Many people experience "sensory overstimulation," where they feel like you are bombarded by sensory input, such as sights and sounds. This can be more common in disorders such as ADHD, Aspergers, and autism.
A woman who experienced this sensory overstimulation found that it subsided about 20 minutes after taking a potassium supplement. A neurologist found that her symptoms were the same as in "hypokalemic periodic paralysis," where ion channels in the muscles become overactive when potassium levels are low. The woman found that eating a high-carb diet and eating salty foods triggered her sensory overstimulation, just like in hypokalemic periodic paralysis.
The family studied also seemed to not react to lidocaine. The son had a lidocaine shot and it didn't even seem to work. There appears to be a connection between the way that lidocaine is processed and the other difficulties the mother was describing.
While the association between potassium, ADHD, sensory overstimulation, and resistance to lidocaine is not clear yet, it does open some interesting avenues for further research.
I wonder if the resistance applies to all "-caine" drugs, like novocaine? When I have my teeth drilled, I have to get the maximum dosage of novocaine, and then it wears off in about an hour. That might explain it. Time for me to go pop some potassium tablets!