This is a great piece by Russell Brand, explaining the inexplicable, drug and alcohol addiction. It's particularly helpful in understanding the Philip Seymour Hoffman story, even though it was written almost a year ago. There's something about addiciton that people who have never come across it don't understand (and by the way, who are these people?). How could someone who has it all throw it away? Is there a profound unhappiness within that person? Not necessarily. They may be perfectly happy. They may have everything going for them. But they just can't stop.
It sounds implausible, but I've seen it.