Study: AI therapy chatbot reduces depression symptoms by 51% in clinical trial

AI-powered chatbots are emerging as a promising frontier in mental health treatment, potentially transforming how millions access care for common psychological disorders. A groundbreaking study published in The New England Journal of Medicine demonstrates that Therabot, a generative AI chatbot, can significantly reduce symptoms of depression, anxiety, and eating disorders within just eight weeks—addressing both treatment efficacy and the persistent challenges of engagement that plague digital mental health interventions.

The big picture: Dartmouth researchers conducted the first randomized controlled trial showing a generative AI therapy chatbot can effectively treat clinical-level mental health symptoms.

• The study tested Therabot, a large language model fine-tuned by mental health experts, on 210 adults with clinically significant symptoms of depression, anxiety, or eating disorders.
• Participants were divided into a control group of 104 adults and an intervention group of 106 adults who received access to the AI-powered mental health support.

By the numbers: Therabot users experienced substantial symptom reductions across multiple conditions over the eight-week trial period.

• Depression symptoms decreased by 51% among participants with major depressive disorder.
• Those with generalized anxiety disorder saw a 31% reduction in symptoms.
• Participants with eating disorders experienced a 19% decrease in symptoms.

Key details: Therabot is a text-based smartphone application compatible with both iOS and Android devices, powered by a fine-tuned generative large language model.

• The chatbot was trained on mental health conversations created by clinical psychologists and psychiatrists who were part of the research team.
• Participants engaged with the system for an average of more than six hours during the study period.
• Users rated the AI therapy experience as comparable to interactions with human therapists.

Why this matters: Mental health disorders affect a significant portion of the population with limited access to treatment resources.

• An estimated 21 million American adults (8.3%) experienced major depression in 2021, with 280 million people affected worldwide.
• Generalized anxiety disorder impacts 6.8 million American adults, representing 3% of the U.S. population.
• About 28 million Americans (9% of the population) will develop an eating disorder during their lifetime.

The bottom line: While the researchers acknowledge more extensive clinical trials are needed to confirm these promising results, the study suggests fine-tuned generative AI chatbots could provide scalable, personalized mental health interventions to help address the global treatment gap.