I don’t think there can be any technological product or mobile application that can help us fight anxiety and depression. In fact, it has a completely opposite effect on our mental health.
Coming to your question, yes there is one app developed in New Zealand by a couple named Matt and Katie Gatt which is said to help people in fighting anxiety. According to the reports, it teaches people how to form happier thought patterns. Further, it matches your subconscious thinking with your goals and ambitions to help you lead a happy life. The app is called Thinkladder and is available on App store.
To me, it is highly doubtful. If you are relying on something which has no life and cannot feel like humans, I don’t think it could be of much help. One cannot even rely on people who are connected to us over whatsapp and Facebook as they are not really with us. Then how can we expect something which can’t have humanly feelings to help us fight with one of the most complex of those feelings?