Disorders found to commonly appear together.
A breakthrough into the origins of schizophrenia has shown that the disease is, in fact, eight separate kinds of mental illnesses. The causative finding may help improve early detection of the disease, which usually isn’t diagnosed until young adulthood.
A team from the Washington University School of Medicine in St. Louis, Missouri published the study in The American Journal of Psychiatry. The study found that each of the eight distinct mental disorders had its own set of unique symptoms. While distinct, the disorders seem to commonly appear together, which suggestswhy they were never diagnosed until now. The study linked some of the disorders with specific symptoms of schizophrenia such as trouble with socializing, reduced emotionality and activity, or difficulty in recognizing reality.
Each of the identified disorders also has unique genetic origins. The authors found that single gene mutations were only weakly correlated with schizophrenia risk, but groups of related genes mutated together were tightly correlated with development of the disease. Fourty-two of these gene groups were identified, and their mutations increased schizophrenia’s likelihood from 70 to 100 percent.
Schizophrenia has been known to have a genetic basis for years. Previous research had shown that having a family member with the disease increased its likelihood by 10 percent; having an identical twin with it, 40 percent. Many scientists hypothesized that the cause of schizophrenia was 80 percent genetic, but until now they couldn’t say which genes were responsible.
Some of the eight disorders had a greater genetic precedent than others. Still, the authors couldn’t identify the remainders’ likelihood of development with certainty. Like many mental illnesses, an individual’s environment might play a role in development. Stress and substance abuse has been linked to the development of schizophrenia in past research.
The study’s authors hope to use their findings to improve early detection of schizophrenia risk. The disease most commonly develops in a person’s early twenties, presenting the opportunity for possible preventative treatment. Treatments themselves can now be specialized depending on which of the eight disorders a patient suffers from the most.
To identify the gene groups, the study took DNA samples from 4,200 schizophrenia patients and from 3,800 individuals with no symptoms of the disease. Then, it compared the DNA mutations between those with the disease and those without across 700,000 genes to identify those connected to schizophrenia.
Schizophrenia affects about one percent of the population. It’s commonly confused with multiple personality disorder even though the latter is not a symptom of schizophrenia. When untreated, the disease often leads to severe depression, anxiety disorders, and substance use disorders.