A client with major depressive disorder has been taking fluoxetine an SSRI for 5 weeks. During the first outpatient visit the client smiles and states "I feel like a great weight is off my chest." How should the nurse interpret this behavior change?

The correct answer is A because it indicates a positive response to fluoxetine, an SSRI, typically seen after 4-6 weeks of treatment for major depressive disorder. The client expressing relief and improved mood is a good sign of the medication's efficacy. Choice B is incorrect as the client's statement does not suggest suicidal planning; it reflects improvement. Choice C is incorrect because there is no indication for decreasing the dosage or adding a mood stabilizer based on the client's positive response. Choice D is incorrect as serotonin syndrome is not suggested by the client's statement.