My suggestions, not all to be taken seriously:
1) Make DF into the sims, and give all the dwarfs a Social metre that slowly falls. (Or make it emo dwarf fortress and replace the social metre with a angst metre that slowly fills up, making the dwarf cut himself every so often and play really depressing harp music.
2) Make a sanity stat that lowers when the dwarf is faced with a very overwhelming emotion or situation, such as having their whole family die, or getting chased by a fire demon. You could even have it like amnesia: the dark descent, in which having low sanity will result in shaking, heaving breathing, the occasional hallucination of bugs crawling on you, culminating in your character sliding is face along the ground, drooling and mumbling like an idiot.
3) Hallucinations, either good or bad. Good being imaginary friends to talk to. Bad being nightmares while awake, using your dwarfs dislike to find the perfect hallucination. May lead to the awkward realization that your miner has 30 friends when there are only 7 dwarfs, or that the dwarf has enjoyed a lengthy conversations about politics with his cat recently.
Perhaps there would be a religious equivalent to the hammerer that would exorcise dwarves (even for simple matters such as extreme depression or melancholy) if an appropriate psychiatrist was not at hand.
Exorcism via hammer? Dwarf priests don't mess around.