Confusion Assessment Method

The Confusion Assessment Method (CAM) is a clinical tool that allows clinicians who are not trained in psychology to detect delirium in medical patients. Delirium often accompanies other health conditions and can result in complications that prevent the patient from making a full recovery. In the 2020s, more than 7 million hospitalized patients are affected by delirium each year in the United States alone. The use of CAM can result in significant reductions in delirium-related fatalities and complications, the length of hospitalizations, and medical costs.

Background

Delirium is severe confusion that comes on suddenly, often as a result of a physical or mental illness. As per the Diagnostic and Statistical Manual of Mental Disorders, fifth edition, text revision (DSM-5-TR), it is a disturbance in attention and awareness could be unclear. It happens when something affects the level of oxygen received by the brain. Infections, fevers, electrolyte imbalances, dehydration, poisons, overdoses of alcohol or drugs (including those used for anesthesia), and severe sleep deprivation can all reduce oxygen and often induce delirium. People with delirium usually cannot think or speak in an organized manner. They may be unable to remember where they are or why they are there and often have difficulty paying attention to what is happening around them.

While it is often temporary, delirium is associated with an increase in conditions that can cause health complications and hasten death. These include dementia, lack of mental function, decreased ability to live independently, and a greater risk of early death. Delirium most commonly affects older adults who are hospitalized for other conditions. However, some of its symptoms, such as fatigue or sleepiness and confusion, can be mistaken for symptoms of the patient’s primary illness or dismissed as a normal effect of being sedated for a surgical procedure.

Overview

CAM was developed in the late 1980s by medical doctor Sharon K. Inouye and her colleagues. They recognized that the presence of delirium was missed up to 70 percent of the time, even though its early detection and treatment improved the odds that a patient would have fewer complications. Inouye and the others developed an assessment tool for non-psychiatrically trained clinicians to identify patients experiencing delirium.

The assessment tool consists of a simple list of questions about the caregiver’s observations about the patient’s condition. The questions address the patient’s ability to think, pay attention, and remember. They assess the extent to which the patient’s ability to perform these actions is affected and whether this has changed during the assessment or from previous assessments. It also addresses whether the patient stares blankly or can focus on the caregiver and exhibits physical signs of mental agitation, such as tapping fingers or tossing about in place.

CAM enables the caregiver to identify the sudden onset of inattention, impaired thinking, or reduced level of consciousness that are the hallmarks of delirium. The caregiver can then alert the patient’s medical team to initiate treatment. The assessment provides an easy and effective way to identify potential problems and initiate a plan to prevent complications resulting from delirium.

Several variations of the CAM have been developed—the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) for assessing critically ill patients; the CAM Delirium Severity Scoring (CAM-S) for assessing the intensity of a patient’s delirium; and the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM) for assessing delirium quickly in high-risk situations. Despite its widespread use, some studies indicate that medical professionals lack proper training in using the CAM and its variations.

Bibliography

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“Delirium.” American Psychiatric Association, 2022, www.psychiatry.org/File%20Library/Psychiatrists/Practice/DSM/DSM-5-TR/APA-DSM5TR-Delirium.pdf. Accessed 24 Mar. 2026.

“Delirium Screening Tool: Confusion Assessment Method (CAM).” Alberta Health Services/Covenant Health, www.albertahealthservices.ca/assets/about/scn/ahs-scn-bjh-hf-delirium-screening-tool.pdf. Accessed 24 Mar. 2026.

Garcia Morales, Emmanuel E., et al. “Additional Hospitalization Costs Associated with Delirium among Older Adults: Evidence from the Medicare Current Beneficiary Survey.” Frontiers in Public Health, vol. 14, Jan. 2026, doi:10.3389/fpubh.2026.1750969. Accessed 7 Feb. 2026.

Inouye, Sharon K., et al. “Clarifying Confusion: The Confusion Assessment Method. A New Method for Detection of Delirium.” Annals of Internal Medicine, vol. 113, no. 12, 1990, pp. 941–48, doi:10.7326/0003-4819-113-12-941. Accessed 9 Mar. 2025.

Inouye, Sharon K. “The Confusion Assessment Method (CAM): Training Manual and Coding Guide.” The American Delirium Society, Oct. 2019, americandeliriumsociety.org/wp-content/uploads/2021/08/CAM-Long_Training-Manual.pdf. Accessed 24 Mar. 2026.

Inouye, Sharon K. “The Relationship between Delirium and Dementia.” Next Avenue, 14 Dec. 2018, www.nextavenue.org/relationship-delirium-dementia. Accessed 24 Mar. 2026.

McCabe, Donna. “The Confusion Assessment Method (CAM).” Try This: Best Practices in Nursing Care to Older Adults, Veterans Affairs, 2019, www.va.gov/covidtraining/docs/The_Confusion_Assessment_Method.pdf. Accessed 24 Mar. 2026.

Waszynski, Christine M. “Confusion Assessment Method (CAM).” Medscape, 2004, www.medscape.com/viewarticle/481726. Accessed 24 Mar. 2026.