It was the view of the movie tycoon Sam Goldwyn that anyone who went to a psychiatrist ought to have their head examined. By Goldwyn’s logic, anyone who chooses to watch fictional psychotherapy sessions on television five nights a week for nine weeks in a row must be several books short of a library.

Yet that is what is required by HBO’s In Treatment, an innovative new drama series that “strips”, to use the industry parlance, half-hour sessions between a Maryland psychotherapist, Paul Weston (Gabriel Byrne), and four of his patients across consecutive nights, rounding off the week with Paul’s visit to his own shrink, Gina (Dianne Wiest). In this age of high-concept, all-action Kudos-style TV, where a pause for thought risks a viewer reaching for the remote, In Treatment is doggedly static. You barely leave Paul’s front room in the entire series, yet it is as addictive as a morphine drip.

That’s because, as with real-life psychotherapy, the intrigue lies in what information is being withheld by Paul’s regulars — a hospital worker called Laura (Melissa George), who has developed feelings for him; a bolshy fighter pilot, Alex (Blair Underwood) who dropped his payload on a school in Iraq; Sophie (Mia Wasikowska), a young gymnast feeling suicidal; and Amy and Jake (Embeth Davidtz and Josh Charles), a bickering couple trying to decide whether or not to have an abortion. Paul’s sessions with Gina at the week’s end are some of the most riveting, as he hands over the calm inquisitor’s hat and exposes his own riven psyche.

The series was closely adapted from the Israeli hit Be’ Tipul, which has been one of the country’s most successful and acclaimed dramas in recent years. The American version makes cultural adjustments (Underwood’s swaggering fighter pilot fought in Iraq; Be’ Tipul’s swaggering fighter pilot fought in the Israeli-Palestinian conflict), but the changes are rarely substantive. In fact, often the scripts have been translated from the Hebrew. The human psyche, it turns out, is remarkably transferable.

Rodrigo Garcia is a writer and director who has worked on some of HBO’s biggest hits, including Six Feet Under and The Sopranos. He was given the task of bringing Be’ Tipul to American screens. “They were looking for someone sick enough to want to spend 43 episodes with two people in a room. And they asked me to look at it.” Garcia made five pilot episodes, rather than the usual one, so that HBO executives “could meet every character”. Thereafter, his main creative decision was to leave the template largely as he found it.

“I thought they’d made a lot of good choices. First of all, doing it five nights a week would allow us to follow a group of patients week by week. Second, there is the idea that he has other patients all week, but that these four are the ones with problems that are putting salt in his wounds, these are the ones reflecting problems that he’s going through. Because this is fundamentally the story of his own crisis. It’s not just a series of case studies. It’s centred on the Paul problem.”

Watching psychotherapy night after night could have turned out to be as riveting as watching yoga. What the Israeli series did so well, Garcia noted, was to create tension in a seemingly docile environment. “It’s not a series about people talking about problems in their lives. Everyone is doing transference: Laura is falling in love with Paul, Alex is acting out hostility towards his father on him. Sophie is playing out her parental problems with him. The conflict is in the room. There is a confrontational quality to the relationship of these particular patients with Paul. By bringing the conflict into the room, it feels less talky — it’s not ‘Let me tell you what happened to me’, it’s these two people duking it out.” By making every session a tussle, albeit a mental one, In Treatment manages to mine drama from two people sitting in chairs.

Of course, without jumpcuts, CGI or other distractions, both the acting and the writing have to be first-rate. Because HBO is not beholden to advertiser’s seasons, like many other American networks, they were able to prolong casting until they found the right performers. Evidently, they got it right — Byrne won a Golden Globe for his mesmerically crumbling Paul, while Wiest took home an Emmy for best supporting actress. The second season will see them joined by the British actor John Mahoney, best known as Marty Crane in Frasier, alongside Hope Davies and The Wire’s Glynn Turman. A part in In Treatment is acting distilled to its base elements — you can see why they’ve proved catnip for A-list performers.

“All you’ve got is the words, and what’s underneath the words, and the silences, and what those two people want,” Garcia says. “The acting and writing are everything.”

It was a precondition for both the Israeli and American writers (although not the actors) to have been in therapy themselves (the Israeli team included Ari Folman, who went on to make Waltz with Bashir). Warren Leight, who is overseeing series two, has said that “the first rule of writing for In Treatment is having been in treatment”.

That does raise another spectre for the viewer, though — one of being asphyxiated by wordy introspection or psychobabble, or even of the whole thing descending into parody, like a nine-week-long Woody Allen sketch.

“We wanted it to feel like therapy, but not sound like psychobabble, theories, medical talk,” Garcia says. “It has to have an authenticity — people who are going through therapy are one of the core audiences — but we were interested not so much in the language as the structure: how the session moves, how it is conducted by both the therapist and the patient.

“We draw on some classic therapeutic things — a patient wants to come to therapy to talk about something. Now that they’re here, they do everything that they can not to talk about it. Or people saying I don’t want to, or I shouldn’t really be, or I don’t need to be here. The reluctance to be in therapy is a good point of departure.”

Garcia himself has been in therapy. “I’m not a lifer, but I’ve been for short stints over the years, and found it very useful.” His father is the author Gabriel Garcia Marquez. It feels pleasingly Freudian to ask him what the father thinks of the son’s achievements. “He’s seeing the show right now, because it’s playing in Mexico, where he lives. He loves it. He’s never been to therapy himself — he says that books are his therapy. He would say that, as an artist, he doesn’t want to know where the things come from.”

Whatever In Treatment has to say about modern minds and their distortions, it has as much to say about modern viewing habits. When the first series went out in America, HBO soon discovered that viewers were more interested in some of Paul’s patients than others. Because of the regular screening slots and In Treatment’s structure, it allowed them to record only the characters they liked and watch their individual stories unfurl. In effect, some viewers were making a build-your-own drama. HBO obliged by showing all of the previous episodes about a given character on that character’s night, using Sunday as a catch-up for the whole week.

“A lot of people watch shows when they want,” Garcia says. “On demand or TiVo or online or when the DVD comes out. We didn't set out to get that audience, but I think it’s a happy marriage — it’s a show that lends itself to that. Obviously, by having five patients, some are going to be more liked than others.”

He adds that in America, there was no obvious consensus — everyone had a different favourite. But naturally, having worked his way through 43 episodes of close-quarters psychotherapy, Garcia believes the show is richest if you watch it all. “Paul’s crisis is the centre of it — and you don’t want to miss any part of that.”

In Treatment starts on October 5 at 10pm on Sky Arts 1

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