As a psychotherapist, I share your concerns over how current legislation will allow doctors to effectively jail those deemed likely to commit a crime in the future by virtue of a possible future 'insanity', or to declare 'insane' those whose views did not accord with established thinking.
To address only one of these points, how will judgements be made on the future behaviour of individuals? I assume that psychics will not be employed, so judgements will be based on some form of personality profile - historical knowledge of X's typical behaviour.
This opens up an interesting avenue of thought. In the last 100 years or so, well over 100 million people have been killed in wars. These wars have been fought for all sorts reasons, with which we may agree or disagree, but they were all started by politicians, of varying shades of opinion. In other words, the classification of someone as a 'politician' places them in a high-risk category for humanity as a whole.
Even if one accepts the media's and medical stereotype of the 'mad killer' (and yes, very disturbed people have killed numbers of people), these rare events pall into insignificance compared with the millions killed at the whim of our leaders. Surely, then, someone who claims to be a politician is a statistically significant threat to us all.
If future behaviour is to be based on past experience, then the finger points very clearly at those who profess to be our masters. Will this be recognised? It might be interesting to put these points to those who look after our welfare. - Mike Harding, Chair, The Society for Existential Analysis, London