<qa>  What is the name of the cohort that will include traditional plan members with bipolar illness?Investigators will include health plan members aged 12 to 63 years at the beginning of the baseline period. Consistent with prior research,89-91 we will use medical claims data and a validated algorithm to identify members who had at least two ambulatory encounters or one hospital encounter with a diagnosis of bipolar disorder. Intervention cohorts will include traditional plan members with bipolar illness who experience an employer-mandated switch to HSA-eligible HDHPs with full drug cost-sharing or to HSA-ineligible HDHPs that subject medications only to copayments as in traditional health plans. 