Schizophrenia is not one disorder, but a group of disorders affecting approximately 2.2 million Americans, as noted in 2010 by the National Institute of Mental Health. According to the American Psychiatric Association, in order for a patient to be diagnosed with this type of disorder, he must have deteriorated functions in everyday life and experience hallucinations, delusions, or thought disorders.
Genetics
Schizophrenia tends to run in families, as evidenced in a review article published in the journal "Neuron" in November 1997. Furthermore, even when the relatives of the schizophrenic patient do not have this disorder, they still oftentimes have minor brain damage that is typical for schizophrenic patients, as shown by Dr. Kinney in a study published in the "Achives of General Psychiatry" in 1986. Such brain damage includes overall size of the brain that appears to be smaller in both schizophrenics and their relatives.
Stress
Stress may not be the cause of schizophrenia, but seems to aggravate the condition. Dr. Rabkin, on the other hand, reported in a study published in 1980 in "Psychological Bulletin" that the schizophrenics were only slightly more likely than healthy people to report stressful life events during the months prior to the onset of schizophrenia than healthy controls, and concluded that stress may cause this illness to start earlier, but does not cause it.
Viruses
Some scientists have speculated that a virus contracted by the mother during the second trimester when the brain is developing most rapidly could cause schizophrenia. This idea is expressed in an article published in 2003 in "Schizophrenia Research" by Dr. Conejero-Goldberg, as he notes that mothers who have been exposed to respiratory viruses during pregnancy are more likely to give birth to a child that will later be diagnosed with schizophrenia. Yet, noone has been able to isolate this "schizophrenia virus" and the results are not clear.
Biochemical Causes of Schizophrenia
Mainly two neurotransmitters have been linked to schizophrenia: dopamine and glutamine. Dopamine is a messenger that is associated with reward, and many drugs and alcohol increase its production. It was first believed, that there is an excessive amount of dopamine in schizophrenics, but it seems to be a substantial increase in the number of dopamine receptors that is linked to this illness. Receptors are the part of the nervous system that responds to certain neurotransmitters. Glutamate is a neurotransmitter that has been linked to learning and memory. It has been reported that schizophrenics have reduced levels of glutamate when compared to healthy controls.
Age of the Father
According to the "American Journal of Psychiatry," the risk for schizophrenia increases as the father gets older. DNA damage in sperm could explain 15 to 25 percent of all cases of schizophrenia. The risk of bearing a child with this condition doubles when the father is in his 40's and triples when he is in his 50's. However, the risk of having a child with schizophrenia is still only approximately 3 percent, even when the father is 50. Thus, the age of the father is not among the most important causes of this condition.
References
- "Diagnostic and Statistical Manual of Mental Disorders"; American Psychiatric Association; 1980
- "Achives of General Psychiatry" Journal; Neurologic abnormalities in schizophrenic patients and their families.; Kinney, vol. 43, 665-668, 1986
- "Psychological Bulletin" journal; Stressful life events and schizophrenia: A review of the research literature; Rabkin; vol. 87, 408-425, 1980
- "Schizophrenia Research"; Herpesviruses and toxoplasm.; Conejero; vol 60, 65-9, 2003
- "Neuroscience Letter"; Low cerebrospinal fluid glutamate in schizophrenic patients and a new hypothesis on schizophrenia.; Kim, Kornhuber, Schmid-Burgk; vol. 20, 379-382, 1980
