Schizophrenia and bipolar disorder both involve genetic mutations that increase the risk of developing the diseases, two new studies report.

The studies also found that the mental disorders share a large amount of genetic overlap.

In one of the studies, conducted at the University of Chicago, researchers reviewed 17 studies encompassing nearly 22,000 people, about half of which were schizophrenia patients. The study uncovered seven genetic variants, five of them new.

One in particular -- known as rs1625579 -- plays a key role in regulating brain cells. The results were published in Nature Genetics.

To scientists then duplicated the genome search with almost 30,000 other patients.

In the other study about patients with bipolar disorder, also published in Nature Genetics, researchers at Mount Sinai School of Medicine in New York first looked at the genomes of 7,481 people with the disorder and 9,250 healthy individuals. The study confirmed a strong link with the CACNA1C gene, which has also has been associated with schizophrenia.

Schizophrenia is characterized by hearing voices that are not real, as well as paranoid thinking and disorganized speech and thoughts. It affects about one percent of adults.

Bipolar disorder is characterized by drastic mood changes that swing from severe depression to euphoria, and it also affects about one percent of the population.

Researchers of both studies are hopeful that learning more about the affected pathways in the brain will lead to a better understanding of what causes schizophrenia and bipolar disorder, and that better drug treatments can be developed as a result.

Bipolar disorder and schizophrenia share striking brain similarities, according to new research by the Royal College of Surgeons in Ireland and Beaumont Hospital.

The new study also found that in both conditions, a process occurs affecting how information is transmitted from neuron to neuron, a finding which could lead to the developments of improved treatments.

This was the first study to look at sub-regions of the hippocampus, the region in which abnormalities most often occur in both schizophrenia and bipolar disorder. Certain areas of the hippocampus were discovered to be different in people with the disorders, in terms of how proteins are affected, compared to the normal population.

Additionally, in both conditions, a process occurs which controls how information is transmitted by the shuttling of proteins to and from the synapse.

"Our study is the first to show the depth of protein similarities between schizophrenia and bipolar disorder as they appear in the brain and the processes associated with them,” said Professor David Cotter of the Department of Psychiatry, RCSI and Beaumont Hospital, as quoted by News Medical. “Although, the two conditions present with different symptoms, the research has shown that they are almost identical in terms of how they present in the brain.” 

Stem cell research conducted at the University of Michigan is showing new promise in unlocking the biological secrets that make up bipolar disorder.

By taking stem cell lines from the skin of bipolar adults, scientists will be able to uncover new findings from the cell donors, who are participating in the study.

According to Melvin McInnis, Professor of Bipolar Disorder and Depression at the U-M Medical School and associate director the U-M Depression Center, the new research could lead to treatments that are more effective.

“Currently the best treatments for bipolar disorder are only effective for 30 percent to 50 percent of patients. New discoveries have been limited, in part due to the lack of access to tissue and cells from individuals with bipolar disorder. But that is now changing because of the Prechter research program and advances in stem cell research,” McInnis said, as quoted by www.uofmhealth.org.

The new stem cell lines were created out of fibroblasts taken from skin samples from both adults with bipolar disorder and without the disorder. In the lab, scientists manipulate these cells to develop into different types of body cells.

Sue O’Shea, Ph.D., a professor of cell and developmental biology at the Medical School, says the goal is to develop 30 cell lines. So far, five have been created.

The bipolar treatment drug Abilify is used frequently in the long-term care of patients, but its use is based largely on a single questionable clinical trial and could potentially be keeping doctors from prescribing more established drugs, a new review suggests.

Abilify (aripiprazole), originally used to treat patients with schizophrenia and acute episodes of mania, was approved by the FDA to treat bipolar patients in 2005. Since then it has become one of the most popular treatments for bipolar maintenance therapy.

However, according to Alexander C. Tsai of Harvard University, a lead author on the study, there is not enough research to support the drug’s widespread use.

"We failed to find sufficient data to support its use,” Tsai said, as quoted by CNN Health. "It may actually be working for some people, but it's certainly worth talking to your doctor about how it's working for you."

Tsai and colleagues only found one randomized-controlled clinical trial which studied the use of Abilify, and it had several limitations: it was short (only 26 weeks) and only one-fifth of the patients completed the 48-hour follow-up phase. The study population was also limited to bipolar patients whose moods had already stabilized.

"Frankly, I think it's an embarrassment to the profession that [Abilify] has been accepted so uncritically for this indication,” CNN Health quoted Tsai as saying.

According to Gregory E. Simon, M.D., a psychiatrist at Group Health Research Institute in Seattle, lithium is a much more well-supported treatment for bipolar disorder. 

Catherine Zeta-Jones spoke out about her battle with bipolar disorder, saying "there is no need to suffer silently."

The 41-year-old Hollywood star said last month she was treated for five days at a hospital after becoming stressed due to her husband Michael Douglas’ battle with throat cancer.

In a statement released to this week's People magazine, she said: "This is a disorder that affects millions of people and I am one of them. If my revelation of having Bipolar II has encouraged one person to seek help, then it is worth it. There is no need to suffer silently and there is no shame in seeking help."

Bipolar disorder is a mental illness where sufferers have elevated or irritable moods alternating with periods of depression. Bipolar II is has longer mood swings and more severe depression, usually triggered by major life changes.