While dementia is progressive, other forms or causes of cognitive decline may be temporary, reversible or worsen no further. Conditions such as delirium, depression, sensory impairment (eg sight or hearing loss) or cognitive impairment from medicine, particularly those associated with increased anticholinergic burden, need to be considered before diagnosing dementia.¹

Delirium is a change in a person’s mental state or consciousness that develops over hours or days. It may appear as confusion, memory and understanding difficulties, or personality changes so may sometimes be mistaken for dementia. In addition to sudden confusion, a common delirium feature is the person becomes less responsive or alert to things happening around them.^14,15,16

Health professionals seeing the patient for the first time may have difficulties in distinguishing between delirium and dementia, so asking family, friends or carers for information on how behaviour has changed can be helpful.¹⁶

Sometimes delirium occurs alongside dementia (delirium superimposed on dementia). If determining whether the person has delirium, dementia or a combined presentation is not possible, initial treatment should target delirium.¹