 Using eleven years 2004-2014 of claims data from the largest US commercial health insurer, the investigators will assess the impact of switching into high-deductible health plans HDHPs on outcomes for patients with bipolar disorder. Patient subgroups will include patients with and without high medication cost-sharing and vulnerable populations racialethnic minorities, poor, rural, major comorbidities. Interviews with patients and caregivers recruited through a major advocacy group will provide further insights into the policy issues with real-life experiences. 