"i have been taking low dose mirtazapine (3.75 mgs) for about 10 wks now for anxiety, insomnia and mild depression. i was prescribed this after being unable to tolerate ssri anti depressants and having a very bad reaction to lexapro. mirtazapine has worked well for insomnia and i started noticing improvements in anxiety levels and mood within 3-4 wks of starting.  i initially had a mild increase in appetite but no weight gain, and my appetite is now normal. the drawback to this med is daytime fatigue/groggy sensation that does not lift until late afternoon. i was told this would improve with time, but it has not. for this reason i will likely taper off the med soon - not something i can put up with long term despite being effective for insomnia/anxiety."