I asked a question earlier about cocaine healing the brain( which it doesn't i know) but what would a brain need healing from?

Cocaine : If you are using cocaine, your brain will be depleted from dopamine, and other neurotransmitters like serotonin, adrenaline and noradrenaline. The continuous use of Cocaine will leave you with a deficiency with would require healing by replenishing your neurotransmitters to a baseline level, and reducing the artificial stimulation provoked by Cocaine preventing further damage.

Lots of things: Physical or emotional trauma, drug and or alcohol abuse, infections, stroke, dementia, parkinson's disease, tumors and cancer are just a few. A neurologist will give you a much bigger list.