My mayor suffered from the quite common "no on to blame for a recent failure"-syndrom. He went tantrum, threw a dwarf against a wall (thereby murdering him), hit a few dwarves, destroyed a piece of furniture or two and stamped on a cat tail (no kidding) plus he destroyed the chain he was first assigned to. All in all he got ~400 days of jail.
When he got chained again the unhappy thought had already disappeared and he was "quite content" so i didn't worry he would tantrum again while sitting in his engraved cell with bed, chair, table, booze and food stockpile. It all happened around early autumn.
When the dwarven caravan arrived the liaison would head to the mayor's cell and although my mayor stated he was conducting a meeting, nothing happened. Nothing unusual there, i guessed he wouldn't be able to do that anyway.
Nearly a year passed. The liaison was still there plus a human merchant prince who had arrived during the summer. Then suddenly i got a message "a diplomat has left unhappy" (or something like that). No surprise there, right? Ok, so after a few seconds i got the message again. Seemed to me the liaison finally got sick of everything and left. But that was only partially true. A quick look into the cell and... my mayor was gone. But the liaison still stood there like nothing happened plus a nearby engraver, who was just taking a drink from the booze stockpile, suddenly got struck by melancholy and went insane. wtf?
I checked on the mayor just a minute or two before he disappeared (he still had about 50 days left). What the hell happened to him?