Josh Radnor is talking about alcohol. The actor-director and sitcom star has given it up and is finding life as a former imbiber difficult. “There’s some grief that goes with that change, because alcohol feels so kind of youthful and sexy and romantic,” he sighs, before confessing to a recent lapse in Paris when he indulged in a few glasses of red wine.

On the bright side, there is always ayhuasca, a plant-based Amazonian infusion which is said to have spiritual and healing qualities. Radnor is a big fan, but more of that later.
For the past eight years, the Columbus, Ohio-born star has been building a fan base as the lead character on the Emmy-winning How I Met Your Mother. As the show moves into its eighth and (probably) final season, he has been stretching his creative muscles in other areas, as the writer, director and star of his own films.

“I’m still really interested in being an actor,” he says. However, after almost a decade on the TV show and numerous stage roles, he admits: “I don’t know how hungry I am. If a role doesn’t feel like something that has some urgency to it, I just won’t do it.” With directing, by contrast, he says: “The landscape feels unmapped, largely, and unexplored. And there’s something exciting about that.”

We meet at London’s plush Langham Hotel when Radnor is in town to attend the first Sundance Film Festival to be held in the UK, with his second self-penned directorial offering, Liberal Arts. In it, he plays Jesse, a recently-dumped 35-year-old New Yorker who returns to his alma mater to deliver a speech, and falls for a 19-year-old student (Elizabeth Olsen).

Despite the setting — Radnor chose to shoot at Kenyon College in Ohio, where he himself studied, though the film is not directly autobiographical. But, as with his previous feature, Happythankyoumoreplease, there were “themes which I was wrestling with in my life when I was writing it,” he says. “I had a sense the movie would be about time, about ageing, about change, about nostalgia, about books.”

The subject of change comes up a lot in our conversation. And also, Radnor has realised, in his work. “I think I write about change so much because I know it’s the secret to life. But I also know it’s something I panic about and try to stop because of that grief with letting something go…”

When he says goodbye to How I Met Your Mother, with it will go the structure the show has given his life for almost a decade. He likes structure, and when he finally left academia at the age of 25, after completing a Masters in acting, “it was a shock, the icy cold water of adulthood,” he says. “That was a big transition.”

During his formative years, Judaism was part of the daily framework. His parents weren’t particularly religious, “more culturally American conservative”. They were “very active in the synagogue”, though, and sent him to an Orthodox Hebrew day school for nine years. Connecting the dots of his life, Radnor quotes playwright Tony Kushner’s theory that the reason why so many Jews are attracted to the theatre, is because there is a similarity between reading the Talmud and reading a play.

“What you’re really trying to do when you study the Talmud is get underneath the words. There’s a digging process that goes on. And that’s what you do in a play,” he says. “You’re looking for the subtext. For what’s motivating what’s on top. So I think there is a kind of overlap between my upbringing and what I do.”
Suggesting to him that Jesse’s analytical mind-set in the film feels Jewish, he says that one of the things he has grappled with in Judaism, and in his life generally, is that “there is such an emphasis on the intellectual and on the analytical and on the cerebral, that you’re leaving out the emotional. When I started working as an actor, that’s when I got to strike more of a balance. Liberal Arts is about that kind of treacherous journey from your head to your heart. And I think that’s been a big theme in my life.”

He still has moments when he retreats into his head, for example when he is “fearful or uncomfortable with something… and it’s not a safe neighbourhood, sometimes. You can get all sorts of wacky notions and you end up trying to protect yourself or protect others.”

Something that has helped him open up more is the aforementioned ayhuasca, which he first took six years ago when he was 32. He was going to publish a book based on his experiences taking the brew, which is said to cure everything from depression to cancer, but changed his mind. “I didn’t feel there was a way to put this book out without it being really mishandled in the press,” he explains. Instead, he is pouring what he learned into his work. Thus, in Liberal Arts, it informs a scene where music mellows Jesse’s perception of New York, and his reaction to the slacker wisdom dispensed by Zac Efron’s character, Nat.

Radnor, who does not talk about the subject on record much, says that taking ayhuasca “places you in your heart in a way that is so profound that you realise how deeply locked we are into our heads, and how our minds are our place of judgements, suspicions, defence — where we categorise, we label, and we keep things away from us.

“The experience of working with that medicine is a very unifying one… and very humbling.”