VACAVILLE, May 11 – Charles Manson was transferred to the California Medical Facility today for a 90-day psychiatric study because he was “becoming extremely withdrawn,” a prison official said.

Manson, 41, is serving a life sentence after being convicted of masterminding the 1969 murders of actress Sharon Tate and six other persons.

A spokesman for the Vacaville medical prison, Thomas Charleston, said Manson had regularly refused to leave his cell at Folsom Prison.

At Vacaville, he will be kept in a cell by himself and will see only guards and psychiatric workers, prison officials said.

Manson spent seven months at Vacaville in 1974 but was transferred to Folsom after prison officials said they intercepted letters to two of his disciples, Lynette Fromme and Sandra Good, that talked about a future escape attempt.

Miss Fromme was convicted last year of attempting to assassinate President Ford, and Miss Good was found guilty recently of threatening the lives of business and government leaders.