Step 1: Decode the tool by its purpose. CAM is built around acute onset, fluctuating course, inattention, disorganized thinking and a changed level of consciousness, the exact hallmarks of an acute confusional state.
Step 2: That feature set maps onto delirium, an acute and reversible disturbance of attention and awareness, not a chronic cognitive decline.
Step 3: Separate it from the other choices by their own scales. Dementia uses MMSE or MoCA, depression uses PHQ-9 or Hamilton, and schizophrenia uses PANSS, so none of these is what CAM measures.
Step 4: The condition CAM is designed to identify is delirium.
\[\boxed{\text{Delirium}}\]