From my own experience I know that when I adapt articles on Wikipedia to a more neutral or evidence based point of view on a topic as e.g. electroconvulsive therapy it is reversed to the original text in a matter of days to weeks.
To my opinion you must view the information on Wikipedia as opinion based information and not necessarily as evidence based.
In a recent debate on blogs between David Rothman and ScienceRoll this subject gets thorough attention. I agree with the latest statement of David Rothman: Having lots of references does NOT equal accuracy, credibility or authority.
One should be aware that due to fact that Wikipedia is written collaboratively by volunteers from all around the world not so objective subjects might volunteer as well.
Even Dutch Royalty rewrite the article about them on wikipedia