I was hoping you were still monitoring this place. You have raised some interesting points and I will comment as best I can.
1- DXM is contraindicated for MAOIs and SSRIs, I know, but I haven't run across any claims of problems with sinemet, etc.

The studies in the 90s were inconclusive with good reason. They did not realize that they were dealing with a "bi-phasic" drug which had different effects at different dosages.

2- The relevance of the Indian paper is not the dosages per se, but rather the bi-phasic nature of its action. Without knowing that it is going to be very hard to make sense of any data, particularly when the variance of metabolic rate is factored in. One person takes "X" mg and does great. A second PWP takes the same dose and slips into a major Off as it slips into the serotonin phase.

3- I am familiar with Dr. Hong's work and, in fact, he is one of my "gurus". I particularly subscribe to the neuroinflammatory hypothesis and microglial activation' role. In this case, however, I think we are looking at a different effect of DXM. The LDN approach is based on the interaction with opioid receptors. The blocking of microglial action comes from a second action. Boosting BBB integrity probably comes from a third. And this experience that I am having comes from a fourth as described in the Indian paper and presumably involves the NMDA receptor antagonism.

In my case, I am well within the Low Dose range (about 4 mg per day) but that is due to my slow metabolism's special requirements. Someone else will have to determine the parameters of a normal PWP.

I am sure there are problems. I have already solved a few. But I have experienced a TEN-FOLD improvement. I don't mean to shout, but I am frankly staggered by this.

Now, a quick update, after deciing that the theanine alone was not working for me, I returned to DXM this morning with a single 4 mg dose with my first meds. Two weeks ago I would have been on a two-hour leash. Today the leash ran out at five and one-half hours.