A family history of psychiatric conditions is considered to be the strongest risk factor for schizophrenia among first-degree relatives (8).
The main known risk factors in development of schizophrenia are genetic causes, pregnancy and delivery complications, slow neuromotor development, and deviant cognitive and academic performance.
The gene, called C4 (complement component 4), sits in by far the tallest tower on schizophrenia's genomic “skyline” (see graph below) of more than 100 chromosomal sites harboring known genetic risk for the disorder.
Among these, experts have found genetics to be one of the strongest predictors of whether a person will develop schizophrenia.
Family History and Genetics
Just as with other medical and mental health conditions, genetic predisposition plays a role in whether someone will develop symptoms of schizophrenia. The numbers to support this are strong.
Understanding Prodrome Syndrome, a Precursor to Schizophrenia. “The prodromal syndrome is essentially a syndrome that leads up to the full-blown psychosis,” says Nitin Gogtay, MD, director of the Office of Clinical Research at the National Institute of Mental Health (NIMH).
In most people with schizophrenia, symptoms generally start in the mid- to late 20s, though it can start later, up to the mid-30s. Schizophrenia is considered early onset when it starts before the age of 18. Onset of schizophrenia in children younger than age 13 is extremely rare.
Deletions or duplications of genetic material in any of several chromosomes, which can affect multiple genes, are also thought to increase schizophrenia risk. In particular, a small deletion (microdeletion) in a region of chromosome 22 called 22q11 may be involved in a small percentage of cases of schizophrenia.
People with high IQ scores are less likely to have schizophrenia than the general population. If intelligence is best measured by IQ tests, a 2006 study suggests that those with schizophrenia have overall lower scores than the rest of the population, even before they're diagnosed.
Predictors. Several factors have been associated with a better overall prognosis: Being female, rapid (vs. insidious) onset of symptoms, older age of first episode, predominantly positive (rather than negative) symptoms, presence of mood symptoms, and good pre-illness functioning.
The truth is that while schizophrenia is influenced by genetics, it isn't directly inherited.
3 gene DTNBP1, the human ortholog of the mouse dysbindin gene, is associated with schizophrenia.
If you have a “full” sibling with schizophrenia, you're 10 times more likely to develop it. If both parents have schizophrenia, the chances their child will also have it is about 45 percent. But according to research, about 85 percent of people with schizophrenia don't have a family member with it.
One of the best-known risk factors for schizophrenia is having a family history. In reality, however, 80 percent of people with schizophrenia or bipolar disorder, particularly with psychosis, have no family history at all.
Schizophrenia: More dopamine, more D2 receptors.
Many people with schizophrenia are exceptionally gifted, including Nobel Prize winning mathematician, John Nash, who recently had a movie based on his story called, “A Beautiful Mind.” My mother, who is Chris' sister, can attest to his brilliance, “ He was gifted in so many ways; he was so curious about life and had a ...
Mental disorders are the result of both genetic and environmental factors. There is no single genetic switch that when flipped causes a mental disorder. Consequently, it is difficult for doctors to determine a person's risk of inheriting a mental disorder or passing on the disorder to their children.
Unfortunately, most people with schizophrenia are unaware that their symptoms are warning signs of a mental disorder. Their lives may be unraveling, yet they may believe that their experiences are normal. Or they may feel that they're blessed or cursed with special insights that others can't see.
According to the World Health Organization (WHO), the decline in life expectancy among people with more severe mental illness ranges from 10–25 years . Most studies of schizophrenia show a life expectancy reduction of 10–20 years.
Residual Schizophrenia
This specific type is characterized by when an individual doesn't display positive symptoms of paranoid schizophrenia (hallucinations, delusional thinking), although they still have the negative symptoms or more mild schizophrenia symptoms (no expression of emotions, strange speech).