It's time for tormented French writer-director Catherine Breillat to spring for a therapist and stop inflicting her rape fantasies and sexual self-esteem issues on the movie-going public.

Two years ago she directed "Romance," a pretentious art-porn flick about the debasing downward spiral of a woman so neglected by her boyfriend that she tries to distance intercourse from emotion in a vulgar string of carnal liaisons. Conceptually fascinating, the film was effectively pointless because the main character has no journey -- she's just as screwed up at the end of the picture as she was at the beginning.

In her new film "Fat Girl (Á ma soeur!)," Breillat applies the same raw, dark, psychosexual themes to adolescent yearnings, exploring the psyches and bodies of two teenage sisters -- one gorgeous and sensual, the other overweight and introverted.

At first the film delves into the love-hate dynamic between the two siblings. Flirtatiously experimental but emotionally immature Elena (Roxane Mesquida) is 15 years old and thrives on the attention she receives from older boys and men. On summer vacation with her family, she hooks up with a law school student (Libero De Reinzo) who pressures her to sleep with him.

Lonely and depressed 12-year-old Anais (Anais Reboux) often tags along with her shallow, heartless sister, who would clearly rather be rid of her. Elena goes out of her way to make Anais feel unwanted and uncomfortable -- to the extent that when her college lover sneaks into their shared bedroom, Elena gives into his coercion and loses her virginity as Anais lies awake in the adjacent bed, quietly crying.

This unblinking, lengthy and deliberately disquieting scene of persuasion and penetration is typical of Breillat who, to my knowledge, has never written about anything but disturbingly dysfunctional sex in her 30-year career as an author and filmmaker.

Also par for the course is the way she builds an engrossingly melancholy, manipulative, emotionally complex relationship of jealousy and ridicule between the sisters that seems to be the centerpiece of "Fat Girl" -- then wantonly abandons it for a graphic, violent, prurient and utterly arbitrary twist that illustrates nothing and resolves even less. It's as if Breillat can't cope with the intensity of her own creation and bails out in the most deliberately unpleasant way she can imagine.

Freud would have a field day with this nut, whose films seem flawed on an even more fundamental level when you consider that while Reboux and Mesquida give startlingly frank performances, the supporting players are never more than one-dimensional caricatures.

If the director had the diligence to see her story arc through to anything remotely resembling a relevant conclusion -- good or bad -- "Fat Girl" might have been a powerful, blunt contemplation of how sexual patterns can become engrained in women at a young age.

But as is, the film is memorable mostly for its shock value of seeing on-screen erections and underage actresses naked.