A patient diagnosed with major depressive disorder began taking citalopram (Celexa) 4 days ago. The patient now says, "This medicine isn't working." The nurse's best intervention would be to:

Explain the time lag before antidepressants relieve symptoms.

Discuss with the health care provider the need to increase the dose.

Critically assess the patient for symptoms of improvement.

Reassure the patient that the medication will be effective soon.