ABSTRACT
Drug-induced dementia is the most common reversible dementia. It is difficult to
determine the prevalence for a variety of reasons: (i) Drug-induced dementia and
delirium are most common in patients with pre-existing, underlying dementia. In
identifying this co-morbid state is difficult in routine clinical practice. (ii) It is
difficult to assess compliance with medications, especially when patients (parti-
cularly those with pre-existing cognitive impairments) are receiving a large
number of prescription and nonprescription medications, as a result, it is hard
to assign causality to medications. (iii) All dementias are routinely underde-
tected. Most studies suggest that drug-induced cognitive impairment as a source
of co-morbidity is common. In primary care medicine this may occur in as many
as 10-15% of all dementias. The two commonest manifestations of drug-induced
cognitive impairments are delirium and dementia.
