Four stars (PG-13)

Never trust star ratings. The whole star rating system may seem like a dandy little time saver — very useful what with everybody’s busy now-a-go-go lifestyles — but you don’t get a sense of a film by glancing at a star rating. To get any inkling of what a movie is all about, you’ve got to do some reading.

Take, for example, The Diving Bell and the Butterfly. I’ve given the film four stars (out of a possible five). It certainly deserves them. The movie takes a book that some considered unfilmable and turns it into an unforgettable representation of a mostly interior chronicle.

The star rating, though, doesn’t tell you how harrowing the film really is. I deeply respect The Diving Bell and the Butterfly, but I spent much of the film’s 114-minute running time alternating between feeling anxious and feeling so depressed that I wanted to curl up into the fetal position and stay that way until somebody gave me a hug.

I’m not supposed to say any of that, of course. I’m supposed to simply gush about how the production is intense, imaginative and moving, but when a movie knocks you over with a roundhouse punch you’ve got to let people know.

Julian Schnabel (Basquiat, Before Night Falls) directs the adaptation of the memoir of Jean-Dominique Bauby, who suffered a stroke and awoke from a coma to discover that he was suffering from “locked-in syndrome.” Completely alert and aware, he was unable to move, to express himself. The only action he was capable of was blinking one eye.

Over time, communication is established. At first it’s “blink once for yes and twice for no,” but eventually a system is developed where the caregiver recites the alphabet, beginning with the most commonly used letters, until Bauby blinks, then begins the process again for the next letter. If that sounds excruciatingly tedious, it is. Remember, though, the film is based on the memoir Bauby wrote by blinking one letter at a time. Still, I grew anxious watching the system in use. By the umpteenth time I heard the caregiver begin to recite the alphabet anew, I wanted to head for the hills. But I didn’t, and, if you decide to see the movie, neither will you.

My impatience with the alphabet recitations paled next to the depression I felt over Bauby’s situation. For the first part of the movie, Schnabel only lets us see the world from Bauby’s point of view. There are few experiences I can imagine worse than the one the French Elle magazine editor-in-chief found himself in, and Schnabel does not allow you to distance yourself from it. Later in the film, he pulls his camera back far enough to show us Bauby’s world from the outside, but don’t expect to feel a sense of relief. The Diving Bell and the Butterfly is devastating. Expect to be shaken.

Now aren’t you glad you read the review and didn’t just glance at the stars?