There do seem to be levels, certainly.
So, in the third year of my current fort, a large group of migrants arrived to find miasma, blood spatter, rotting corpses, ghosts, a distinct lack of bedrooms, and a single dwarf frantically making coffins. The adults were immediately organized into military squads, and ordered to wear the best (mostly leather) equipment they could find. They quickly got the corpses laid to rest and started getting everything else put back in order.
Less than a month later, that lone survivor turned into a large lizard and started attacking anything that moved, killing a couple of the new migrants and injuring others before being put down. A month later, a couple of the injured turned into lizards, and so on. Fortunately, the transformations stopped after a few months, and migrants kept coming "despite the danger."
Life went on, but eventually one child started wandering around obliviously. I might've been more worried with a different fortress design, but the child was nowhere near any falling hazards, so I just watched her stumble around until she got thirsty. Not long afterward, she cancelled a job because she was too depressed. The tantrums started a month or two later, where she just started punching our egg-laying hens. As it turns out, she had been dwelling on being haunted by the dead, being attacked by the werelizard mayor, and losing family.
Another child who had similarly been haunted by the dead also threw a few tantrums, including one where the two attacked the (new) mayor together while conducting a meeting. The times they attack other citizens (or their pets?) seem to enter the Justice system (as "Disorderly conduct" cases), and some time in a deluxe dungeon seems to have mellowed them out somewhat.
One of the adults, though, has been getting worse over time. To be fair, his lover had to be put down as a werelizard, I once tried to burrow him (as the only diagnostician in the fortress) to get the hospital to work, he needs to spend time with friends but can't make any, and he doesn't feel like his life is exciting enough because he keeps ending up in prison when something attacks. His most severe sentence was for knocking down the still, and I am strongly considering exile and/or a mission to get him out of the fort, especially after he attacked the wrong person and ended up in the hospital.