hi. im not trying to question your psychiatrist, but...
using -any- antipsychotic, no matter how 'atypical,' when someone lacks motivation, is lethargic, feels emotionally numb, and has cognitive issues strikes me as a bit...counter-productive. these drugs are being pushed -hard- as safe, non-addictive add ons, etc., but...if my main problem was that sort of depression, id personally steer clear of antipsychotics and most ssri drugs (prozac can be less apathy-inducing than some others).