Well you at least sound like you're lucid and sane. It also sounds that what you're experiencing is all related. So if you have had multiple head injuries in the past it is possible that whats going on is because of them. I wouldn't say the weed re-wired you're brain. Marijuana is a drug that simply inhibits the neurons from firing properly. For example brain cell A encounters THC and it stops sending signals to brain cell B and instead sends them to brain cell C, D, E and F. This is what causes the "high" sensation. But the weed doesn't do anything that has a permanent affect, physiologically speaking. If on the other hand you are prone to mental illness the weed can induce episodes. Schizophrenics can have episodes if they smoke weed. Taking certain medications can also cause a reaction to the weed. No if your brain got re-wired it was the speed, x and mushrooms, and what ever other hard drugs you might have taken, that did it.
Maybe what you should try to do is talk to your voice. Try to understand it and perhaps figure out any sort of motivations. If this voice is hostile you must assert your dominance and never ever do what it asks. Giving into any demands it may make would only drive it into a full blown mental illness (Think of the Son of Sam). Really though I still think you should see a doctor to get your head scanned to avoid any further permanent damage.
--------------------
|