The long CAM: what it adds to the short form
Commentary. These are the author’s interpretations of the cited evidence. Disclosures.
The long CAM records a broader set of delirium features than the short form. Its extra ratings can help describe the symptoms a patient has. Both forms need an interview with cognitive testing.
What do people mean by “the CAM”?
When people say “the CAM”, they usually mean the short CAM: the four-feature diagnostic algorithm from the original 1990 study. The features concern acute onset or fluctuation, inattention, disorganised thinking and altered level of consciousness. These are clinical ratings. They are not four questions to ask a patient.
There is a small but useful historical distinction. The original paper described nine criteria, of which four contributed to the diagnostic algorithm (Inouye et al., 1990). The current long CAM has ten items, with psychomotor agitation and slowing rated separately. So the four-item short CAM should not be confused with the whole original instrument.
What does the long form add?
The long CAM retains the features used in the diagnostic algorithm and adds ratings of six other symptoms. Several ratings also record severity and fluctuation. The form allows the assessor to describe what they observed (Inouye, 2003, revised 2019).
| Form | What it records |
|---|---|
| Short CAM | The four diagnostic features: acute onset or fluctuation, inattention, disorganised thinking and altered level of consciousness. |
| Long CAM | The diagnostic features, plus disorientation, memory impairment, perceptual disturbances, psychomotor agitation, psychomotor slowing and altered sleep–wake cycle. |
The extra items broaden the description. They do not create a ten-item diagnostic total or replace the four-feature algorithm.
The assessment comes before the ratings
The long form asks for observations made during an interview and cognitive testing. That wording can be misunderstood. “Observations” includes how the patient responds during active assessment. It does not mean watching routine behaviour and then completing a checklist.
The manual also uses information about baseline cognition and recent change. Family members, staff and records can help establish this. Sleep–wake disturbance includes information from the preceding 24 hours. The supporting assessment therefore extends beyond the printed rating form (Inouye, 2003, revised 2019).
When is the extra detail useful?
The developer lists research and clinical uses for the long CAM (Delirium Central, n.d.). Its broader symptom coverage can help researchers describe delirium beyond a positive or negative classification. It may also help clinicians document features that need attention, such as perceptual disturbance or marked changes in activity.
The value depends on the question being asked. More recorded features do not, by themselves, establish better detection. If a study uses the long CAM as its reference assessment, readers need to know how the interview, cognitive tests, history and ratings were obtained. The form’s name alone cannot establish the quality or independence of that assessment.
Long CAM and CAM-S are different things
CAM-S is a separate system for scoring delirium severity from CAM feature ratings. It has a short form scored from 0 to 7 and a long form scored from 0 to 19. The long CAM can provide the underlying ratings for long-form CAM-S. Recording the long CAM is not the same as calculating a CAM-S severity score (Inouye et al., 2014).
“Short CAM” names the diagnostic form. “CAM-S” names the severity system. A paper or clinical record should state which one it uses.
My practical view
The long CAM has a clear role when a fuller account of delirium symptoms is needed. It requires training and the supporting assessment, just as the short CAM does. Its length does not make it a substitute for clinical judgement, investigation of causes or a response to the patient’s needs.
The concern about CAM used without cognitive testing applies to an altered procedure. It should not be transferred indiscriminately to either form when properly administered. Equally, a service cannot assume that it is following the validated method because its record contains a field labelled CAM.
Forms and training
The American Delirium Society provides the long CAM form, manual, training videos and answer keys. It also has a separate page for the short CAM. Use the form with its manual and check the current permission conditions.
See the CAM profile, short CAM profile and CAM-S severity profile for their evidence and other resources.
References
Delirium Central (n.d.) Delirium instruments: short CAM, long CAM and CAM-S. Accessed 5 September 2026.
Inouye, S.K. (2003, revised October 2019) The Confusion Assessment Method (CAM): Training Manual and Coding Guide. Boston: Hospital Elder Life Program. Public copy hosted by the American Delirium Society.
Inouye, S.K., van Dyck, C.H., Alessi, C.A. et al. (1990) Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Annals of Internal Medicine, 113, pp. 941–948.
Inouye, S.K., Kosar, C.M., Tommet, D. et al. (2014) The CAM-S: development and validation of a new scoring system for delirium severity in 2 cohorts. Annals of Internal Medicine, 160, pp. 526–533.