Before revision: While that 2018 study concludes that negative ion therapy has no measurable therapeutic effects and is pseudoscience, 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 other studies,<ref name="Alexander"> other studies conclude there are beneficial effects on cognition and mood.