Can meditation be harmful? I often see promotion of the positive benefits of meditation in the media and even in school and government settings.  However, there is evidence meditation is not always beneficial.

https://www.psychologytoday.com/us/blog/the-science-behind-behavior/201604/the-little-known-downsides-mindfulness-practice

Is there much discussion of the possible negative aspects of meditation in Buddism?

For instance, could it leave one susceptible to malicious spirits?
What Buddha recommended was the right concentration (Samma Samadhi) a part of Noble Eightfold Path.
Wrong concentration (Mitya Samadhi) may be harmful.