Welf. & Inst. Code, § 4125

(a) The director may deposit any funds of any patient in the possession of each hospital administrator of a state hospital in trust with the treasurer pursuant to Section 16305.3 of the Government Code or, subject to the approval of the Department of Finance, may deposit these funds in an interest-bearing bank account or invest and reinvest these funds in any security described in Article 1 (commencing with Section 16430) of Chapter 3 of Part 2 of Division 4 of Title 2 of the Government Code, and for the purposes of deposit or investment only may mingle the funds of any patient with the funds of any other patient. The hospital administrator with the consent of the patient may deposit the interest or increment on the funds of a patient in the state hospital in a special fund for each state hospital, to be designated the “Benefit Fund,” of which the hospital administrator shall be the trustee. He or she may, with the approval of the director, after taking into consideration the recommendations of representatives of patient government and recommendations submitted by patient groups, expend the moneys in this fund for the education or entertainment of the patients of the institution.

(b) On and after December 1, 1970:

(1) The funds of a patient in a state hospital or a patient on leave of absence from a state hospital shall not be deposited in interest-bearing bank accounts or invested and reinvested pursuant to this section except when authorized by the patient.

(2) Any interest or increment accruing on the funds of a patient on leave of absence from a state hospital shall be deposited in his or her account.

(3) Any interest or increment accruing on the funds of a patient in a state hospital shall be deposited in his or her account, unless the patient authorizes their deposit in the state hospital’s benefit fund.

(c) Any state hospital charges for patient care against the funds of a patient in the possession of a hospital administrator or deposited pursuant to this section and used to pay for that care, shall be stated in an itemized bill to the patient.

(d) No later than August 15 of each year, the director shall provide to the Legislature a summary data sheet containing information on how the benefit fund at each state hospital was expended in the previous fiscal year.