There's no possession, demonic or not, involved in automatic writing. I guess, those who claim to have experienced automatic writing just made it up. It is easy to fake automatic writing. One just have to pretend to be in trance or to be possessed by an entity. This is, of course, very easy to do. This is just an act, nothing more.

Automatic writing is a form of demonic possession. Only evil spirits take control of people's body. If these entities are good at all, they shouldn't have used the bodies as their instrument to make themselves known. And why would they want themselves to be known in the first place? Probably, to incite fear among people. They're probably envious of human existence that they want to possess our bodies. But because they're not too strong to do it, they resort to temporary possession and make themselves known through writing.

I don't believe that automatic writing is a form of demonic possession. I guess, automatic writing still involves possession, but it is not done by demons but by good spirits. Most of these spiritual entities possess people because they want to give message of warning for the bad things to come. These entities just want to help humans prepare for catastrophes. Some people think they're demons because movies show that only bad spirits and demons possess people's body. I guess, it's only the influence of the works of fiction and movies that made us think that all entities that possess people are evil.

There are many people who claim that automatic writing is a form of demonic possession. There's actually a basis for people to say such a thing. The symptoms of demonic possession is actually exhibited during the act of automatic writing. One of these is the sudden knowledge of another language. Some people who are possessed by demons speak in a language they are not familiar with. In automatic writing, this also happens. According to witnesses, some people who do automatic writing scribble words in languages they have no prior knowledge of. Another manifestation of demonic possession is that the subject has no control over his or her actions. Someone takes over the body of the subject, and when the subject regains consciousness, he or she couldn't remember what happened. These are just some of the many things that make automatic writing and spirit possession the same.