Astrocytes are star like in shape, they connect neurons. They are found in the blood-brain barrier. They serve as a filter system so anything passing from the blood vessel can not move directly to the neuron with out first passing through the astrocyte to prevent mutation of the neuron. Once the neuron is mutated or destroyed it can not be restored to its normal state or replaced.
I work at a hospital. We have patients who are prolonged alcohol and drug abusers. By the time these people come to the hospital they are already in a state where you can observe some the neurological damage caused by the alcohol and or drugs. Their thought process and motor functions are impaired. I did a little research on the Alcoholism web site. Prolong use/abuse of these drugs alter or change the chemical composition of the astrocyte, and the amount of ATP. These drugs and alcohol also impact the function and composition of the neurons. This explains why people I know personally who are alcoholics don't grow intellectlly beyond certain points, they even seem to age more aggresively than other people their same age that do not consume alcohol.
