Many people get schizophrenia and personality disorder confused, especially since movies and television shows tend to use the terms interchangeably. Schizophrenia is what is considered a “thought disorder,” which means that disturbances in the thought process drive the illness. Symptoms can be expressed in speech, writing, and orally; most schizophrenics hear voices or have other types of hallucinations. The son of Sam serial killer David Berkowitz claimed to suffer from schizophrenia and blamed his killing spree on his neighbor’s dog, who he claimed was actually Satan, who instructed him to kill.
Multiple personality disorder, more accurately known as dissociative identity disorder (DID), is a completely different disorder that is much more rare than schizophrenia, in fact many mental health professionals doubts its validity. DID, considered an “identity disorder,” is a mental illness where in one person has two or more distinct personalities. One of the main symptoms of DID is a loss of time or memory where in the person with DID cannot remember significant chunks of time in their lives, this is due to the dominance of a different personality during the missing time. One of the Hillside Strangler serial killers, Kenneth Bianchi, faked having DID in order to use the insanity plea during his trial, he was discovered to be a fake and he plead guilty to 5 charges of murder.