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Etiology for Pediatric Schizophrenia

Genetics Researchers have found that Schizophrenia is a heritable disorder. Children who have a first-degree family member with Schizophrenia are 5.9% more likely to also develop the disorder compared to children who don't have an immediate family member with the disorder, their likelihood of being diagnosed with the disorder is around 0.5%. Families can use this information to determine the likelihood that their child develops the disorder. If a mother does not have Schizophrenia and her brother or father had the disorder, assuming her husband has no family history of Schizophrenia, the likelihood that their child has the disorder can be anywhere from 2-3%. However, if the mother did have Schizophrenia the child's changes increase by 7%. In addition, if the husband and wife both have Schizophrenia the possibility of their child having the disorder increases to 27%. The study of monozygotic and dizygotic twins provides additional affirmation for the role of genetics. If twins are monozygotic there is 55.8% that both will have Schizophrenia symptoms; [that] probability drops to around 13.5% among dizygotic twins, . Researchers have also been able to identify several genes that play a role in the development of Pediatric Schizophrenia. First is the Catechol-O-methyl_transferase (COMT) gene. The COMT gene produces an enzyme that regulates dopamine in several brain ares. It increases dopamine in areas responsible for positive symptoms and then diminishes dopamine release in brain regions responsible for negative symptoms, . The COMT gene is also an important factor in Schizophrenia because it is connected to the chromosome 22q11.2 that makes the proteins for S-COMT and MB-COMT. MB-COMT helps to metabolize dopamine. On the region of this chromosome also exists a micro deletion syndrome otherwise called velocardiofacial syndrome (VCFS). VCFS is important in psychology because it is linked to other disorders like anxiety, mood disorders, etc. Individuals with VCFS generally suffer from psychosis,. Second, children with Schizophrenia can show abnormalities or mutations in some of their genes. It has recently been discovered that 10-30% of children with the specific abnormality known as 22q11 deletion syndrome tend to develop Schizophrenia or other psychotic disorders.

Brain Abnormalities The National Institute of Mental Health (NIMH) found that children with Schizophrenia showed most of the same brain abnormalities as adults. This was an important discovery because it showed researchers and doctors that youth-onset and adult on-set Schizophrenia reflect the same underlying disorder, . More specifically, children with the disorder have ventricular enlargement, reductions in hippocampus and amygdala volumes, there's also a decrease in the volume of the parietal lobe by 8.5%, the frontal lobe by 11%, and temporal lobe by 8%. Second, researchers found that the abnormalities tend to occur early on in the development of the disorder. Third children with Schizophrenia showed a dramatic reduction in grey matter in their brain which researchers have found to correspond with the on-set of psychosis, . Due to the extensive loss of grey matter, children with the disorder tend to have a mean IQ score approximately two thirds of a standard deviation below average.

Neural Pathways The limbic system is an important factor in schizophrenia. The limbic system is known as the emotional brain. It functions to keep people alive and in touch with our sense of self. It also mediates physiological, behavioral and psychological responses. It also plays a role in how we perceive the environment. Studies have been conducted that looked at the amygdala and the hippocampus in the limbic system. Researchers did find that individuals with schizophrenia have a higher mass of intercranial volume, which could reflect on other important brain changes. Individuals with schizophrenia will have a reduction in their hippocampus by adulthood. The abnormalities in the limbic system are highly correlated with the positive symptoms of schizophrenia .

Environmental Risks There are several early environmental risk factors that can contribute to the development of Schizophrenia. This are; in-utero maternal stress, exposure to disease, season of birth and pre- or perinatal complications, . Research has also shown that major life events can trigger the on-set of Schizophrenia if the child is predisposed to the disorder.

Cannabis Use Researchers found in a large sample study of Swedish adolescents, that there is a direct relationship between early cannabis use and Schizophrenia five years later. However, researchers were not able tell whether marijuana caused later psychosis, whether prodromal symptoms led adolescents to use marijuana, or whether a third factor (such as impassivity) might contribute to both marijuana use and Schizophrenia . After further research, it was concluded that cannabis alone was not sufficient to cause Schizophrenia; it only led to the disorder if the adolescent was already genetically at risk as a child.