1
general::
1. Surprise, shock, or amaze one, as in This jazz group blows my mind, or Joe served a jail sentence? That blows my mind. This term is used rather loosely, as seen in the examples; the first signifies amazement and pleasure, the second shock and dismay. [Slang; 1960s] 2. Alter one's perceptions, especially through drug use, as in Taking LSD really blows one's mind. [Slang; 1960s] 3. Make insane, drive crazy, as in Was it his wife's death that blew his mind? or Losing her savings blew her mind. [1960s]
American Heritage Idioms