extending REM duration?

[mongreloctopus]

Anyone know of or read anything about extending the duration of REM stage? There must be some external way to influence the sleep cycle.

[Darkhack]

I know (from my psych class last semester) that children are in REM sleep longer and that drugs/alcohol reduce the amount of time spent in REM. I also know that if you are awake for very long periods of time that you go into REM sleep faster and spend more time in it. Other than that, I don't know a whole lot about the time spent in REM. Thought I would mention this though.