The medical director of a troubled state-run psychiatric hospital in Fairfax County abruptly resigned Wednesday -- less than six months after taking the job -- continuing an exodus of clinical staff from the facility.

John N. Follansbee had been recruited from England to help revamp the beleaguered Northern Virginia Mental Health Institute after the death of a 26-year-old patient last summer.

Follansbee gave no reason for his resignation. Surprised colleagues said he had told them he wanted to continue working at the hospital.

But authorities familiar with the hospital said Follansbee had disobeyed his superiors and had been in contact this year with an investigator from the U.S. Justice Department regarding conditions at the hospital. The facility has been under federal scrutiny for five years, and in 1996 the Justice Department filed a lawsuit to improve conditions there.

A spokesman for Virginia Attorney General Mark L. Earley (R) declined to comment, but a state official familiar with the case said that the office had advised Follansbee to avoid talking to a federal investigator. The source also said that the incident did not have any bearing on Follansbee's resignation.

A spokeswoman for the Department of Mental Health, Mental Retardation and Substance Abuse Services also declined to comment, citing a policy not to discuss personnel matters.

Follansbee's departure is the latest in a string of resignations that have plagued the facility in the past year. The 148-bed facility treats Virginians with serious psychiatric disabilities.

The hospital's previous medical director, Roger Peel, resigned abruptly in September shortly after the death of Skander Najar, whose bleeding pancreas was diagnosed too late to save his life. Another mental patient died a month later just after being admitted to the hospital.

An internal investigation conducted by the institute blamed the medical staff for Najar's death, saying he was provided inadequate care, partly because of poor communication between nurses and doctors.

Shortly after Peel's departure, eight of the 10 psychiatrists and three psychologists resigned. Then this year, two of the psychiatrists hired as replacements also left before their 90-day probation period was complete. Last month, three more psychologists resigned.

Richard A. Kellogg, commissioner of the state agency that oversees the facility, said staff turnover is a concern but is also the inevitable result of change at the institute.

"We are all concerned about the turnover, but we do need to get the right staff and the right professional credentials to work in the treatment team model if we are going to have success in the future," Kellogg said.

Since 1990, federal officials have been scrutinizing the state mental hospital system, which cares for 3,800 patients in 15 facilities. The Northern Virginia facility was one of three that the federal government sued to improve care.

The Justice Department began investigating the Northern Virginia hospital in 1994, after the death of three patients within a year, and brought court action in 1996. Under a settlement reached in 1997, the facility agreed to make improvements, including increased medical supervision of patients.

In January, the state agency tapped Follansbee, a consultant psychiatrist with the private St. Andrews Hospital in Northampton, England, to rebuild the staff that had been decimated by the resignations.