Top graphologist Frits Cohen said that the handwriting painted a picture of a "logical, but obsessive man with an inferiority complex".
At the same time, he added, it showed a man with intense passion and desires which he kept "bottled inside".
Studying a letter written by Hamilton to Michael Forsyth, the Secretary of State for Scotland, last month, Mr Cohen said the handwriting revealed that the writer clung to the past "but was determined and deliberate in his actions".
"He was a volcano. This man had bottled up tensions and did not know how to deal with them. His outburst comes because he could not cope with these tensions."
The analyst added that the letter showed that Hamilton could not cope with daily life. "His writing sticks closely to the line and to the left hand margin, which shows that he clings to the past.
"His alternation in slant to the left and right show the need for contact with people but also distance."
Mr Cohen said that the writing revealed that he had an inferiority complex and was narrow-minded, "but underneath it all he was a warm, full-blooded man who was probably sexually frustrated".Reuse content