Perhaps another example is Keith Richards, who says heroin helped him and he doesn't regret it (and then, do we measure the positive impact such music has on other people?). Although dipping into artists for drug use is perhaps too easy of examples.
Goering was forcibly institutionalized for six months due to his morphine addiction. During his institutionalization he was strait-jacketed due to his violent behavior to the staff. He was already a leader of the NASDP that this time, having been injured during the Beer Hall Putsch.
He gained an enormous amount of weight and his behavior was viewed as increasingly bizarre and erratic over the course of his 'career'. He didn't quit until be was forced after his arrest and imprisonment at Nuremberg, where I believe he quickly lost 80-100 pounds.
It is really unclear how either of these individuals represent an example of the positive power of opiates. At best they seem to have managed to hang on despite their addition to opiates.
No comment on Keith Richards :)
While not as physically safe as LSD, opiates have essentially no serious long-term health effects other than constipation. The major downside is the highly visible acute respiratory depression after overdose.
Edit: Speed is used by tons of people, and Paul Erdos said it gave him inspiration (though methamphetamine might have more downsides than other amphetamines, similar to how barbiturates are rather outclassed by benzodiazepines - but that's hardly reason to outlaw it). Many artists have used cocaine to their benefit. I'm all for psychedelics, but don't pretend that other medicines don't have plenty of value.