I am in a field of medicine far removed from psychitric care, but will attempt to answer. I do know that we are trained to accept things that have been well studied and published. I do have a few friends who are psychiatrists (MD/DO) who do believe in MLC and have dealt with it. Some, however, do go strictly by a diagnostic book called DSM 5, and refute anything not addressed there. I do not think MLC is a diagnosis in there.
Psychologists and counselors (PhD or LMSW, etc) are a mixed bag. IMO they tend to get to the root of problems and address them individually. In the case of MLC address childhood trauma and depression separately. My W's counselor told her to do what makes her feel happy and issues will be dealt with down the road. Our kid's counselor believes in MLC and told W to seek more help.
I am trained to take a group of problems and find a common link (cough, fever, chills = pneumonia). On the other hand, a counselor/psychologist would be trained to look at these individually. This is just my guess.
I did believe, as do many of my medical friends. However, it is stigmatized as a man going out and buying a shiny red convertible and running off with a hot blonde with double D's. I had no idea about my W's MLC until I started to piece together all of the elements and researching the stages. This is why most of my medical friends believe--we can trace all of this to one common diagnosis. I think if it were common knowledge that they exhibit behaviors as mentioned on these boards it would be much more understood and accepted by the psychological community.
The colleagues I have confided in all say the same thing......she needs serious psychological help. It's surprising how many of them have known someone in MLC. I think one day it will be officially accepted. It will just take mountains to be moved after decades of little recognition.