Re: Withdrawing from Mirtazapine
To be safe I would scale down any anti-depressant over a month at least, if not longer. Some people do get really bad withdrawal effects. If you consider that it takes a long time for your body to get used to the drug and for the drug to have a beneficial effect, it follows that it may take a long time for your body to adjust to the absence of the drug.
Mirtazapine has a half-life of 20-40 hours, so any tablet is in your body in a meaningful way for that period of time. By dropping the dose quickly and halving it, you really are reducing the amount of the drug in your blood. To lower from 15mg I'd suggest maybe trying to take 15mg on monday night, 7.5mg on Tuesday, 15mg on Wednesday, 7.5mg on Thursday and so on. I'd do that until I was sure I wasn't getting any bad side-effects. Then you could drop down to 7.5, 7.5, 7.5 etc.
I've heard of cases where people had to do that for months to come off Citalopram, but persevered and managed to get off it with no side effects. If you get bad side effects just resume your normal dose and start again with a less severe drop, even if it means shaving a 15mg tablet into quarters.