Sadness alert: Showtime's strongest comedy series, "United States of Tara," will take a significantly dark turn in the second half of this season. Thankfully, its quirky brand of humor remains intact, making the series as compellingly schizophrenic as its lead character is.

Sadness alert: Showtime's strongest comedy series, "United States of Tara," will take a significantly dark turn in the second half of this season. Thankfully, its quirky brand of humor remains intact, making the series as compellingly schizophrenic as its lead character is.

It's an interesting combination of emotions that could polarize fans. Some may feel it's some of the series' finest, while others will be turned off by the deviation. Having seen the entire season, I'm a proponent of this shift.

The show has always kept a good balance between the inherent drama associated with Tara's (Toni Collette in I-want-my-Emmy-back mode) dissociative identity disorder and wonderful moments of levity.

And Season 3 has presented many of those moments: Neil (Patton Oswalt) giving his daughter the middle name "Wheels" - quotation marks and all - because he wants her to be fast, Max's (John Corbett) incorrect OrgaLawn uniform that says his name is "Greg Maxson," Marshall's (Keir Gilchrist) self-deprecating quips and Kate's (Brie Larson) teddy-bear dress.

Even Tara, her alter egos and psychologist Dr. Hatteras (Eddie Izzard) contribute some humor, but it all - except Kate's fabulous fashion sense - emanates from a family being torn apart by a mother's psychosis.

So the emergence of a new alter ego - who says the cryptic line, "You will not win," in the most recent episode - marks a sinister, and occasionally downright horrific, twist on the season.

As Tara and Hatteras work to expel her alters, even though Hatteras doesn't believe in D.I.D., things become very messy for the two of them.

Hattaras' no-nonsense approach means Tara and her family must fully recognize that she is crazy, and when the good doctor tells Max she may never get better, he's clearly crushed. He'd always known it was a possibility; it just never seemed as destructive as it does here.

Tara's downward spiral creates excellent material for Collette, Izzard and Corbett, but it's very uncharacteristic of a "comedy" - so much so that it takes those excellent bits of humor to remind me that's what "United States of Tara" really is.