The exact cause of schizophrenia is unknown, but scientific evidence suggests that paranoid schizophrenia is an organic or medical disorder, not just a psychological malady of the mind. The National Institute of Mental Health reports that 1 percent of the total population is diagnosed with schizophrenia. Paranoid schizophrenia is one of the five types of schizophrenia; the symptoms that distinguish paranoid schizophrenia from the other types are paranoid delusions and beliefs of persecution.
Genetics
The National Institute of Mental Health (NIMH) indicates that schizophrenia is known to run in families with a history of psychiatric disorders. However, this is not always the case. According to the Mayo Clinic and NIMH, evidence from years of research point to genes from first-degree relatives leading to an increased risk of developing schizophrenia. NIMH also points out that ongoing studies are focusing on chemical malfunctions in the brain as keys to the genetic link between relatives and persons with schizophrenia. According to the Mayo Clinic, the scientific community continues to work toward proving that genetics is the primary cause of the disorder.
Brain Chemistry
A 2009 study cited by ScienceDaily.com concluded that certain neural chemicals are impaired in people diagnosed with schizophrenia. The Mayo Clinic also links the neurotransmitters dopamine and glutamate in causing schizophrenia, though research is still ongoing as of 2010 about these connections.
Environmental Contributions
Environmental causes include social and nutritional factors. Schizophrenia.com also notes that certain environmental factors may play a key role in developing the disorder in the early developmental years of life. Such factors include severe physical abuse, neglect of basic needs and potential exposures to viruses. The theory on environmental cause is based on the hypothesis that brain chemicals are altered as a biological response to environmental stressors. Twin studies cited in PlosMedicine.org explore the relevance of prenatal environmental influences compared to adoption studies of environmental influence for siblings that develop the disorder. Based on these studies, paranoid schizophrenia is best described as being caused in part by heredity and in part by environment.
