No pun intended. There’s also some good background on his chemical dependency:
Paul Filho on rehab, Sonnen rematch - Watch more free videos
(Thanks to MMAmania.com reader “Roy” for the assist.)

He did. He didn’t. He did.
WEC Middleweight Champion Paulo Filho has indeed officially opted to postpone his 185-pound title fight against Chael Sonnen scheduled for March 26 because of a substance abuse problem, according to WEC.tv.
No date for the rematch was disclosed nor was the “substance” identified.
Here’s a snip from his manager, Ed Soares:
“This is […]

Despite numerous reports that he was postponing his rematch with Chael Sonnen (19-9-1) on March 26, WEC Middleweight Champion Paulo Filho (14-0) will indeed headline the upcoming WEC event as scheduled.
In addition, the WEC announced the entire March fight card this week.
Filho’s participation in the March event was confirmed by his manager, […]

The rematch between undefeated WEC middleweight kingpin Paulo Filho and Chael Sonnen has been postponed to June 1 in Sacramento, Calif., according to the Brazilian MMA Web site Tatame.com.
However, the reason for the postponement is a bit puzzling. The movement of the rematch was apparently requested by Filho. Though no official reason has been cited, […]

Whether it’s a show of sportsmanship or a chance to redeem his past performance, WEC Middleweight Champion, Paulo Filho, has reportedly accepted a rematch against Chael Sonnen for the 185-pound title in March, according to Tatame.com.
The showdown could also possibly mark the last fight for the Brazilian at middleweight.
Here’s the snip:
“WEC Champion at 84kg category, […]