Other people’s hallucinations, like other people’s dreams, don’t make the most interesting party conversation. But any artist worth his salt flirts with the far side of sanity once in a while, and accounts of madness often wind up on stage. When it works, audience members let their own boundaries slip – those who saw the original production of Peter Brooks’s “Marat/Sade” still talk about the sensation of losing control. Too often, though, depictions of mental illness purple into cliche, embarrassingly self-indulgent performance, and the too-predictable abuse of lipstick.

The revival of actor-director Dario D’Ambrosi’s “Nemico Mio” (redubbed “Dreaming the Sea”) now at La MaMa, waffles between the two extremes. An appealingly odd situation (two mental patients seem to sun themselves on the beach while rehearsing the very situation that got one of them committed) benefits from Mr. D’Ambrosi’s first-hand research in an Italian asylum. So powerfully did those three months affect him that Mr. D’Ambrosi, has made a career out of playing crazy: He even named his theater company Teatro Patologico. For 25 years, the bruiser size clown has toured his work to La MaMa, always nudging audiences closer to the nightmarish edge of the truly mad. But even after decades of experience with insanity, a master of the irrational can tire, and this most recent production certainly has bags under its eyes.

On a stage gently sprinkled with sand and surrounded by childish finger-paintings of the sea, an orange safety raft lies in a heap. While sighing winds and whale-song drift about, a man (Mr. D’Ambrosi), dressed in pajamas with a paper bag on his head, shleps in buckets of sand to this rather makeshift “beach.” Surrounding it are lines of barbed wire, beyond which lies … more sand. Our figure with his bucket brings in a scrawled sign reading “Ciao” and tosses it over the fence into no-man’s land. Nobody replies.

A madman counting grains of sand and a safety raft with a puncture – it’s a delicious pile of allegorical possibility. Unfortunately, Mr. D’Ambrosi knows it. When the timid Tommaso (Lorenzo Alessandri), hiding inside the raft, emerges as a mute with a submissive streak, Mr. D’Ambrosi loses no time in calling him the president. When Mr. D’Ambrosi himself, after doffing his paper bag hat, decides he may kill Tommaso “rather than tell the truth,” again, he brings up politicians. Government today, it’s insane! Get it?

The two men dwell almost entirely in fantasy, using each other as props when necessary. Unfolding a pull-out spread from a nudie magazine, they take turns lying down and impersonating the centerfold. When one of them remembers a wife, now dead, the other sportingly puts on a bit of makeup so they can slow dance. Fascination with their own bodily functions takes up the rest of their time. In one sequence, both adorable and disgusting, Tommaso preens over his product for the day: an extremely large pile of excrement. Even Mr. D’Ambrosi gets excited at its dimensions – he splashes around in it like a tot in a wading pool.

Screeching announcements from a speaker remind the poor “vacationers” that these are asylum grounds. Soon, the two sunbathers will have to report back to their cells. This comes as no surprise, but certainly is welcome. The extreme tics and uncomfortably jerky pacing have long since turned into a discombobulated string of “nuttiness,” and the initial allure of the beach-prison has become stultifying.

When Ellen Stewart first asked Mr. D’Ambrosi to La MaMa, he performed solely in Italian. Now, he does his work in a strange mix of languages. Rattling along in Italian, he will suddenly interrupt himself with an English translation. Snapping us in and out of understanding, Mr. D’Ambrosi actually torpedoes his chances at creating a trance-like atmosphere. It’s the familiar numbness of hearing about another person’s dream. The harder the actors work to convince us, the more their capers seem impenetrably self-indulgent.