What usually causes alcohol related blackouts?

Answer 1

Alcohol is a central nervous system depressant - it slows down your mental processes. Drinking a large quantity of alcohol too quickly can cause your frontal lobes (which are responsible for consciousness) to shut down, resulting in your blacking out. However, there is a lag between consumption and mental shut down, during which you physically can consume enough alcohol to also shut down your brain stem. This can result in you literally ceasing to breath due to alcohol consumption and can be fatal if not addressed rapidly. Also, you can vomit while you are blacked out and accidentally draw the vomit down your trachea, causing a very unpleasant (and dangerous) pneumonia.

In general, it is a very good idea to avoid drinking so much alcohol that blacking out would be a possibility.