Switching to another
antidepressant monotherapy offers a simpler regimen, while the
advantages of add-on therapy are potentially faster response, the
ability to address specific residual symptoms and/or side effects, a
perceived psychological advantage of “boosting” the effect of the
first agent, and the ability to allow a patient to continue longer
on the first agent in the event they are a late responder (Lam et
al., 2009).