The majority of "possession" cases can easily be concluded as mental illnesses or disorders in behavior. These issues can easily be solved in dedicated therapy or prescribed medication if you just seek out the help that the "possessed" person needs.
Religion is good. Religion is a blessing to this world but when it places a human at risk of serious health issues or even death, it should not be allowed. No matter how you slice it, exorcisms are unhealthy because they place the bodies of "the possessed" under incredible stress that can easily result in death. No exorcisms should be performed if these are the risks.
Seeing as how the problems involved with those deemed "possessed" can be resolved with no harm to the human involved and treatment can be accessed under simple circumstances, exorcisms should be made illegal entirely.
Even leaders in the Vatican agree that it is a barbaric and outdated practice. This is just another example of the religious fairy tale beliefs that have humanity duped into thinking any of it is real. Let alone coercing followers to buy into such harm. Priests have been convicted of homicide for performing exorcisms resulting in death! Professionally "trained" exorcist? C'mon, really? That's like saying I'm professional trained in blowing houses down that pigs live in!
Exorcism is a barbaric ritual that is rooted in the dark times of human history. As with religion in general, exorcism serves no genuine purpose and is nothing more than ritual hocus pocus that never actually solves anything. It should be banned as soon as possible for safety concerns, among other reasons.
Exorcism used in the right hands of a religious leader can often drive demons out of a human. If you ban this practice, some demon possessed people will have no way of getting rid of their demons. Many times also it's a mental problem that can be healed by the placebo effect. A priest comes in and exorcises the demons out of the person, they believe and no longer act like demons are in their soul. This is a religious practice and freedom of religion is very important.
Exorcism serves an important purpose in the world: relieving those afflicted by demonic possession. The devil and all of his fallen angels exist, and they prowl about the world seeking those whom they may devour. Not just anyone can perform an exorcism of course; the Catholic Church asks those who believe they are possessed to receive extensive psychological and medical testing first to ensure they are not troubled by a more physical malady. Only then will she consent to have a professionally trained exorcist examine the patient. Even if one is an atheist and doesn't believe Christianity is not true, what is the harm that could result in an exorcism?