Based on the 2019 nonfiction podcast of the same name, “The Shrink Next Door” on Apple TV+ is the true story of a schlubby millionaire CEO of a fabric company in New York who falls under the Svengali-like spell of his psychiatrist, who eventually horns in on his money as well as his summer retreat in the Hamptons.

That’s how journalist and podcast host Joe Nocera became familiar with the pair — Dr. Isaac “Ike” Herschkopf (played here by Paul Rudd) was literally the shrink living next door to Nocera, swanning around the Hamptons abode as if it were his own. In fact, it belonged to his longtime patient, Marty Markowitz (Will Ferrell), who had inexplicably moved into the guesthouse.

This toxic dynamic began in the early ‘80s and continued unabated for three decades until Markowitz belatedly wised up, cut ties and filed a formal complaint. Nocero reported this past spring that Herschkopf was finally ordered to surrender his license to practice in New York for “violating professional standards in dealings with several patients.”

As adapted here, Nocera doesn’t exist; there’s no third party attempting to unravel this messy story, and while I’m OK with that choice, it means the title itself makes little sense except as IP podcast listeners will recognize. But that’s not the only creative decision that doesn’t fully work. A portrait of exploiter and exploitee — from writer Georgia Pritchett and comedy directors Michael Showalter and Jesse Peretz — “The Shrink Next Door” is tonally confused and often misjudged, putting Rudd and Ferrell in an untenable position where they are tasked with being simultaneously earnest while also winking at the audience, which has a way of putting their performances in air quotes. Actually, everything here feels set off by air quotes, including much of the ‘80s costuming and hair.

How much fun is it to watch a scam artist manipulate someone who is incapable of advocating for himself? “The Shrink Next Door” hopes your response will be “a lot of fun because it stars Rudd and Ferrell,” but there’s the issue of just how disturbing the story actually is. There’s a way to thread this needle, I think, with well-known comic actors taking on more dramatically probing roles without losing their sense of the comedic and absurd. Watching the show, my thoughts went to Melissa McCarthy in “Can You Ever Forgive Me?” from 2018, which is another true story of desperation and scam artistry. “The whole movie’s terrific,” my colleague Michael Phillips wrote at the time, “a little funny, a little sad, a sharp evocation of early 1990s literary Manhattan as seen from both sides of the window pane. Looking out. And looking in.”

By contrast, “The Shrink Next” door never finds that right mix. Perhaps because it doesn’t seem especially curious about the interiority of its characters — what are Marty’s longings, ultimately? — so much as it's focused on portraying the strange and wildly inappropriate connection that grew between these two men, fueled by Ike’s hubris and Marty’s vulnerability.

Like many abusers, Ike is expert at isolating Marty from the people who care about him most, including Marty’s no-nonsense sister, Phyllis (a terrific Kathryn Hahn, who is especially strong when the siblings reconnect 30 years later). Casey Wilson is also quite good as Ike’s sweet but increasingly bitter and disillusioned wife.

But this is primarily the Rudd-and-Ferrell show, and they find all kinds of interesting notes to play as a couple of Jewish guys from New York who “get” each other in certain superficial but culturally specific ways, which might explain some of Marty’s willing dependence on someone who was clearly taking advantage of him. Ike is just perceptive enough of a therapist — says just enough insightful things, with just enough emphasis — to sound plausibly competent. You can see why he was able to maneuver his way into people’s lives. He’s an upbeat, friendly guy who believes in you and your value. The money manipulations start as early as their first session. But for someone like Marty, who was prone to shut down at the hint of conflict, Ike’s life coach positivity and promise of “I’m gonna help you and everything’s gonna be all right” feels like a lifeline.

The way Ike silkily asserts control over Marty’s life, and why Marty was susceptible to it, is a key element to all of this. But the show’s approach is weirdly miscalculated. When Ike convinces Marty that the house in the Hamptons needs a brighter coat of paint, we’re treated to a bromance montage of them horsing around, paintbrushes in hand, to the 1988 pop song “Waiting For a Star to Fall” as if we were suddenly transported to an ‘80s rom-com — or more precisely, an Adam McKay-esque comedy spoofing an ‘80s rom-com. There’s absolutely a seduction going on here, but this scene treats these two characters as a joke, one guy literally bopping the other in the nuts and … what is going on here? Are we meant to take any of this seriously? It’s hard to know because comic banter is sometimes abruptly folded into moments that should feel more alarming.