Patients with type I BD were participants in one of two prospective clinical trials of Li monotherapy for identifying genetic variants predictive of good Li response. These studies included one of Li response in veterans conducted at the University of California, San Diego; the other was the Pharmacogenomics of Bipolar Disorder Study (clinical trial number NCT01272531; Supplementary Table 5). All subjects provided written informed consent and all procedures were approved by local human subjects committees. Subjects were initially screened for eligibility and diagnoses determined using the Diagnostic Interview for Genetic Studies. Subjects were started on Li. Over 4 months they were titrated up to a therapeutic level (1.0 meq dl−1) as tolerated, as other psychotropic medications were gradually discontinued. Subjects were seen at 2- to 4-week intervals and rated for mood symptoms. After 4 months, subjects with a Clinical Global Impressions Scale score of 3 or less, reflecting only mild symptoms, were declared responders, whereas other subjects were deemed non-responders. Li responders were then followed on Li monotherapy for up to 2 years. The responders remained stable for an average
