Re: Is there an explanation for abnormal behavior?

Abnormal behavior can be seen in a variety of neuropsychiatric 
disorders.  Schizophrenia is a brain disorder in which people frequently 
hear voices (auditory hallucinations) and respond to these resulting in 
very abnormal behaviors such as talking to themselves.  Dissociative 
Identity disorder (in the past called multiple personality disorder), 
involves people who usually have had traumatic incidents and split off a 
part of their personality such that they take on the appearance of more 
than one personality inhabiting the same body.  The causes of most 
neuropsychiatric disorders are not known but there is good evidence that 
many are the result of a combination of genetics and the environment.  
There is no scientific evidence supporting the belief in possession.


hope this helps,
gabriel vargas md/phd

References:
Sadock and Sadock 7th Edition Comprehensive Textbook of Psychiatry