Update: HBO says the show will definitely not return in its current format (multiple patients spanning multiple episodes per week). But HBO is still in negotiations to possibly bring the show back in a different format, presumably focusing on Gabriel Byrne's character, Dr. Paul Weston.
HBO has cancelled the half hour drama In Treatment after three seasons.
Not being ad supported, HBO doesn't have to bother with demo ratings for ad sales purposes, but presumably a show's viewership is somewhat correlated with its subscriber attraction/retention potential which is important and In Treatment's viewership was tiny. It's season three finale averaged just 253,000 viewers in its original airing.
To see all our ratings and news about In Treatment, click here.