Caden Cotard (Philip Seymour Hoffman, right) is a middle-aged theatre director whose marriage to artist Adele (Catherine Keener) is falling apart in Charlie Kaufman's Synecdoche, New York. (Equinoxe Films)

There is a reservoir of sadness buried inside Charlie Kaufman, the wildly inventive screenwriter behind Being John Malkovich, Adaptation and Eternal Sunshine of the Spotless Mind. In Synecdoche, New York, his directorial debut, that sadness finally seeps out and threatens to swamp us.

The movie is a riff on time and mortality featuring one of those great, absurd Kaufman conceits — in this case, a gigantic, ongoing theatre piece that strives to mirror real life. Only this time, the absurdity is dampened by an overwhelming sense of quiet despair. Kaufman begins by poking fun at the autumnal and melancholy, only to end up making a picture that is autumnal and melancholy, to the point where it smothers the comedy.

It’s disappointing, because the first half of the film is one of the best things he has ever done. Adopting a grimly humorous tone, Kaufman introduces us to Caden Cotard (Philip Seymour Hoffman), a middle-aged theatre director with a stalled career and a body that’s beginning to fall apart. The pupils of his eyes aren’t dilating properly, pustules are popping up on his skin and his urine is the colour of rust. His marriage isn’t in any better shape. His artist wife, Adele (Catherine Keener), barely notices her deteriorating hubby — she’s too busy tending their demanding four-year-old daughter (the delightfully natural Sadie Goldstein) and preparing for an upcoming exhibition in Berlin.

The family lives in a ramshackle old house in Schenectady, N.Y., where Adele paints delicate miniature portraits in her basement studio while Caden directs plays for the local theatre. Kaufman rubs our noses in the grungy details of their poor-artist existence — the grimy walls, the malfunctioning plumbing — as well as Caden’s mounting list of bizarre ailments. There’s enough physical decay here to fill a late-period Philip Roth novel. And like a Roth novel, it’s morbidly funny.

As it turns out, the marriage crumbles well before Caden does. Adele takes off to her Berlin show with their daughter, becomes an art-world star and doesn’t come back. Caden is left devastated. In consolation, the gods — in the guise of the MacArthur Foundation — shower him with one of their $500,000 “genius grants.” Perhaps in reaction to Adele’s micro-sized art, Caden decides to use the money to stage a massive theatre project based on his own life.

Taking over a vast, abandoned warehouse in Manhattan, Caden has life-size sets built to duplicate his Schenectady surroundings and auditions a huge cast. They begin rehearsing scenes from Caden’s day-to-day existence — including scenes of him directing the scenes. Actors play Caden and the people in his life, such as Hazel (Samantha Morton), the box-office attendant who carries a torch for him, and Claire (Michelle Williams), his actress lover — who is also acting in the project. (Got that?) When the actor playing Caden (Tom Noonan) falls for Hazel and the real Caden falls for the actress playing Hazel (Emily Watson), that becomes part of the work, too. As the sets grow more and more elaborate, it grows difficult to tell the real and false worlds apart.

Caden (Philip Seymour Hoffman) spends decades rehearsing his mammoth play, with the help of his faithful assistant, Hazel (Samantha Morton). (Equinoxe Films)

Caden’s play, a grand theatrical folly that remains in perpetual rehearsal for decades, may be Kaufman’s send-up of the kind of mammoth projects staged by avant-garde directors like Robert Wilson and Robert Lepage. Caden’s desire to turn his every waking moment into art is a satire of the solipsistic artist, taken to the extreme. Yet the comedy is undercut by an elegiac tone that kicks in midway and never lets up. Even the many touches of surreal whimsy — Hazel lives in a house that’s slowly burning down; Caden continually sees himself embedded in television commercials — fail to lift the pall. The hero’s unending melancholia hijacks the movie.

Caden is another of Kaufman’s sad-sack artist-heroes, like John Cusack’s unappreciated puppeteer in Malkovich and Nicolas Cage’s blocked screenwriter (name: Charlie Kaufman) in Adaptation. Caden is the kind of pathetic lump that the likable Hoffman plays with ease. If anything, it’s a role he’s played once too often. You wish Caden at least had some of the asperity of his drama professor in The Savages. Instead, he comes dangerously close to the maudlin self-pity of the gas huffer in one of Hoffman’s worst films, Love Liza.

Kaufman surrounds him with a dream cast: Keener, Williams and Watson, as well as Jennifer Jason Leigh, as a pretentious, predatory lesbian, and the superb Dianne Wiest, as an older actress with the cool composure of Dame Judi Dench. Morton is especially good as lovelorn Hazel. Buxom, playful and gently seductive, she has the vivacity that you hope will lift Caden out of his mortality-obsessed funk.

It’s a misplaced hope — Kaufman’s outlook here is bleak. We might have guessed what he was up to early on, when Hazel mentions she’s reading The Trial. Caden’s play — and the film — wind up being like the plot of a Kafka novel: a convoluted exercise in futility. And Caden turns out to be a variant on Kafka’s Hunger Artist — an artist devoured by his own art. That might explain the film’s punning title. A synecdoche is a figure of speech in which a part represents a whole, or vice versa. For Caden, the part that represents his life — his play — ends up being the whole of his life.

This film was originally going to be helmed by Spike Jonze, who directed Malkovich and Adaptation. If he or someone other than Kaufman were directing, they might have emphasized the irony in his script and let us laugh more at its determinedly dour outlook. Then again, maybe Kaufman had to direct this film himself; for all its flaws, it’s still his most complex and mature work to date. Synecdoche, New York leaves you depressed, but also convinced that he’s one of the most original minds working in movies today.

Synecdoche, New York opens in Toronto on Nov. 7; in Calgary, Montreal, Vancouver and Victoria on Nov. 14; and in Ottawa and Winnipeg on Nov. 21.

Martin Morrow writes about the arts for CBCNews.ca.