A 39-year-old woman with difficult-to-treat depression has tried all the antidepressant classes except MAOIs. She is currently taking an SSRI that will require a 5-week washout period before switching to an MAOI. Which of the following SSRIs is she currently taking?

Choice A reason: Escitalopram has a relatively short half-life and typically requires a 2-week washout period before initiating an MAOI to avoid serotonin syndrome. Choice B reason: Sertraline also has a shorter half-life and does not require a 5-week washout. A 2-week period is generally sufficient. Choice C reason: Fluoxetine has the longest half-life among SSRIs, with active metabolites that persist in the body for weeks. Due to this extended duration, a 5-week washout period is recommended before starting an MAOI to prevent serotonin toxicity. Choice D reason: Paroxetine has a short half-life and would not necessitate a 5-week washout. A 2-week interval is typically adequate.