The fear in major studio pictures tackling subjects such as mental illness and physical handicaps—particularly ones based on true stories—is their tendency to soften the reality and turn them into sickeningly sweet, artificially upbeat celebrations of life and rising above adversity. That is exactly what the trailers and television ads for "The Soloist" have suggested, and it didn't exactly arouse much promise for the finished product. Having now seen it, while the film does not escape every trap of the Hollywood mainstream, there are enough truthful notes of authenticity in the treatment to surpass expectations. And, if "The Soloist" is but a crisscross of elements from 1990's "Awakenings," 1996's "Shine," and 2007's "August Rush," it at least knows how to capture one's emotions without coming off as blatant manipulation.

"The Soloist" is based on the non-fiction book by Steve Lopez, a Los Angeles Times columnist who wrote about his unlikely friendship with a homeless, schizophrenic, ex-Juilliard student named Nathaniel Ayers. Director Joe Wright (2007's "Atonement") casts Robert Downey Jr. (2008's "Iron Man") as Lopez and Jamie Foxx (2007's "The Kingdom") as Ayers, and both actors have enough grit to their looks and performances to sell their roles. Granted, Downey Jr.'s rough appearance at the onset has more to do with a bicycle accident that his Steve Lopez is involved in at movie's start. With half of his face scraped up and one of his eyes bloodshot, he waltzes into his newspaper job looking not far from a bum himself. When he happens upon Nathaniel Ayers playing the violin in a nearby courtyard, and later runs into him again below an overpass, Lopez sees great potential in writing a story on this peculiar musical talent who has found himself living on the streets. The more time the two of them spend together, and the more that Lopez attempts to better his pal's situation, it becomes clear that Nathaniel is far more troubled than originally gleaned and may be beyond the point of any substantial help.

Adapted for the screen by Susannah Grant (2007's "Catch and Release"), "The Soloist" flirts along the line of cutesy melodrama without crossing the point of no return. Director Joe Wright may not always be able to resist self-indulgence—a scene in which the sounds of Nathaniel's cello-playing drifts heavenward as two pigeons soar across the city and up into the sky is a needless flowery flourish—but credit the filmmaker for tending to the story with a pace and tone that meld commerciality with an art-house mentality. The music score by Dario Marianelli (2007's "The Brave One") is blessedly understated, only used when needed and not always accompanying sequences that a more obvious film would take advantage of in order to claw at the viewer's heartstrings. By allowing the characters and the world they are in to play out and breathe, both become more real and intimate. This is certainly evident in the interludes set at LAMP Community, a Skid Row-based ministry service housing the homeless and disabled that Lopez visits in an attempt to aid Nathaniel. Through on-location shooting and the casting of actual residents of LAMP, these dynamic scenes are transformed with a documentary-like immediacy and all-important credibility. Meanwhile, the ending montage wherein the characters dance together among the patients and residents of LAMP takes things too far and is one of the few instances where the film overtly stumbles into treacly territory.

If Nathaniel's love for classical musical goes unexplained—it is just as well, since all of our own respective loves are not so easily summarized—director Wright almost achieves a wordless answer in a minute-plus set-piece where Nathaniel closes his eyes and listens to Beethoven as a fantasia of colors overtake the darkened screen. It is a bold cinematic choice, and one that pays off. Undoubtedly a difficult role to tackle, Jamie Foxx gives a surprisingly controlled, multifaceted performance as Nathaniel Ayers. Foxx does not turn Nathaniel into a lovable quirk, but into an aging, kindly man whose pure talent has been tarnished by a disease he has been too sick to recognize that he has. As with his ailments, Nathaniel can be stubborn, unpredictable, infuriating and frustrating, and Foxx captures all of these things without losing sight of the character's humanism.

As Steve Lopez, Robert Downey Jr. is effortless in his turn as someone a bit less aggressive than the actor's usual roles. Likely as a result of being based on his own book, Lopez is written to be a virtual saint—a do-gooder who connects to Nathaniel and platonically falls in love with him—and while this could be seen as a flaw, Downey Jr. makes it wholly believable and even touching. In memorable supporting roles, Catherine Keener (2008's "Synecdoche, New York") brings vibrancy and dimension to Lopez's ex-wife and co-worker Mary Weston, and Lisa Gay Hamilton (2008's "Deception") is a stirring, unforced dramatic presence as Nathaniel's estranged sister Jennifer.

"The Soloist" does not arrive at any easy answers in the end, but does find a positive, bittersweet note to conclude things on (the trite aforementioned dancing epilogue not included). The film—a paean to mental impairment, Bach and Beethoven, and, like the recent "State of Play," a shrinking 21st-century society of print publications—goes down with ease, more involving to watch unfold than anticipated. This is a particular achievement considering how bland the general plot is and how quickly it could have fallen into mawkishness. "The Soloist" takes its share of wrong turns—the anti-medication stance held by some of the characters and, apparently, the makers, feels narrow-minded and careless—but Robert Downey Jr. and Jamie Foxx make a terrific onscreen pair. The friendship between Lopez and Ayers, more than even the music, is where its soul lies.