People with bipolar disorder tend to have extremely sensitive circadian systems, which makes it much more difficult for them to recover from disruptions in sleep and routine. In contrast, people without bipolar disorder generally recover fairly quickly if their systems are thrown off by a change in routine or loss of sleep and might even be temporarily energized by these alterations.

Frank studied 175 adult patients with bipolar disorder and compared the effects of two approaches when combined with a common medical treatment for bipolar disorder, usually lithium carbonate: the first was interpersonal and social rhythm therapy, in which patients use a self-monitoring instrument to record and monitor the regularity of their daily routines—for example, their sleep patterns, meal times and physical activity. The second approach involved an intensive clinical management paradigm focusing just on patients’ mood symptoms and management of medication side effects.

The study found that patients who participated in interpersonal and social rhythm therapy in the earlier phases of the trial were able to go longer without a new episode of mania or depression than those who received clinical management.

Frank notes that many study participants had other medical and psychiatric conditions that also had important effects on their treatment outcomes. She adds that her study was conducted in an academic environment using highly trained therapists, so results from other settings might be different.

In a related study presented at the meeting, researchers studying circadian rhythms in mice found that the genes that regulate these rhythms also control the activity of neurons in the brain that utilize dopamine, a neurotransmitter implicated in motivation and emotion. Mice that are lacking some of the key circadian genes closely resemble bipolar patients in the manic state.

Lead researcher Colleen McClung, Ph.D., assistant professor of psychiatry at the University of Texas Southwest Medical Center, says these mice are the most well characterized animal models of human mania that have been described. Symptoms of mania include increased energy, activity, and restlessness; excessively good, euphoric mood; and poor judgment.

While there has long been an association between circadian rhythms and bipolar disorder, no studies have examined whether these rhythmic disruptions contribute to the symptoms associated with bipolar disorder. McClung says the findings of this study bring researchers one small step closer to discovering why bipolar disorder occurs at all, even though the study was done in mice, not humans, and that many more studies will be needed to discover a cure.

ACNP, founded in 1961, is a professional organization of more than 700 leading scientists, including four Nobel Laureates. The mission of ACNP is to further research and education in neuropsychopharmacology and related fields in the following ways: promoting the interaction of a broad range of scientific disciplines of brain and behavior in order to advance the understanding of prevention and treatment of disease of the nervous system including psychiatric, neurological, behavioral and addictive disorders; encouraging scientists to enter research careers in fields related to these disorders and their treatment; and ensuring the dissemination of relevant scientific advances.