Ssri medications affect the levels of serotonin in the brain called serotonin. Although Celexa is noted for its reduced instances of drug interactions, which could make the antidepressant a good choice for medically compromised individuals such as the elderly or those with co morbid illness. Celexa helps to restore the brain's chemical balance by increasing the supply of a chemical messenger in the brain. Citalopram is primarily used to treat depression. Celexa is a selective serotonin reuptake inhibitors. Like any antidepressant, not everyone responds or tolerates any given medication. Celexa was shown to be effective in treating post-stroke depression and in alleviating emotional disturbances in elderly consumers with dementia disorders.