Cal. EDC § 24011

A member who qualifies for disability allowance pursuant to this chapter because of a disabling impairment that is amenable to treatment that could be expected to restore the member’s ability to perform service in the member’s former position of employment or a comparable level position shall participate in a treatment program prescribed by the member’s primary treating physician. Willful failure to initiate and continue participation in the treatment program shall cause the disability allowance to be terminated. In determining whether a member has good cause for failure to follow the treatment program, the board shall take into account whether treatment would abridge the member’s right to the free exercise of religion or whether the member’s physical or mental condition has worsened, as determined by the member’s treating physician and substantiated by medical evidence.