They are hypothetical situations, but you are using them to support your point. To knock down that point, I am also taking down your examples.

Where's your proof that some people classified as psychotic are demonically possessed? If you can show me that, then I'll agree with you. Otherwise, this hypothetical situation doesn't matter because it doesn't happen.

The first good argument that an atheist can be terrified by demonic possession. An atheist can not logically be terrified by demonic possession, but can be illogically due to a phobia. Being terrified doesn't have to have a rational causation. I'm irrationally and deathly afraid of heights; even walking down stairs without banisters makes me a 5 (on a scale of 1-10) on being afraid of falling down to my peril. There is no reason for me to be terrified of heights (I usually have no contact with them) and nothing bad has ever happened to me due to heights. In recap, atheists can be illogically terrified by demonic possession; my hat is off to you my dear sir.

(If anyone is actually wondering, I was really on the no side until I started explaining Psychology to someone which made me realize phobias gives the win to the yes side. As for continuing to argue for the no side, the yes side seems to have a lot of bad arguments.)

Being afraid is different from being terrified. See my other post for details.

Really, you feel an intense fear and great anxiety when thinking about that? Being terrified isn't thinking of something as scary. Being terrified means you feel as if you are at gun point (intensely afraid with great anxiety).

When someone isn't one hundred percent sure of the existence of God, he or she is Agnostic. A Christian who has doubts would be considered philosophically to be Agnostic, but in practice may still be a Christian because he or she might still be obeying and practice the Christian religion. However, Atheists have no dogma, only the view that there is no God; the same goes for Agnostics in regard to having no dogma. So even if a person says they are Atheist, but believes there could be a God, that doesn't mean the person is really an Atheist. Just like me calling my car a "rocket ship" doesn't make it a "rocket ship". It is still a car.

When I said, "(Though it is probable to happen in certain circumstances, that doesn't mean there has to be a fear of it happening in every situation available)," I meant that there is always the possibility of people dropping dead in the streets, albeit a slim one, but that doesn't mean one has to be afraid. For example, there is a small probability of a chemical attack, but that doesn't mean I have to be afraid of people dropping dead from chemical warfare in the streets. If it did happen, I would be scared, but it isn't happening and the probability of it occurring is small.

We do know the causes of "psychotic" people; have you ever heard of the Diagnostic and Statistical Manual of Mental Disorders? Many studies have been done, are being done, and will be done on the reasons people become "psychotic". Demonic possession has NEVER EVER been cited as a valid reason by those in the field of Psychology that a "psychotic" person is "psychotic". So being afraid of a "psychotic" person does not mean one is afraid of demonic possession; one being afraid of a "psychotic" person is in fact afraid of severe mental problems. If saying anything is idiocy, it would be saying that we live in a world of magic, dragons, and witches where demons possess the mentally ill and Santa really does bring gifts to the good children.

I never said anything about a disbelief in ghosts. Demons are not ghosts.

No, because if there is no belief in demonic possession, then there is no reason to have a fear of it. Are people afraid of the cessation of gravity? No, because there is no belief in that happening.

Monsters are a great example. Little children are afraid of monsters because they believe in them while adults are not because they don't believe in monsters.

To say that an atheist is terrified by demonic possession would in fact suggest that the person is really not an atheist after all since he or she would have to believe in demons which is a belief in some type of powerful beings in the afterlife. Of course, atheists don't believe in powerful, supernatural beings. If a catholic said that they don't believe God exists, is that person still a catholic?

While it is true that you don't need to know what causes something in order to be afraid of it, that is irrelevant here. Atheists don't believe that demonic possession happens. In other words, their is no demonic possession to them so saying that they can fear the cause of it, doesn't make sense.

Your example has this same faulty logic; people don't start dropping dead in the streets therefore it doesn't matter what would cause it. Being afraid of something has to have a probability of it happening. (Though it is probable to happen in certain circumstances, that doesn't mean there has to be a fear of it happening in every situation available) Why would an atheist be afraid of something if he or she doesn't believe it will happen? Are you afraid of gravity ceasing to exist and then floating off into space? I don't think so.

There is proof that secondhand smoke impacts health negatively for bystanders. Here is a bibliography of the studies that show this: http://www.no-smoke.org/pdf/SHSBibliography.pdf