The Confusion Assessment Method (CAM) assesses for the presence of delirium and was created specifically for clinicians without psychiatric training to use with older patients. It was designed for use in both clinical and research settings, such as in making observations during routine clinical care.
Since its development in 1988-1990, it has become the most widely used instrument for detection of delirium worldwide, because of both its strong validation results as well as its ease of use. It has been used either a process or outcome measure, and has been translated into more than 6 languages.
The CAM is usually rated by a clinical or trained lay interviewer on the basis of an interview with the patient that includes at least a brief cognitive assessment. Generally, the entire CAM rating takes 5-10 minutes to complete.
Concurrent validation with psychiatric diagnosis revealed sensitivity of 94-100% and specificity of 90-95%. The CAM significantly correlated with the Mini-Mental Status Examination, the Visual Analog Scale for Confusion, and the digit span test.
There is a false positive rate of 10%; and it identifies the presence or absence of delirium but does not assess the severity of the condition
, making it less useful to detect clinical improvement or deterioration.
Inouye SK, vanDyck CH, Alessi CA, Balkin S, Siegal AP, Horwitz RI. Clarifying confusion: the Confusion Assessment Method. A new method for detection of delirium. Ann Intern Med. 1990; 113: 941-948.