Doctors prescribing a combination of antidepressants and mood stabilizers for bipolar II disorder should consider offering a single-drug treatment instead. Recent findings published in the American Journal of Psychiatry show that combination therapy may actually be the least desirable choice for some patients, reports the Brain & Behavior Research Foundation.

An estimated six million Americans are affected by bipolar disorder, a mental illness that causes unusual shifts in a person’s mood and behavior. This includes manic episodes characterized by extreme elation and energy; depressive episodes characterized by intense sadness; and hypomanic episodes, characterized by a mild mania. Bipolar II disorder, one of the four types of the condition, is associated with the latter two types of moods.

During the 16-week study, researchers at Stanford University observed 142 patients and their response to treatment with three different drugs: the SSRI (serotonin-specific reuptake inhibitor) antidepressant sertraline, the mood stabilizer lithium and a combination of the two meds. To determine how participants reacted to the medications, scientists tracked their mood and the number of mood switches.

Results indicated that 57 percent of participants from all groups showed significant improvement by the study’s end. But findings also showed that those who used both drugs dropped out at a higher rate (70 percent versus 42 percent in the sertraline group and 55 percent in the lithium group) than those who were treated with only one medication.

Although treatment for bipolar II disorder varies, treatment guidelines previously dictated that clinicians use the combination of sertraline and lithium usually prescribed for bipolar I disorder. However, these findings suggest that each drug alone may be a more effective treatment for bipolar II disorder.

Click here to read about the first-ever road map of the bipolar brain.