One can receive this disorder by being the rank of 40 to 44 in Halo 3.
Signs of this disorder are degraded mental capabilities, a tendency to play horrible every game, and an irresistable urge to make excuses for their many shortcomings non-stop.
This disorder can be cured (sometimes only partially) by exceeding the rank of 44 and ascending to the rank of Brigadier.
"Hmm he must suffer from Colonelism."
"Yes indeed, his skill level is 41."