Head of O.C.-Based Psychiatric Centers Quits : Health care: The embattled hospital operator also said it will eliminate five regional divisions and several dozen jobs.

Community Psychiatric Centers, reeling from a yearlong series of shocks that included a 48% plunge in annual earnings and a suspension of dividend payments to shareholders, said Wednesday that its president has left and that it will eliminate five regional divisions.

The reorganization of the hospital operator, announced after the stock markets closed Wednesday, left Community Psychiatric without Loren B. Shook, a 10-year veteran of the company who took over the top operational post a year ago.

Although the company said Shook left voluntarily, his departure came in the wake of continuing financial turmoil. In addition, several dozen jobs, including those of six former regional vice presidents, have been eliminated. A company statement indicates that further hospital closures could follow.

The management reorganization, part of an overall restructuring of the Laguna Hills-based company, will help improve its performance, Richard L. Conte, chairman and chief executive, said in a statement.

Conte also promised “to continue to streamline our cost structure,” including, apparently, dumping some hospitals. The goal, he said, is “the delivery of a lower-cost service and a smaller base of hospital operations.”

Since May, the company has closed six hospitals in the United States, including four in California. It now operates 45 psychiatric hospitals and two long-term acute care facilities in the United States and England.

Suzanne Hoveday, a company spokeswoman, said that not all of the people affected by Wednesday’s shuffle will be laid off: Some will be offered transfers to jobs in other areas of the company. She was unable to provide any specifics.

Once a darling of the health care industry, with meteoric rises in its earnings and stock values, Community Psychiatric has suffered with the rest of the medical industry from the recession and the national drive to slap a cap on soaring health care costs.

The company’s stock closed at $11 a share on the New York Stock Exchange Wednesday, down 25 cents for the day and far below its historic high of $40, reached in 1991.

In addition to its financial woes--the company lost nearly $33 million in the first half of fiscal 1993 and is readying a third-quarter earnings report that analysts don’t expect to brighten the gloomy picture. Community Psychiatric has been plagued over the last 18 months by news of an insurance fraud probe in Texas and suits by several former employees who say they were fired for reporting that some workers’ credentials were faked by their superiors.

Community Psychiatric was not fined in the Texas case, while three other hospital companies were--a sign, the company maintains, that it was cleared of any wrongdoing. The employees’ wrongful-firing suits and the allegations they contain are still weaving their way through the civil courts, but company officials deny the allegation that signatures verifying credentials for some employees were forged.

Shook’s departure was not linked in any way to the lawsuits or the Texas probe, Hoveday said.

Shook, 42, oversaw all of the company’s hospital operations outside of California--a job that will be taken over by Kay E. Seim, 46, executive vice president who previously headed one of the company’s California divisions.

Reporting to Seim will be senior vice presidents heading Community Psychiatric’s four expanded regions, which replace the nine regional operations that existed before Wednesday’s reorganization.

The shake-up does not affect the company’s seven-hospital United Kingdom division or its Transitional Hospitals Corp. subsidiary, which operates two acute-care facilities and shares operation of a third with the company’s psychiatric division.