Nobility induced psychosis and mania.
The mere act of being selected for nobility induces severe and irreperable mental harm to dwarves, causing them to tantrum because somebody has a more expensive bed than them, works in a better office, or slaved over building a family member a better coffin than thiers.
This disorder can manifest as bipolar disorder, at times with flares of mania, and others with dire, melancholic and violent tantrums.
The disorder can manifest many sympthoms, but the most common are insane demands for rediculous and or impossible items to be created, such as slade toy boats, or crystal glass beds. In addition, sufferers of this disorder often develop severe fettishistic behaviors, surrounding themselves with specific items, and even making very specific demands for specific rooms.
One noteworthy case had demanded the construction of over 78 green glass armor stands, and demanded that a brass one be installed in his mosoleum. The armorstands were forbidden from being sold, and accumulated mysteriously in his quarters.
The only known cure for this affliction is a thereputic, and prolonged immersion in a hot magma bath. Sadly, this also proves fatal to the afflicted dwarf as well. Some sufferers have even been reported self-administering this treatment option, suggesting that the afflicted are aware of their plight, and desperately seek release from the torment.
The finest dwarven psychologists from all over the multiverse are hard at work creating novel ways to apply this treatment, in the hope of creating an acceptable survival and cure rate. To date, several thousand cumulative cure attempts have been made, with very few survivors. The prospects of curing the disorder are bleak, but we still hold out hope of one day finding a cure.