Ed Harris and the cast of Good for Otto by the New Group. (Photo by Monique Carboni)

Probably the most generous way to think of David Rabe’s Good for Otto is as a heartfelt tribute to the world of public mental health. Those who provide treatment — Dr. Michaels (Ed Harris) and Evangeline (Amy Madigan) — and those who seek it are given equal time and compassion by the admiring playwright, and each camp emerges as heroic. (Unsurprisingly, it’s the insurance industry that comes off negatively.) In several touching vignettes, we get a visceral sense of the pain, frustration, and, yes, the victories that keep it going. There is, indeed, some light at the end of the tunnel.

Whether all this makes for a workable play is another story. Vignettes are one thing, but cohesiveness is another. As seen in a New Group production at the Signature Center, directed by Scott Elliott with a fluidity and visual panache that sometimes undermines the script, Otto emerges as rambling and episodic, feeling both unfinished and overlong at three hours. Well, they don’t call psychotherapy “the talking cure” for nothing.

Otto’s best moments come early — in particular, a three-way conversation about suicide that goes far beyond the usual bromides. In a scene that includes Dr. Michaels; Jane, the grieving mother; and Jimmy, the man who killed himself (he’s a kind of commentator, strumming his guitar as he talks), the very impossibility of explaining how a normal day can suddenly turn devastating feels like a gut punch. (All three actors — Harris, Kate Buddeke, and Michael Rabe — are superb.)

But as more patients come and go, the focus gets lost amid too many storylines. Some are effective (F. Murray Abraham in a fine turn as a senior coping with diminishing memory and vitality), while others feel shticky (Mark Linn-Baker as a man who can relate more easily to his hamster — the titular Otto — than to other human beings). A significant plot thread involves Frannie, an increasingly agitated and violent little girl, who will likely become a casualty of the health care system. Rileigh McDonald, an astonishing young actress, brings the character vividly to life, but we’ve seen similar stories before.

Act II introduces us to Alex (Maulik Pancholy), who is panicked primarily about his sexual orientation. Pancholy is immensely likeable, but his performance veers awkwardly between energetic comedic charm and seriousness. It’s also problematic and outdated  to find gay identity thrown into a mix of desperate people coping with psychiatric disorders.

Oh, and periodically throughout Otto, there are singalongs. (No, I can’t explain them.)

It’s all too much — though if Rabe intends for us to empathize with the fearsome sense of overload caregivers experience, he succeeds many times over. Add to this Elliott’s busy direction, which puts several of audience members seated among the actors (the latter mostly remain onstage even when they’re not featured). The general effect suggests a town meeting, which doesn’t work on several levels. As a metaphor — we can’t distinguish the patients and doctors from everybody else — it’s too obvious. More damagingly, it robs the therapy sessions of a fundamental sense of privacy. As anyone who has undergone analysis knows — and as the TV show In Treatment (which Good for Otto sometimes recalls) dramatized so effectively — psychotherapy is perhaps the most intimate act one can undergo, more so even than sex. To set it amid a group of onlookers is to coarsen and dilute it.

Good for Otto is David Rabe’s first new play in New York since 2012. The stellar cast assembled here is a testament to his reputation as one of America’s major writers. And indeed, much of Otto shows that Rabe’s extraordinary facility for language and theatrical orchestration remains vital. But though his heart is in the right place, Otto is both not enough and way, way too much.

Good for Otto by the New Group plays at Signature Center in New York through April 8. For more information, visit the website.