Exorcism?

[Sheldon]

Jesus christ buy a cookbook for a change.

  if you will just look at the number of Hollywood movies on the subject you can see that the majority of people seem to be interested in these subjects rather than not.

I find scifi movies entertaining, this doesn't make them true or anything in them real. 

  Personally, I choose to leave the subject aside because it’s negative, scary and misleading. 

I see nothing scary here, except how willing intelligent people are to believe in irrational and unevidneced supersition. 

   But this guy is different (I mean Scott Peck). 

If the supersition he is peddling is unsupported by any objective evidence, then no, it's not different. 

When I find people who have intelligent theories on a phenomenon that we all know exists in this world even if there has been no verifiable observation just yet, I tend to read these works.

That seems like an obvious oxymoron, we would only know something exists if there is sufficient verifiable or objective evidence. 

Scott peck is event pointing out to the fact that “possessed” people are usually people who messed with some occult practices at some point in their lives. He also states that true possession is a rather rare phenomenon.

The claim anyone is ever possessed, or that possessions are possible is not a fact, it's a supersitious belief. Since no one has ever demsontrated anything approaching objective evidence that possessions are possible, raring than he thinks I'd bet. 

So if we are to refuse an idea, isn’t it better to first try to understand it correctly?

So I need to become an expert on the Harry Potter novels before I can disbelieve the claim they evidence wizardry? This tire old canard is bread and butter to "snake oil"salesmen. The burden of proof lies with the claim, not with those who disbeliive those claims. What you've asserted there looks suspiciously like an argumentum ad ignorantiam fallacy, and that fallacy is very common in superstitious apologetics. 
Offer the most compelling reason you have, for believing possessions are real, or that they are even possible. Please don't waste my time citing books or authors, you have brought the claims here, so just pick the most compelling reason you gleaned from them.