(a) (1) Notwithstanding the requirements of subsection (b) of this section, any health benefits plan described in this article that is delivered, issued or renewed in this state shall provide benefits to all individual subscribers and members and to all group members for expenses arising from treatment of serious mental illness. The expenses do not include custodial care, residential care or schooling. For purposes of this section, "serious mental illness" means an illness included in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, as periodically revised, under the diagnostic categories or subclassifications of: (A) Schizophrenia and other psychotic disorders; (B) bipolar disorders; (C) depressive disorders; (D) substance-related disorders with the exception of caffeine-related disorders and nicotine-related disorders; (E) anxiety disorders; and (F) anorexia and bulimia.

(2) Notwithstanding any other provision in this section to the contrary, in the event that an insurer can demonstrate actuarially to the Insurance Commissioner that its total anticipated costs for treatment for mental illness, for any plan will exceed or have exceeded two percent of the total costs for such plan in any experience period, then the insurer may apply whatever cost containment measures may be necessary, including, but not limited to, limitations on inpatient and outpatient benefits, to maintain costs below two percent of the total costs for the plan: Provided, That for any plan year beginning on or after October 3, 2009, an insurer providing a "group health plan," as defined in section one-a of this article, with an average of more than fifty employees on business days during the preceding calendar year, may not apply cost containment measures as provided in this subdivision unless the insurer can demonstrate that the application of this section results in an increase of two percent of the actual total costs of coverage for the plan year involved with respect to medical-surgical benefits and mental health benefits under the plan: Provided, however, That such cost containment measures implemented are applicable only for the plan year following approval of the request to implement cost containment measures.

(3) The insurer shall not discriminate between medical-surgical benefits and mental health benefits in the administration of its plan. With regard to both medical-surgical and mental health benefits, it may make determinations of medical necessity and appropriateness, and it may use recognized health care quality and cost management tools, including, but not limited to, utilization review, use of provider networks, implementation of cost containment measures, preauthorization for certain treatments, setting coverage levels including the number of visits in a given time period, using capitated benefit arrangements, using fee-for-service arrangements, using third-party administrators, and using patient cost sharing in the form of copayments, deductibles and coinsurance.

(4) The amendments to this subsection enacted during the regular session of the Legislature in the year 2009 shall apply with respect to group health plans for plan years beginning on or after October 3, 2009.

(b) With respect to mental health benefits furnished to an enrollee of a health benefit plan offered in connection with a group health plan, for a plan year beginning on or after January 1, 1998, the following requirements shall apply to aggregate lifetime limits and annual limits.

(1) Aggregate lifetime limits:

(A) If the health benefit plan does not include an aggregate lifetime limit on substantially all medical and surgical benefits, as defined under the terms of the plan but not including mental health benefits, the plan may not impose any aggregate lifetime limit on mental health benefits;

(B) If the health benefit plan limits the total amount that may be paid with respect to an individual or other coverage unit for substantially all medical and surgical benefits (in this paragraph, "applicable lifetime limit"), the plan shall either apply the applicable lifetime limit to medical and surgical benefits to which it would otherwise apply and to mental health benefits, as defined under the terms of the plan, and not distinguish in the application of the limit between medical and surgical benefits and mental health benefits, or not include any aggregate lifetime limit on mental health benefits that is less than the applicable lifetime limit;

(C) If a health benefit plan not previously described in this subdivision includes no or different aggregate lifetime limits on different categories of medical and surgical benefits, the commissioner shall propose rules for legislative approval in accordance with the provisions of article three, chapter twenty-nine-a of this code under which paragraph (B) of this subdivision shall apply, substituting an average aggregate lifetime limit for the applicable lifetime limit.

(2) Annual limits:

(A) If a health benefit plan does not include an annual limit on substantially all medical and surgical benefits, as defined under the terms of the plan but not including mental health benefits, the plan may not impose any annual limit on mental health benefits, as defined under the terms of the plan;

(B) If the health benefit plan limits the total amount that may be paid in a twelve-month period with respect to an individual or other coverage unit for substantially all medical and surgical benefits (in this paragraph, "applicable annual limit"), the plan shall either apply the applicable annual limit to medical and surgical benefits to which it would otherwise apply and to mental health benefits, as defined under the terms of the plan, and not distinguish in the application of the limit between medical and surgical benefits and mental health benefits, or not include any annual limit on mental health benefits that is less than the applicable annual limit;

(C) If a health benefit plan not previously described in this subdivision includes no or different annual limits on different categories of medical and surgical benefits, the commissioner shall propose rules for legislative approval in accordance with the provisions of article three, chapter twenty-nine-a of this code under which paragraph (B) of this subdivision shall apply, substituting an average annual limit for the applicable annual limit.

(3) If a group health plan or a health insurer offers a participant or beneficiary two or more benefit package options, this subsection shall apply separately with respect to coverage under each option.