Ps. In later stages one will find the autism like symptoms like withdrawal,need to create ORDER in a chaothic world, extremely closed type of person, fear of being attacked from behind, delusion everyone is an enemy etc.
I actually see this a lot in the mental hospital where I work sometimes.
And again these symptoms can have many causes, so we should not jump to conclusions.
There are definitely some neurological consequences to high mercury exposure. The term "mad hatter" actually comes from the use of mercury to treat the felt bowler (hats) popular in the old days. But again the symptoms you are mentioning from the late stage of mercury poisoning can occur from an imbalance of the neurotransmitters, which can have various causes itself from glandular damage to drug use.