Status: Open.

Endorphins are the brain's natural pain killers: its answer to the short, sharp shocks that life can throw into your path.

It has long been known that endorphins can be stimulated by other means too: physical exertion, music, prayer. And they are known to be addictive, in the sense that prolonged exposure can lead to desensitisation: you need more to get high.

The 'dazers' mentioned in passing in 'Earth' have gone one step further in discovering how to continually stimulate endorphin production.

Michael Crichton's novel 'The Terminal Man' also dealt with this issue.

Reality

Leaving aside genuine meditators, there is, as far as I know, no indication that anyone is able to induce this state at will. However, it is possible that some may be doing it unconsciously doing it.

Brin's attention has recently shifted to those who use indignation to get their fix. The thinking being that the fix enforces the indignation, which in turn discourages any rational assessment of the source of the indignation. When this behaviour becomes apparent in areas that involve a high level of social responsibility (eg the political and legislative processes), then it becomes a liability that affects everyone. Think abortion! Think gay marriage! Think (ironically) the 'war on drugs'!

(Brin is seeking evidence to support this theory: see the open letter [2])

On the flip side, biofeedback techniques such as this can be beneficial. Researchers at Stanford University have recently had some success in using computer games to suppress depressive tendencies in teenagers known to have risk factors [3]

References

1. http://www.spectrum.ieee.org/mar06/3044
2. An Open Letter to Researchers of Addiction, Brain Chemistry and Social Psychology from David Brin
3. Brain-training games stop depression before it starts , New Scientist, Nov 1, 2011