your total clinical experience with Clinicians ask: “Compared to the patient’s condition at

this particular population, how ill is the patient at this time?” baseline, this patient’s [average] condition has…?”

Answers fall on the following seven-point scale: Answers fall on the following seven-point scale:

Normal, not at The most Very much Very much


all impaired severely impaired improved worse
What CGI Scores Mean

The two CGI scales help track changes that are relevant to each individual patient.

While the CGI-I score generally tracks with the CGI-S—in that
For the CGI-I scale specifically,
improvement in one follows improvement in the other—the

±.05
a change of 0.5 indicates a
clinical impact of significance two CGI scores can occasionally be dissociated. A clinician
that will influence a physician’s may notice changes in the CGI-I relative to baseline, despite
treatment decisions.
no recent change in the overall CGI-S score, or vice versa.

A Brief Guide to Administering CGI Scales

The general administration guidelines for CGI scales have evolved over the years, but some of the more commonly
used research conventions include:

The Administrator
In clinical research, the CGI is administered by an experienced clinician who is familiar with the disease under study
and the likely progression of treatment—who can make an expert clinical global judgment about illness severity
across time and within the context of that clinical experience.

The Assessment
The clinician makes a judgment about the total picture of the patient at each visit: the illness severity, the patient’s
level of distress and other aspects of impairment, and the impact of the illness on functioning. The CGI is rated
without regard to the clinician’s belief that any clinical changes are or are not due to medication and without
consideration of the etiology of the symptoms.

The Timeframe
The CGI is usually rated relative to the past seven days (including the day of the visit up to and through the visit). In
this respect, the CGI is a state-dependent measure summarizing one week rather than a lifetime of symptoms and
behavior.

The Sources of Information


Make use of all information available—a clinical patient interview should be combined with any other information
available for the time period under study, from such sources as chart notes, family members, caseworkers, unit
nurses, schoolteachers for children, or significant others.

The Questions to Ask


Establish the presence of relevant symptoms, the frequency of their occurrence over the seven-day rating
timeframe, the intensity or severity of the symptoms, and the effect of the symptoms on functioning in major areas
of the patient’s life: work, home, school, and relationships.

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