Woebot: AI for mental health

Andrew Ng
3 min readOct 18, 2017


Dear friends,

I’m thrilled to announce I am joining Woebot’s board of directors as its Chairman. I will be assisting its CEO, Alison Darcy, and the company in its mission to build a chatbot that will help the millions of people who struggle with their mental health.

With the Woebot team in their San Francisco office

Mental health care is in crisis

Depression is the leading global cause of disability. You probably have friends with depression that don’t talk about it. It is stigmatized, which only deepens their anguish. On US university campuses, about 50% of students report anxiety or depression so severe that they can’t function.

Apart from the human cost, mental health also imposes a huge economic burden. Heart disease costs the US healthcare system $147B annually; mental health costs even more: over $200B.

Finally, there is a global shortage of mental health professionals. Even if you seek help, you might wait weeks to see someone.

Woebot: A chatbot mental health coach

While a software chatbot will never replace a human therapist, Woebot makes it possible to inexpensively deliver counseling to millions. Woebot delivers a mood management program based on Cognitive Behavior Therapy (CBT). A Stanford University randomized controlled trial showed that Woebot reduced symptoms of depression and anxiety in 2 weeks.

Despite the hype about chatbots, there’ve been few breakaway successes. But I think mental health may be “the” killer app for chatbots:

  • If you are feeling depressed at 2am, you may not want to wake up your therapist. But a chatbot is there for you 24/7 and is thrilled to talk to you whenever you need a friendly ear.
  • Woebot is just a piece of software. It’s okay to let him see you on your worst day — it will never judge you.
  • Woebot has already had conversations with more users than a typical therapist will in an entire career. While these conversations are more basic, as it learns from these interactions, it will only get better.

The AI and NLP challenge ahead

Chatbots represent a grand challenge for AI and NLP (natural language processing). When a user laments, “I’m surrounded by people but feel invisible to them all”, how should Woebot respond? If a user says “I’m trying not to use”, can Woebot recognize what this means? What if the user says “😳”?

Working with Alison Darcy (left) and Pamela Fox (right).

AI is the new electricity: even with its current limitations, it is already transforming multiple industries. The transformation of mental health care will help millions of people who struggle with their mental health, sometimes through literal life and death decisions.

Woebot already has fantastic engineering and clinical teams. I’m excited to work with the company to continue building up its NLP team as well as its AI abilities. Just as MOOCs are making high-quality education globally accessible, Woebot will make high-quality mental health coaching globally accessible.



Andrew Ng

AI, Machine Learning, Deep learning, Online Education.