I stopped feeling benefits of Sertraline after 10 good years & my psychiatrist added 7.5mg Mirtazapine. Started to sleep well, even felt less anxious & depressed, after 10 days started to feel bad again, so he upped dose to 15mg. Within 2 days felt much better, but now feelng a bit anxious again. Is this likely to continue until it really gets into my system? Feeling myself again and then waking up feeling anxious & depressed. Very disappointed but I'll carry on regardless!