Mention the word “psychotherapy” and you probably imagine a couch, bookshelves full of Freud and Jung, and a therapist in a leather armchair. But what about a therapist in trainers, dispensing advice as he or she hikes around the local park with a client.

And yet this is what one New York therapist does, and it's a method that could have significant benefits here, say mental health experts. It is also a method with an impeccable pedigree: Sigmund Freud, the grandfather of the talking cure, pioneered it when he conducted a “walking analysis” of Max Eitingon, the physician, on their regular walks around the Ringstrasse Park in central Vienna.

A century on, and Clay Cockrell, 37, a social worker and psychologist, is running what he describes as a “dynamic”, cognitive behavioural therapy (CBT) practice from his office in downtown Manhattan. Having started a traditional, consulting room-based New York practice in 1997, he stumbled on the open-air approach by accident.

“Three years ago I was working with a Wall Street client who led an incredibly busy life and was having a difficult time getting off work in the middle of the day. So I said to him: ‘It's springtime, beautiful weather, I'll meet you.' We met near Battery Park and we walked. It was dynamic; he became more focused, more energetic, more hopeful. I started offering it to other clients, and it took off.” Now, he says, his entire practice - 40 clients a week, at $150 (£75) a session - is outdoors.

Cockrell sees most of these clients in Battery Park, Riverside Park or Central Park, and says that he has developed a “really good” inner clock. “The sessions last the standard 50 minutes, but I'm pretty good at timing my walk. I do have a wristwatch, but I try not to look at it as I think it's rude when a therapist looks at his watch. So I've developed a few paths and generally know how long they will take.”

However, there can be exceptions, especially when clients are upset and walk quickly, disrupting his timing. Sometimes the opposite happens. “When poignant things come up or if one of us wants to make a point, we will stop and sit on a bench. Take a moment before moving on,” he says. Cockrell claims that his approach works best with men. “They have a much more difficult time talking about intimate things than women. But when you're walking side by side, it's just two guys walking through the park. You don't have to sit and make this deep dark confession into the eyes of another human being.” The only downside, he says, is when poor weather forces a return to the consulting room, something all his clients are reluctant to do. “I try to avoid that wherever possible. It becomes a different dynamic; the rhythm of the conversation changes.”

A country-side stroll is a mood lifter

Mind, the mental health charity, also agrees with the health benefits of being outdoors, stressing last year the need for “ecotherapy”, or “green” exercise. Its research indicated that 71 per cent of people suffering from depression reported a lifting of their mood after a walk through a park or the countryside, while 22 per cent felt their depression worsen after a stroll through an indoor shopping centre.

Clearly, Cockrell's approach is one that appears to suit solution-focused therapies such as CBT - where practitioners sometimes take clients outside the consulting room to confront their fears - than it does psychoanalytic therapies, with their insistence on privacy and quiet. These factors, says Brett Kahr, a British psychotherapist and author of Sex and The Psyche, are why he would not adopt such an approach.

“Because the kind of psychotherapy I practise is private, patients know that they can say anything and that it will never leave the room. And it's often in the room that stories of abuse, marital breakdown...whatever...can emerge. If I were to take patients on a walk, I would worry about confidentiality and about the intensity of concentration that you would lose.”

And yet Kahr adds that he once supervised a trainee psychotherapist who took a schizophrenic patient on weekly walks around Hampstead Heath. “They had some very touching conversations, so I'd like to remain open-minded.”

Going outside may be an avoidance tactic

Phillip Hodson, a psychotherapist in London, also believes that “whatever works” is valid. “I often work with creative performers, for example, and if a concert pianist wants to get up and play the piano in my consulting room to illustrate something, am I going to tell him to stop? Of course not. I'm going to sit and listen.”

But he points out that a client's desire to move outside may be driven by wanting to avoid a difficult issue. “A client once asked if we could go for a walk, and I said no. What needed to be talked about outside that couldn't be talked about in the room?”

Diana Symonds, 34, a legal recruitment consultant, came to see Cockrell suffering from anxiety about a career change and “residual childhood issues”. She likes his approach as she doesn't have “to sit around in a dreary office on a couch with no padding, feeling like I'm sitting on the previous patient's dirty clothes. What's more, he offers concrete advice, which I like. I didn't want someone just to listen, I wanted help taking action.”

As for confidentiality, Symonds says that it's the norm in New York to talk about all topics out in the open. “Anyway, whenever we get too close to people, we go quiet while we move past them. I've never felt uncomfortable. Plus, I like the exercise.” Surely it's only a matter of time before we see therapists on the march across Hampstead Heath.

For more information on outdoor counselling sessions, log on to www.walkandtalk.com

To find out more about Phillip Hodson, www.philliphodson.co.uk; and Brett Kahr, www.brettkahr.com