This is a problem in the US as well, and Michigan.....
Cognitive disability is not well accommodated in criminal justice systems. Yet, people with cognitive disability are overrepresented in these systems. Unfitness to plead law is one legal mechanism that is purported to assist when a person with a cognitive disability is charged with a crime. The aim of such laws is claimed to be to prevent an individual with a cognitive disability to have to engage in a trial process.
It has been said that unfitness to plead law exists in an effort to ensure the right to a fair trial for people with disability. However, in practice, once an individual is found unfit to plead, they do not get the opportunity to engage with the trial process at all and are not afforded the same rights to due process and procedural fairness. In addition, it is common that once an individual is found unfit to plead, they are detained for longer than they could have been if they were convicted – in some jurisdictions, they can even be held indefinitely.