Lithium and Quetiapine Have Similar Efficacy in Bipolar Disorder
In a recent study comparing the efficacy of lithium and the second-generation antipsychotic quetiapine, the drugs had remarkably similar results. Researcher Andrew Nierenberg et al. presented the results at the 2014 meeting of the American Society of Clinical Psychopharmacology. In the 6-month study called CHOICE (Clinical Health Outcome Initiative Comparative Effectiveness), 482 patients received either lithium or quetiapine in addition to other medications in a manner consistent with clinical practice. For the purposes of the study, those receiving lithium could not receive quetiapine or another antipsychotic, and those receiving quetiapine could not receive lithium or another antipsychotic, but both groups could receive other types of adjunctive medications.
By the end of the 6-month study period, most patients had improved substantially, but only about a quarter of each group became truly well. The researchers suggest that patients may need a longer period of treatment or other interventions such as psychotherapy or combination treatment. Clinicians were told to use the maximum dose of lithium or quetiapine that each patient could tolerate. Mean maximum doses were 1007.5mg of lithium and 344.9mg of quetiapine.
One surprise for the researchers was that 24% of lithium patients and 27% of quetiapine patients required no other medications and improved on monotherapy.
While results were very similar for two drugs, lithium produced slightly greater side effects and produced slightly better results in patients with anxiety. This may have been due to those patients also receiving benzodiazepines, and the researchers are analyzing data to see whether the patients with anxiety did indeed receive this kind of adjunctive treatment. Quetiapine was slightly better in patients who had more manic symptoms.
In another surprise finding, patients with bipolar II disorder fared better overall than patients with bipolar I disorder. Patients with higher suicide risk did worse than those with lower suicide risk.
