Stephen Lewis, PhD, of the University of Guelph in Ontario, and colleagues conducted a study where they used certain keywords as search options on YouTube.

Surprisingly, there were no warnings related to content or even viewing restrictions. Researchers said that these videos can have a negative impact on young minds.
They wrote, "The nature of nonsuicidal self-injury videos on YouTube may foster normalization of nonsuicidal self-injury and may reinforce the behavior through regular viewing of nonsuicidal self-injury-themed videos."
80% of the videos did not have any viewing instructions. Close to 42% of videos maintained a neutral message , 23% gave a mixed message, 26% completely discouraged such practices, and 7% encouraged the acts.
Source-Medindia