Eli Lilly and Co. is losing its head of neuroscience research, the company confirmed.

David Bredt, vice president of neuroscience research, has resigned effective Friday “to pursue other opportunities,” according to Lilly spokeswoman Judy Kay Moore. Bredt had overseen Lilly’s development of various drugs, including molecules in late-stage human testing to treat Alzheimer’s disease and depression.

In addition to those Phase 3 drug candidates, Lilly has three neuroscience drugs in Phase 2 clinical testing. They include a schizophrenia drug like Lilly’s blockbuster Zyprexa that does not appear to cause the side effects that Zyprexa does, as well as a drug to treat alcohol dependency and another to treat agitation in Alzheimer’s patients.

But Bredt also oversaw the major failure of a second experimental Alzheimer’s drug. Lilly halted a Phase clinical trial of semagacestat in August after it worsened the condition of patients.

“We at Lilly thank Dr. Bredt for his many significant contributions to our neuroscience portfolio over the past several years and, before that, as vice president of integrative biology. We wish him well in his future endeavors,” wrote Moore in an e-mail.

She added, “Lilly has a strong history in neuroscience research and development, and neuroscience remains a major therapeutic focus of ours.” She said Lilly would begin a search for a successor.

Bredt came to Lilly in 2004 after many years at the the University of California at San Francisco Medical School. He did his graduate work at Johns Hopkins University in Baltimore, conducting research that greatly advanced insights on nitric oxide as a neurotransmitter in the brain, according to a 2005 article in a Johns Hopkins newsletter.