//To avoid adding to my above post a 3rd time...
A caveat or two is warranted.
1. A more intelligent approach would be preceded by a blood test to ascertain if vitamin D levels are insufficient to begin with. I infer mine perhaps were by the positive effects of taking the supplementation.
2. Excess vitamin D intake / supplementation on its own can precipitate tinnitus. As I already have it (the pulsatile / vascular form - no damage to the mechanical apparatus of the ear / ordinary hearing ability), I have little to fear from its sudden appearance.
3. The experiment objectively suggested itself as potentially worth a personal trial, as auditory cortex overactivation is common to both the hearing voices problem and pulsatile tinnitus.
4. In my case, several of the positive effects rapidly diminish when I stop taking the vitamin D3 supplement as follows:
A. tinnitus noise volume goes back up to former distressing levels within 2 days of cessation.
B. Rheumatoid athritis pain resumes its previous severity within 24 hours of cessation.
C. My ability to sleep mostly through the night reduces to former distressing levels again within 48 hours - related to A.
D. Understandably, my cognitive function (memory and attention) resumes its previous impaired level within 2 days of ceasing supplementation - consistent with the effects of A - C.
E. Anecdotal benefits to an individual are inadequate proof of potential benefit to another. I merely mention the above facts as being of potential interest insofar as they have provided a personal improvement to my own mental and physical health.
F. Supplement has only been taken for 16 days in total, excluding 2 days stoppage to determine what, if any, permanent gain had been induced. Again, a blood test would determine if any vitamin D level insufficiency has been remedied. This has not been done.
G. A moderately elevated mood was found to occur within 90 mins of first dose, lasting noticably for more than 4 hours This effect was found in two other individuals known to me, at the same time of onset. While an increased feeling of happiness is generally regarded as positive, the relaxation produced is nonetheless a fresh cause of psychological concern in the case of extreme bradycardia ( as in, '****, I hope this doesnt make my heart stop' (get any slower)).
Edit. Related psychiatry case reports on various conditions being related to vitamin D insufficiency and abated by supplementation can be accessed by the curious via a search like the following:
https://www.google.com/search?q=vitamin+D,+Psychiatry+Case+Reports,+pdf&ie=utf-8&oe=utf-8&client=firefox-b-m
The case which prompted my initial interest may be found here:
https://www.hindawi.com/journals/crips/2020/2046403/