LINCOLN, Neb. (AP) — The CEO of a state-run psychiatric hospital resigned last week, effective immediately.

Bill Gibson stepped down as head administrator of the Lincoln Regional Center in Lincoln, as well as other regional facilities in Norfolk and Hastings.

Gibson has led the center since 2001. Nebraska Department of Health and Human Services spokesman Russ Reno did not say why he resigned.

Sheri Dawson, acting director of the department’s behavioral health division, will serve as the center’s interim CEO.

The resignation comes at a time of transition under new Gov. Pete Ricketts. Leadership has changed at all but two department divisions since Ricketts took office in January. He also hired a new CEO for the department, Courtney Phillips, who started in April.