Research and success stories are profound tools when teaching about any topic. They may serve as the motivation for a person to act. But no matter what has been reported by others, it is, of course, personal experience that makes an actual difference in a person’s life. This concept is inherent in all yoga philosophy: belief is not necessary. Become your own experiment and try it for yourself.
This is particularly relevant with mental health concerns since the nature of such issues can easily lead people to think that they are inherently unstable, hopeless or incurable. By sharing research and success stories, you might help to expose such incorrect assumptions, and provide the motivation that prompts students to experiment with practices.
Or a person may try yoga having had no awareness of its track record with mental health, and find that they feel more balanced as a result of yoga practices. This may then prompt them to want to learn and try more.