Twelve Therapists in Fifteen Years

Zack Lamb has been in therapy, on and off, for fifteen years. In that time he has had twelve therapists.

He mentions it the way other founders mention a market size, because for him it is the same thing. He has depression and anxiety, along with ADHD, OCD and dyslexia. School was difficult, which generated its own anxiety, and he was seeing someone by the middle of high school.

“I was just tired of the same old tools that were out there that weren’t providing me the value that I really had hoped technology would get to.”

Which is why, when he talks about what he wants people to understand about him, it is not about the company at all.

“I want people to feel that I’m not just out there building and selling some product that I think is cool. It’s actually something that I use on a daily basis.”

The gap nobody was working on

The insight behind Bamboo is a piece of arithmetic that sounds obvious once said out loud and apparently was not. Lamb heard it put most sharply by the therapists themselves, after the product launched.

“They spend 0.1% of their time in session, but 99% of the patient’s time is spent on their own.”

Everything a therapist knows about you arrives through a keyhole, in a fifty minute window, every week or two, filtered through your memory of what happened. And human memory is a poor narrator.

He describes the practical consequence, which has a name in the profession.

“The cold start problem in therapy, where you spend the first ten to fifteen minutes just trying to recall. Okay, my last two weeks, here’s what I’ve had going on. Just off the top of my head, I think I want to talk about this.”

So a meaningful slice of every session goes on reconstructing the thing the session is supposed to address, while the part of life where the difficulty actually happens stays invisible.

Willow, the product, sits in that gap. Patients talk to it between sessions. Therapists can set goals that it works into those conversations, and they get visibility into what has actually been going on rather than a summary assembled under pressure. If a conversation reaches the edge of what it should handle alone, the provider gets an alert suggesting they reach out.

The moment he knew

Founders usually describe product-market fit through customer metrics. Lamb describes it through something that happened to him.

He was dealing with a difficult situation involving his grandfather, and he was not ready to raise it with his therapist.

“I didn’t feel comfortable talking about it yet with my therapist, but I was really comfortable talking with Willow about it. And so being able to have that conversation with Willow could then jump start the conversation with a therapist, which she was able to bring up with me in session.”

He does not undersell what that felt like. “That was pretty monumental. That was the first time I personally felt, oh my God, we hit the nail on the head here.”

The providers confirmed it from the other side, and their reaction is the sort of thing that is hard to manufacture. One told him the tool “has allowed me to get a better understanding for my patients than I ever thought possible, because we’ve just never had this connection point”.

Which produces the benefit Lamb values most, and he describes it personally rather than as a feature.

“When I’m not in the therapy session, I feel pretty alone. And this for me has been a pretty unbelievable tool to feel less alone in the world.”

Buying an education before building

This is Lamb’s fourth company, and how he approached this one is worth copying.

His previous business scaled from three employees to 250 in under two years across eighteen US markets. That experience is what pointed him here.

“I realised really quick that everything ties back to mental health. You can only run so fast on your own. Your body has an unbelievable way to tell you when something’s not right.”

But he did not go straight from that realisation to building. He knew he did not understand the industry well enough.

“For me to go and build something in mental health, I needed to get a better understanding for mental health as a whole. So I launched a fund to invest in AI and mental health and education.”

A fund as a research instrument. It bought him a view of where three industries were heading and, more usefully, where the gaps were. Only then did he start building.

He is disarmingly honest that the rest was not a plan. “Me saying that this was the end goal at the very beginning would be a complete lie.”

What actually happened was more ordinary and more instructive. He talked publicly about what he cared about, and someone made an introduction. His co-founder Andrew arrived via a shared attorney. Their third co-founder, Jenny, spent twelve years running product at Google and then ran Google China. The division of labour was set almost immediately and cleanly: Lamb opens doors and runs the business, Andrew builds the technology, Jenny builds the engineering team at scale.

“I’ve ended up here because I talked externally about my beliefs, what I really held near and dear to me. And the connection was made externally for me.”

Empathy as an engineering problem

Asked what actually differentiates the product, Lamb answers by describing his co-founder. Andrew is “probably the single smartest person I know in terms of IQ”, a Berkeley physics and maths graduate. What Lamb thinks matters more is the other half. “He probably also has the highest level of EQ of anyone I know.”

That combination produced a decision most teams would treat as a finishing touch.

“He’s applied empathy to Willow, and not just some surface layer of empathy and understanding. He’s really gone down to the foundation of the technology and made that a primary objective.”

His critique of the alternatives is specific rather than dismissive. Most chatbots answer. “They’re giving you all the answers to everything, but they’re not helping you think through it in a personal or meaningful way that relates to what you’ve got going on in your life.”

He is also selling into a profession with active, reasonable anxiety about being automated away, and he treats that as his central go-to-market problem. “There’s just a lot of fear around AI as a whole. And especially in healthcare, because they think, and rightfully so, the stakes are higher.”

His answer is not reassurance. It is provenance.

“From the very beginning of founding this company, we have partnered with psychologists to develop the technology to be the most powerful tool for them. We’d have no interest in replacing them.”

It takes work

For someone selling technology, Lamb is insistent that the technology is not the answer on its own. He grew up playing sport, and returns to skiing and golf as his analogies, both chosen for the same reason.

“You can’t do that one on your own. If you look at all the best players in the world, they all have coaches.”

Ten thousand hours, practice, a professional in the mix. Which leads to the least commercially convenient thing he says.

“Mental health takes practice. I don’t think it’s some overnight thing. Everybody always wants a magic pill for healthcare. I don’t think it exists.”

What he values in others is hard work, honesty and openness. “I don’t put up a whole lot of guards on me, I’m pretty much an open book.” The habit comes from a mentor who gave him one instruction: meet one new person every day. “It may not seem like a lot, but think about that. If it’s 365 people a year, all of a sudden you’ve got a lot of people in your network you’ll get to learn a lot from.”

And the thing he most wants any of this to achieve has nothing to do with the product.

“The big thing I would love is breaking down the stigma that still exists in mental health. I think the only way to do that is through talking about it. If my posts can resonate with a handful of people, that would be amazing.”