Before revision: While that 2018 study concludes that negative ion therapy has no measurable therapeutic effects, and it is considered to be pseudoscience by this and other studies, other studies conclude there are beneficial effects on cognition and mood.
After revision: While that 2018 study concludes that negative ion therapy has no measurable therapeutic effects, and it is considered to be pseudoscience by this and previous studies, other studies conclude there are beneficial effects on cognition and mood.