I never really got the hang of meditating, despite receiving training from branches of several international training conglomerates (ISCKON, Art of Living, SRF). But meditation as a practice, in the society I grew in, was hailed as the Godsend ultimate technique of taming your minds, something that will definitely and positively stimulate your brain and make you healthier and more active. I didn't (and don't) understand this stuff so I simply dismissed it as a harmless placebo and went on with it.
But before this I had never even thought of it being potentially harmful, and there were absolutely no warnings circulated about this anywhere - neither by the conglomerates and nor by the indie self-styled "gurus" scattered across India and the world. The fact that this is the first time I'm encountering this notion is quite surprising.