A promising schizophrenia drug showed mixed results. What does that mean for patients?

Some people who took a new schizophrenia drug for a year improved with only a few side effects, but many dropped out of the research, the company announced Thursday.

The results underscore the difficulties in treating schizophrenia, a severe mental illness that can cause people to hear voices, feel paranoid and withdraw from others. High dropout rates are typical in schizophrenia drug studies.

Finding a drug that works can be a long ordeal punctuated by crises and hospitalizations. Side effects of existing medications — weight gain, tremors, restlessness — cause some people to stop taking medicine and relapse.

There's been great hope among doctors for Cobenfy, which was approved in September, because it acts in the brain differently than other schizophrenia drugs. Instead of blocking dopamine receptors, Cobenfy’s main ingredient, xanomeline, works on a different receptor that indirectly blocks dopamine release.