Poltergeists are probably more well-known than any other form of paranormal entity.

While there are cases that are contrary, for the most part poltergeists are considered to be harmless.  They are best known for moving or actually throwing small objects as well as occasionally hiding things from their living owners.  They get their name (poltergeist is loosely translated to mean noisy ghost in German) from the fact that their most common manifestation is loud banging or rapping on walls and ceilings.

Although I still discuss them here as paranormal entities, in reality that idea has been reconsidered and many investigators have actually discarded it entirely.

At some point it became clear that poltergeist activity centered on an individual rather than a location.  Furthermore the individual was almost always a young girl or teenager who would probably now be considered ADD, or ADHD but in the past was called high strung. 
 
Once it became clear that those factors weren’t just “Usually” but in virtually every case the prevailing theory shifted from ghost to something else altogether.

It became a more common belief that the victims themselves were emitting high levels of kinetic energy which was in turn causing the activity.  Basically a young person under the stresses of puberty and other factors was unconsciously, through telekinesis, causing what had previously been considered ghost related activity.

There are certainly many factors that point to this theory being correct.

One thing that had been somewhat puzzling all along was the lack of visual manifestations, and that could certainly be explained this way.

Also the fact that the individual is both victim and perpetrator might explain why this activity usually ceases when the individual is no longer present at the location, or that the activity tends to follow that individual when they leave. 
 
Like everything else however, there are flip sides to both of those points, for example;

If the stressed teenager theory is the actual cause of these cases, shouldn’t there be more of them? In fact shouldn’t they be on the rise?

Although the majority of poltergeist cases are without what are generally considered ghostly manifestations, they are definitely present in some.  Some of the most famous“Poltergeist” cases of all include a component of interaction.  One of the fascinating elements of the well-known and thoroughly researched Borley Rectory case in Great Britain was communication with the entity through ghost writing.

There may be no way to prove or disprove the cause of that communication, but it certainly wasn’t the angst of a teenager.

Also one would ask why, if many living individuals are capable of telekinetically moving objects, can’t a spirit or ghost have the same ability? 

In the end it’s only true to say that while the jury is still out, most investigators and researchers consider poltergeist activity to be a paranormal anomaly rather than a true haunting.

For an excellent example of the contradictions involved in these cases, check the case of the Bell Witch in Tennessee.  The Bell Witch was the basis of the horror movie “An American Haunting” and has many of the elements that discussed above.