Very true...  one can't help noticing that all the "research" into this seems to be conducted by people who are selling something, and stand to gain financially from the "conclusions"

I'm reminded of Mozart's patron when aged 8, Anton Mesmer - who commissioned BASTIEN & BASTIENNE.  Mesmer (who entered the dictionary as the inventor of "Mesmerism", and derivatives such as "mesmerised") claimed to be able to cure major debilitating illnesses (including blindness) with his "hypnotic therapies".  When his attempted cure of the wunderkind pianist Mme Paradis resulted in her permanent blindness, he was chased out of Vienna.  His promises to fund Mozart's Grand Tour of Europe were never honoured.

After having worn out his welcome in Vienna, Mesmer traveled to Paris in 1781, where he became very popular among the upper classes and members of the French court. Mesmer held special salons with dim lighting and soft music. Mesmer would move around the room and use his hands to channel invisible magnetic fluids to his followers. The combination of light, music, and incantations from Mesmer produced a form of hypnotism or "mesmerism."