Why test a chatbot for depression and anxiety?
Cognitive behavioral therapy, or CBT, teaches people to notice unhelpful thoughts and try new ways of responding. It works well for depression and anxiety. But many people cannot get it, and self-help apps that teach CBT are often dropped after a few days.
The researchers wanted to see whether a conversational agent, a program you text with like a messaging app, could make these exercises easier to stick with day to day.
How was the Woebot trial set up?
A Stanford team recruited 70 students aged 18 to 28 online, all of whom said they had symptoms of depression or anxiety. They were randomly split into two groups: 34 used Woebot for 2 weeks (up to 20 sessions), and 36 were sent a free ebook from the National Institute of Mental Health (NIMH) called "Depression in College Students."
Woebot is not generative AI that writes its own answers. It follows a decision tree: scripted conversations with suggested replies and some language processing. Each day it asks how you feel, offers short CBT lessons, and sends mood charts. On day one it explains that it is not a person and not a substitute for professional help. Participants who reported suicidal thoughts were automatically given crisis line numbers and told to call 911 in an emergency.
What did the study find?
Symptoms were measured with standard questionnaires: the PHQ-9 for depression and the GAD-7 for anxiety. After 2 to 3 weeks, depression symptoms fell clearly in the Woebot group but not in the ebook group. The authors describe the effect as moderate (an effect size of 0.44).
For anxiety, there was no difference between groups: both improved in a similar way. People used Woebot a lot, 12.14 times on average over 2 weeks, almost every day. They reported more satisfaction than the ebook group. Some said the bot misunderstood unexpected replies or got stuck in loops.
Key figures
- 70young adults aged 18 to 28 randomized to Woebot or an ebook
- 12.14check-ins with Woebot on average over 2 weeks
- 0.44effect size on depression symptoms, rated moderate
A chatbot is not therapy, and neither is Mima
This trial suggests a chatbot may help some students practice coping skills day to day, over a short time. It is not therapy, and neither is Mima: she does not treat anything and does not replace a professional.
Mima listens without judging and keeps track of your sleep, energy, and mood, so you can talk about them with your doctor in clear words. If you are struggling, reach out to a professional. In an emergency, call or text 988, or call 911.
What does this mean for people who are struggling?
This trial suggests that a well-designed chatbot may help some people practice CBT skills day to day, alongside other support. It does not show that a chatbot can treat depression or replace a therapist, psychiatrist, or doctor.
If you are going through a hard time, talk to a health professional. If you are in crisis or having thoughts of suicide, get help right away: in the US, call or text 988 (Suicide and Crisis Lifeline), or call 911 in an emergency.
What are the limits of this study?
The trial was small (70 people) and short: 2 weeks, with no follow-up to see if the effect lasted. It was not blinded, so participants knew which group they were in. An ebook is a weak comparison, and 17% of participants did not complete the second survey, more often in the ebook group.
Participants were mostly female students from one university community, not patients being treated for depression. Finally, the second author founded the company that created Woebot and has a financial interest in it, and the company paid for participant incentives. The authors themselves call for larger studies with longer follow-up.
Frequently asked questions
Does Woebot work for depression?
In this small trial, depression symptoms dropped more with Woebot than with an ebook after 2 weeks. There was no long-term follow-up, and the results need to be repeated in larger studies.
Is Woebot a replacement for therapy?
No. The bot itself tells users it is not a person and not a substitute for professional help. It was tested as a self-help tool.
Did Woebot reduce anxiety?
Not more than the ebook did. Anxiety dropped by a similar amount in both groups.
What should I do if I am in crisis?
Call or text 988 to reach the Suicide and Crisis Lifeline, or call 911 in an emergency. You can also reach out to your doctor or a mental health professional.
The original study
Fitzpatrick KK, Darcy A, Vierhile M “Delivering Cognitive Behavior Therapy to Young Adults With Symptoms of Depression and Anxiety Using a Fully Automated Conversational Agent (Woebot): A Randomized Controlled Trial.” JMIR Mental Health, June 6, 2017. DOI : 10.2196/mental.7785
Read the full study in JMIR Mental HealthThis article summarizes a scientific study and is not medical advice.