Compelling, interesting for 90%--but not enjoyable for 10%

Rating: 8/10 (29 December 2010)

A young ballerina ("Nina"/Natalie Portman) is held in an imprisoning relationship with her single mother (Barbara Hershey) who, herself, had been an aspiring ballerina until....
It's never explicitly stated but it's easily inferred that the mother's career ended when she became pregnant with Nina after an affair with her ballet master and that she's trying to fulfill her own thwarted ambitions through guiding Nina.
What we see in Nina is a young woman with a reliance on her mother more typical of a 9-11 year old girl (and with a similar stunted personal maturity), trying to fulfill mother's desire to be the perfect ballerina her mother wished to be and avoid any romantic relationships (which could interfere with reaching that goal as it had for her mother).
Nina suddenly has a chance to dance the role of the Swan Queen (the white swan) in "Swan Lake" but must also dance (as standard for this ballet) her nemesis' role, a look-alike black swan. As the virtuous White Swan, Nina's perfect but her ballet master (who aims to have sex with Nina) keeps badgering her to be sexier, more seducing as the non-virtuous Black Swan. This, of course, clashes with Nina's mother's upbringing of Nina.
This clash provokes a developing psychotic reaction which Nina does not recognize--and, for awhile, neither do we, the film's viewers: we react to some scenes as actual experiences of Nina only to find out later that those episodes were the stuff of Nina's psychosis. And we leave the theater very unsure of how much of what we saw of Nina's experiences were real or her hallucinations. I'm sure our fascination with this uncertainty and trying to unravel the tangle of reality from insanity contributes much to what drives many viewers to be fascinated with this movie. (E.g., look at the questions and debates on IMDb's Message Board for this film.)
IMO, the pathological relation between Nina and her mother that sets up what follows was exceptionally well done by Portman and Hershey. There's enough similarity in their facial features that we easily see them as mother and adult child. All the other cast members ("Lily"/Mila Kunis as a real world seductive Black Swan and rival; Vincent Cassel as the preying ballet master) seemed perfectly chosen and gave excellent performances. My movie companion (who took ballet for years) said the scenes of ballet practices were authentic.
IMO some of those therapists experienced in treating personality & psychotic disorders (especially including the various schizophrenias) may be among those having quibbles with "Black Swan." E.g., the clash between Nina's internalized aims of her mother vs. those of her ballet master would certainly provoke a massive conflict within Nina. But a depressive reaction would be far more likely and, if a psychotic reaction did occur, there'd surely be noticeable disorganization between her episodes of hallucinations (i.e., she'd not be able to function or dance normally between those psychotic episodes).
But captivating narratives have never had to strictly follow reality to make them enjoyable--e.g., "Alice in Wonderland," "Kiki's Delivery Service," "Star Wars," "Harry Potter," the "Twilight" vampire series, and hundreds of others. "Black Swan" is an entertaining, psycho-fictional, horror movie--it's NOT a realistic case study or documentary.
I think IMDb's current rating of 8.7 of 10 stars and Ebert's rating of 3.5 of 4 stars are both representative of how most of the general public will react to this film.
I think a 4 or 5 of 10 (or even less) could be more typical by some of my shrink brethren with much mental health experience dealing with psychoses as well as from those offended by the lesbian sexual content or the gore.