IT DOES NOT PUT HOLES IN YOUR BRAIN. Thats a misconception of the pictures shown to people of decreased brain activity.
however i would never advocate this drug as i am a former abuser. drugs affect everyone differently and honestly the only source of long term effects i believe are the ones ive suffered (since the studies of the drugs are done on animals which are difficult to transfer over to humans, or the studies are done on people after the abuse, not before so its hard to know what differences its caused in a persons life since there is no substantial proof of how the person lived before hand).
anyway, so i abused for two years. i became a heavy user after one year, taking up to ten pills at a time, and i mean all at once.
the long term effects i suffered from were: insomnia (diagnosed by my psychiatrist). i was 25 pound under weight when i decided to stop. heavy mood swings which lasted about a year. depression (suicidal thoughts), which lasted roughly two years. i felt slow and found it hard to concentrate on anything or to learn new things. i developed compulsive behaviors like spending large amounts of money on clothes, gambling, my car..etc. heavy decrease in sexual appetite. the hardest part is getting over the urge to do it, that took about two years before i could say no with strength though there are nights where ill randomly crave it. the cravings continue to decrease as time goes on but its the hardest thing the deal with out of all the long term side effects.
not everyone becomes an addict, and if you did it just once youd probably be fine, however, ive never met anyone whose done it just once. and to answer your question about brain damage…there aren’t any reliable sources that say it does.