It's an expensive way of turning yourself into a gobshite for a couple of hours.
The hangover, comprising of a spell of depression, sometimes doesn't arrive for a couple of days, but can sometimes last for a couple of days.
Washing it up just makes the whole package more intense.
Sustain the input and all sorts weird stuff can happen, mood swings, lengthy spells of depression, 'colds' that last forever and misfiring neurons - One of my mates freaked out badly in a cab once, convinced there was mouse running loose in his trousers. More commonly it feels like insects crawling all over (or under!) the skin.
Never really understood the appeal, but some people really like it and Ruge is one of those by the looks of it.
On the positive side, a couple of my mates came back from the edge after having kids - It's a real reason for knocking it all on the head.