From the Lubavitcher Rebbe, Likkutei Sichos volume 34, page 336 – Kislev 29, 5739…
It surprises me that I have yet to receive any news regarding any actions taken concerning the “healings” of yoga, the gurus, and all that is related thereto, [particularly] after you notified me some time ago that you spoke about this matter or conveyed it to Profession (name ommitted). Surely you are aware that this scourge (plague, bad thing) is spreading: the event in Safed, the letter of the Sephardic Chief Rabbi, and more.
From the Lubavitcher Rebbe, Sichos Kodesh 5739 volume 3, page 314.
Though essentially positive, meditation can also be used in a destructive manner. These are those who have connected meditation to actually bowing down to an idol, or to a man, or worshipping it or him, offering incense before them, and so on.
These cults have spread throughout the United States and throughout Eretz Yisroel as well. Some of these cults have been called by a refined name, “transcendental meditation,” thereby implying that it is something above our limited intellect.
However, they have also incorporated into their practices the offering of incense and other actions that clearly come under the heading of idolatry.
Since we are living in the darkness of Exile, many Jewish youth have fallen into this snare… Since the idolatry aspects are not publicized, there are those have not raised their voices in protest.
Moreover, they are unsure if such a protest would be met with success, and since no one has asked for their opinion they think to themselves, “Why protest and enmesh oneself in a questionable situation?”
However, while those who should be protesting remain silent, Jewish youth are becoming involved in idolatry, a sin so severe that the Torah declares that one should sacrifice his life rather than worship idols. Moreover, this scourge is spreading, ensnaring youth and adults alike.
Additionally, since “One sin leads to another”, even those who are not yet involved in the more severe and more clearly idolatrous forms of this group will eventually be drawn into this aspect of idolatry in their search of a “holier” and more “sacred” guru-deity.