I'd avoid it. Mirtazepine is an antagonist at alpha2 adrenergic autoreceptors, like yohimbine is, as well as its more well known extraordinarily potent antihistaminic effect.
Awful shit too IMO, made me just about ready to have thrown myself off a bridge, had there been one to do it with, dreadful, dreadful akathisia. One of the worst experiences in my life. Right up there with the likes of benzo, barbiturate or GHB withdrawal in terms of foulness, although of of a different nature.
Moclobemide does seem to be somewhat forgiving. Infinitely more than the old noncompetitive MAOIs like the hydrazines, (not like a hydrazine moiety is a good sign in anything you might put in your mouth to be honest), a girl I know of on one of another forum I frequent takes (and has for long enough to be stable on the combination) moclobemide/dexamphetamine along with haldol and benztropine. Seems to like the combination, as it helps her well seemingly.
Although mixing moclobemide and dexphet would make me nervous as hell.