Lithium vs Valproate Addressing Impulsivity Related to Mood Disorders
Bipolar disorder bears with it a significant risk of suicide, as between 4 and 19% of those with this diagnosis will successfully kill themselves. A colleague, Todd Gould at University of Maryland, has a hypothesis that suicide is so common in bipolar because the disease causes individuals to make impulsive choices that fail to take into account future consequences, and that medications could ameliorate this risk. To study this, we utilized mice selectively bred at IUPUI to drink ethanol excessively, called High Alcohol Preferring mice. Even when sober, these mice show highly impulsive choices, preferring immediate rewards at the cost of rewards given later. We administered two drugs commonly used to treat bipolar disorder: valproate and lithium. We showed that lithium was more effective than valproate at treating this excessive impulsivity. Recent work validates our approach using animals, as a meta-analysis published five years after our work appeared showed that lithium was more effective than valproate at reducing suicidality in bipolar patients.