I think that mind over matter is a very powerful phenomenon. It can work for or against us, of course. I have a few instances to describe:
Many years ago, I had a persistent pain in my throat. I saw my GP, who examined me and he explained that what I described was a very common symptom of stress. He prescribed pain relief but the pain went away almost straight away without swallowing pills. I told myself if it was caused by stress (I was very newly married and a visit by my husband's parents to our new house was pending so, yes I was feeling stressed! 😂) then it was imaginary so I unimagined it!
Over the years I've been affected, occasionally, in various ways by physical symptoms caused by stress. As soon as I realise what's happening, the symptoms go away. Sometimes they are replaced by different symptoms!
Recently, I've had mysterious chest pains and, naturally, consulted my GP. He's been very thorough but has found no physical reason for my trouble. After the second GP visit, he remarked that I did seem very anxious (who wouldn't be?) but bells began to ring and the mystery pains have gone away.
So, mind over matter made me unwell but the same thing fixed me. Powerful stuff.
I acknowledge that mind over matter probably didn't cure the psoriasis that someone's husband had and, anyway, it doesn't really matter if the successful effect of an alternative therapy is real or imagined, if it works I won't knock it.