Gene Variants Prove Complexity of Schizophrenia and Bipolar Disorders

A total of 30,000 common gene variations have now been linked to the mental illness known as Schizophrenia. In addition, a similar pattern was discovered in people with bipolar disorder, commonly known as manic depression, indicating a overlap between the two conditions that was previously unrecognized.

Three studies conducted by a team of multinational researchers, the International Schizophrenia Consortium, the Molecular Genetics of Schizophrenia consortium and SGENE, examined the DNA of almost 10,000 people who suffer from schizophrenia and that of about 20,000 people without the disorder. The combined results of the studies determined that 30,000 gene variations exist that may contribute to the mental illness. Another significant discovery of the analyses was that schizophrenia and bipolar disorder share similar genetic patterns that challenge the current course of psychiatric treatment and research in regarding the two disorders as being unrelated. The studies appear in the journal Nature.

The researchers acknowledge that the findings prove that these mental illnesses are far more complex than had been previously understood. They also noted that the data clearly indicate that the possibility of developing of any type of rapid test for predicting either disease remains in the distant future.

The London Institute of Psychiatry’s Mick O’Donovan, a member of the research team, said, “It's like we've got a ‘join-the-dots picture,’ and we now know we have several thousands of dots to be joined. But, we don't even have numbers on them yet, so we don't know in what order to connect them up.” O’Donovan also noted that it would be “entirely unscrupulous” for the results of the analyses to be used to offer any kind of genetic test.

The researchers pointed out that although the scope of the studies was vast and did produce an enormous amount of crucial data that will assist in the genetic research of mental diseases, the goal of being able to predict an individual’s specific risk of developing the diseases is still a long way off. According to Pablo Gejman of North Shore University Health System Research Institute in Evanston, Illinois, who worked among the researchers, “We are far away from being able to tell a family: ‘Your child will develop schizophrenia' or not.’”

Kari Stefansson, chief executive of Decode Genetics of Iceland, and co-author of one of the studies explained, “Discoveries such as these are crucial for teasing out the biology of the disease making it possible for us to begin to develop drugs targeting the underlying causes and not just the symptoms of the disease.”

Although the cause of schizophrenia remains unclear, it is believed that as many as 90 percent of cases may be inherited. Schizophrenia is a chronic and often devastating form of mental illness that affects about approximately 1 percent of adults worldwide. Symptoms commonly appear in late adolescence or early adulthood, and can include delusions, hallucinations, paranoia, and depression. Although some antipsychotic drugs, such as AstraZeneca's Seroquel and Eli Lilly's Zyprexa, can alleviate symptoms, there is no known cure for the disease, and the drugs can have serious side effects.

Bipolar disorder also affects about 1 percent of the population. It is an illness that causes extreme mood changes from manic episodes of very high energy to the extreme lows of depression. A variety of medicines are used to treat the disorder, ranging from mood stabilizers to antipsychotics to antidepressants. Bipolar disorder often develops in a person's late teens or early adult years. It is believed that the disorder is caused by a combination of genetic and environmental factors. Just as with Schizophrenia, there is no known cure for the disease.