When Jonathan Moult and Jonathan Coppin retired from their top partnership roles in their mid-40s, many of their peers were shocked. Both were at the peak of their careers and were earning well at top-tier firms.

But looking back now, with the benefit of psychology training, they each see their departures as entirely predictable. Burnout in law is common, especially at certain points in a career. They were no different.

Now they see that all too often from the other side. Both Moult and Coppin retrained as psychotherapists and for the last decade have run London clinics with a particular focus on lawyers.

They say the many cases they have experienced have remarkable similarities, which are simply predictable responses to consistent levels of stress experienced in top-tier commercial law.

It is common for lawyers to find themselves in a mindset where they feel trapped, for example. The problem is particularly common among older lawyers, who may start to feel like they have not made a good use of their life.

Other common feelings include a strong sense of grievance, the pair say, where lawyers might feel they are being short-changed, or feel unappreciated at home. And it can be common to see lawyers lash out in response to being put under a lot of stress.

A lot of the psychological experiences people worry about are quite normal responses to what they're doing and the environment they're in, says Coppin, who was head of corporate work at Hogan & Hartson (now Hogan Lovells) until 2007 and also spent four years as a partner at Shearman & Sterling in London. "In places like [London], a lot of people will be experiencing things like anxiety a lot of the time and if it's habitual and chronic it will start to have a negative impact."

Many firms' mental health efforts only touch at the edges of such problems though, says Moult, who was Asia head of banking and finance at Herbert Smith (now Herbert Smith Freehills) and a partner at Simmons & Simmons in Hong Kong until 2006.

As such, the pair have now joined forces to come up with a service that they believe could make a fundamental difference to the state of lawyers' mental health. What they are proposing is a series of seven psychotherapy sessions for every lawyer in any given firm at key points in their career.

The first point would be at three to four years' post-qualified, which is usually when the pair have found anxiety has started to kick in for lawyers; then at 10 years' qualified when the strain of making or not making partner is taking hold; and then again at 20 years' qualified when it is common for partners to plateau and feel they have wasted their lives, while also dealing with problems in their private lives.

Making the sessions standard practice for all lawyers, except if they choose to opt out, is key, the duo believe. Moult says most firms only deal with serious mental health issues after they have already emerged. "What we are trying to do," he adds, "is proactive and preventative."

Coppin explains: "Nothing that has been done so far feels to us like it has been making a difference. There is a lot of mood music and picking up the pieces if people get into trouble. We thought: how would you do it so people wouldn't have to make themselves vulnerable? The key is to stop people having to self-select.

"It is completely predictable that someone put in that situation would feel grievance. Predictable, but not always rational. If you talk to people about why they are feeling that way, maybe they can come to the conclusion that, taking everything into account, this is actually working for them – it's actually quite a good deal."

The pair have started approaching law firms about the idea, but believe it could be difficult to get them to sign up as it would be more costly than what firms currently offer.

"It's clear that cash is tight," Coppin says. "Law firms are very profitable but very competitive businesses and they would like to see proven results, and that's not something we can show them. We feel retention and productivity would be better but we can't prove it."

The pair's solution comes with some of the most direct costs to law firms of any of the solutions the industry has implemented. Most employee assistance programmes, for example, are done through insurance plans. This would be a step further. The problem with selling an expensive product to clients without being able to demonstrate any evidence of its success is not lost on the pair. But in spite of acting as therapists to lawyers for many years, perhaps their strongest argument simply comes down to the fact that both believe it would have made a difference to them.

Commenting on his own decision to quit law, Moult adds: "I felt I'd done it all. There was nothing on my list of benefits and my list of costs was as long as my arm. I thought I don't really fancy doing this for much longer. Now I realise that was a bit of a sledgehammer to crack a nut.

"I would have really wanted to have known this stuff."