I do appreciate your concern for your parents. Dementia
is a disorder with multiple causes which leads to decline in memory and other cognitive functions. Celexa
which is a selective serotonin reuptake inhibitor. It is an anti-depressant and used for treatment of anxiety
and depressive disorders.
As of now, Citalopram has not shown to be effective in cases of dementia. However, if the memory and cognitive disturbance is due to depression
or anxiety (which is termed as pseudo-dementia), it responds of Citalopram or any other anti-depressant. You can discuss regarding the same with your physician.
Hope this information was helpful. Best wishes.