Doctors say there aren't enough good options for treating patients with schizophrenia and bipolar disorder, but a new collaboration between scientists at several institutions and a pair of drug companies could lead to additional, and more effective, medications in coming years.

Researchers from the Johns Hopkins University School of Medicine and the Salk Institute for Biological Studies in San Diego will lead the effort to build a stem cell-based method of assessing drugs for the widespread mental health disorders.

The project will be funded by a $15.4 million grant from a program at the National Institute of Mental Health created in 2013 to promote such collaborations.

The type of stem cells that will be used in the research, called induced pluripotent stem cells, are typically taken from people's skin or blood and made to behave like brand-new human cells that can grow into any type of cell.

In this case, the cells will be taken from 50 volunteers with the disorders and turned into nerve cells that can be tested in the lab to show scientists how different drugs affect them. The researchers say the process will be standardized so others can grow stem cells and test drugs in the same way.

“There has been a bottleneck in stem cell research,” Hongjun Song, a Hopkins professor of neurology and neuroscience, said in a statement. “Every lab uses different protocols and cells from different patients, so it's really hard to compare results. This collaboration gathers the resources needed to create robust, reproducible tests that can be used to develop new drugs for mental health disorders.”

Millions of Americans suffer from schizophrenia or bipolar disorder.

Usually diagnosed in young adults, schizophrenia affects how a person thinks, feels and behaves. Those who suffer from it have trouble thinking rationally and managing social behavior. It is a chronic and severe disorder and can be very disabling, according to the National Institutes of Mental Health. It affects about 3 million Americans, and current treatments only target symptoms.

Bipolar disorder, also called manic-depressive disorder, affects more than 5 million Americans. Existing treatments only help the depressive or manic swings, but not both.

Dr. Scott Aaronson, a psychiatrist and director of clinical research for the Sheppard Pratt Health System, the state's largest provider of mental health services, said that while new treatments are not on the immediate horizon, the effort creates a means to identify possible medications that doesn't now exist.

Aaronson, who is not involved in the new collaboration, said most drugs for schizophrenia and bipolar disorder were not found on purpose or because scientists understood the underlying pathology of the illnesses. This approach will allow the scientists to see the drugs in action on human cells, creating a better opportunity to find more effective medications.

And because they are standardizing the way the stem cells are made and used, other researchers will be able to build on the work.

“Now we have between a third and a half of people sub-optimally treated because the medications may only treat a part of the patient population,” Aaronson said. “The other problem is we think of bipolar disorder as a disorder, but it's really disorders, plural.

“There can be many dysfunctioning genes, meaning the illness is different in different people and the drugs may not work.”

Aaronson said he's working on different combinations of existing drugs to treat patients. New drugs, he said, are critical.

In addition to Hopkins and Salk, the collaboration includes the University of Michigan; Sanford Burnham Prebys Medical Discovery Institute, a nonprofit research outfit; Janssen Research & Development, a research arm of a Johnson & Johnson pharmaceutical company; and Cellular Dynamics International, a manufacturer of stem cells.

meredith.cohn@baltsun.com