Without getting into the ins and outs of Tavistock which is its own thing, if you are prescribed *any* medicine off label, you are in the realm of not well understood. No drug gets to market unless it is safe - and this safety level is fairly high in terms of a bar - but equally medicine moves faster than the underlying research. Once a drug is safe, clinicians will use the drugs for other things based on their understanding of the drug, understanding of the disorder they are treating, understanding of the individual they are treating, and the potential dangers which they will monitor and cease treatment immediately for.The short answer is that they are not well understood at a clinical level - according to an independent report
And likely you are taking some medication either off label or that was off label for the use you are taking it for, and is now approved officially for. This is how medicine progresses.