Alternative Names
Mental illness - schizophrenia
Symptoms & Characteristics
Schizophrenia is a severe, lifelong mental illness. Affected people may have delusions including paranoia or hallucinations. Other common symptoms may include.
- unusual thoughts/perceptions
- problems speaking and expressing emotion
- problems with attention, memory and organization
Symptoms usually appear earlier in affected males than in females (late teens to early 20s as opposed to mid-20s to early 30s).
Treatment
Medications can relieve some symptoms, but it can take many attempts and sometimes, years to find the right medication. With treatment, many people experience improvements.
If someone notices or experiences any of the signs or symptoms common to schizophrenia, it is important to see a doctor immediately.
How Common Is It?
About 2.4 million Americans are believed to be affected with schizophrenia.
Genetics & Inheritance
The causes of schizophrenia are largely unknown. Schizophrenia is most likely a multifactorial condition, which means it involves a combination of genetic, lifestyle and environmental factors.
About 1 in 100 people are believed to be affected with schizophrenia. Studies have demonstrated that when at least one person in a family has schizophrenia the risk to close relatives to also develop schizophrenia is higher than 1%. As such, schizophrenia appears to have a significant genetic component.
Researchers believe that there are probably a number of genes that contribute to the development of schizophrenia as well as affect a person's response to certain schizophrenia medications.
Variations in at least 30 genes have been associated with schizophrenia and susceptibility to schizophrenia in some families.
One particular chromosomal region, 22q11, appears to be associated with schizophrenia. Multiple genes are located within this region. A deletion of this region causes deletion 22q11.2 syndrome, which in addition to schizophrenia, has many other characteristic mental and physical features. Some studies have shown that very small deletions (called microdeletions) within this same region are found more often in people with schizophrenia than in non-affected people. Researchers have therefore suggested that mutations and/or variations within specific genes in this region may contribute to susceptibility to schizophrenia in the general population. Several genes within this region have been implicated. However, studies have been conflicting, and additional research is needed.
Single nucleotide polymorphisms (SNPs) are small variations in a single "letter" of DNA that can be found throughout our entire genetic make-up. Some researchers have proposed that multiple SNPs may influence the risk to develop schizophrenia in some people. For example, one particular SNP has been associated with susceptibility in males, but similar associations were not found in females. How these SNPs contribute to schizophrenia is unclear and much of this research is considered preliminary at this point. In addition, research is currently often limited to specific ethnic groups. Further research is needed to replicate study findings across different ethnic groups.
Other yet to be identified or adequately classified genes may also contribute to schizophrenia.
The estimated recurrence risk for mental illness in a family depends on many factors. These factors may include the number of affected people in the family, the degree of relationship (close, distant) of the affected relatives, as well as the type(s) of mental illness.
Genetic Testing
Clinical genetic testing for schizophrenia is currently unavailable. Research testing may be available for people who are considered at risk. A genetic consultation with a trained genetic professional may be beneficial in discussing the benefits and limitations of genetic testing as well as recurrence risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
Informational genetic testing for susceptibility to schizophrenia is available online (over the internet) as part of a whole genome scan. Whole genome scanning involves analyzing thousands of SNPs at once related to a number of different health conditions.
- At this point, many genetic professionals do not consider this testing clinically useful or medically relevant, but for informational purposes only. Go to the Tests tab to link to the best providers, compare providers and read provider reviews.
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