"We recognize the public interest in supporting effective treatment of mental illness and in protecting the rights of patients to privacy . . ., and the consequent public importance of safeguarding the confidential character of psycho-therapeutic communication. Against this interest, however, we must weigh the public interest in safety from violent assault."

"`There is no privilege . . . if the psychotherapist has reasonable cause to believe that the patient is in such mental or emotional condition as to be dangerous to himself or to the person or property of another and that disclosure of the communication is necessary to prevent the threatened danger.'"

"We conclude that the public policy favoring protection of the confidential character of patient-psychotherapist communications must yield to the extent to which disclosure is essential to avert danger to others. The protective privilege ends where the public peril begins."