Trends in Prescriptions of Lithium and Other Medications for Patients with Bipolar Disorder in Office-based Practices in the United States: 1996-2015

Background Studies have shown that rates of lithium use for bipolar disorder (BPD) in the United States declined through the 1990s as other mood stabilizing anticonvulsants and second-generation antipsychotics (SGAs) became more popular. We examined recent prescribing trends of medications for BPD over the past two decades. Methods Twenty years of data (1996-2015) from the National Ambulatory Medical Care Survey (NAMCS) were used. Weighted percentages of prescriptions of lithium, anticonvulsants, SGAs and antidepressants were calculated over two-year intervals. Logistic regression was used to examine factors related to polytherapy. Results Prescriptions of lithium declined from 38.1% (95%CI: 29.8% - 46.3%) in 1996-97 to 14.3% (95%CI: 10.6% - 18.1%) in 2006-07 and has remained stable since. During this time, prescriptions of SGAs more than doubled. SGAs and/or anticonvulsants were prescribed in 78.6% (95%CI: 73.0% - 84.2%) of BPD visits in 2014-2015. Polytherapy increased by approximately 4% every two years and in 2014-15 occurred in over 35% of BPD visits. Antidepressants were prescribed in 40-50% of BPD visits, but their prescriptions without other mood stabilizers decreased from 18.2% (95%CI: 11.7% - 24.8%) in 1998-99 to 5.8% (95%CI: 3.0% - 8.6%) in 2014-15. Limitations The sample had limited power to study the effect of individual medications or the potential for differing effects in certain subgroups of patients. Conclusions This study further documents the declining prescriptions of lithium for BPD, and corresponding increase in prescriptions of anticonvulsants and SGAs, despite the fact that lithium is typically recommended as a first line therapy for BPD.