IStock Photo 1898830 © Kevin Russ

Bipolar disorder is a recurrent instability of mood which, because of its cyclical nature, poses a diagnostic challenge. Researchers in Australia may be on track towards a better tool for identifying people with the illness (popularly known as manic depression). It has long been observed that the condition often runs in families, but until now scientists have been unable to identify a biological marker.

The Australian study involved showing different images the right and left eyes of patients, requiring their brains to rapidly shift from taking in one image to the other. The results showed that the brains of people with bipolar disorder had significantly slower “flip rate” than the control subjects; furthermore, a related study involving identical twins indicated the rate is inherited. The results suggest that a simple eye test might one day be useful as a way to diagnose manic depression.

The odds an adult has classic bipolar disorder are 1 in 35.71 (2.8%), about the same as the predicted odds a woman's first 5 children will be girls (1 in 35.95).

But as definitions of the bipolar spectrum come to include less severe forms of mood instability, the statistic morphs to upwards of 5%, according to Bruce Cohen, president and psychiatrist in chief at McLean Hospital in Belmont, Massachusetts, which conducts intensive bipolar research.

Most bipolar disorders include depression emerging in one’s late teens or early twenties, followed by periods of normalcy and then launching into the cluster of symptoms known as mania—abnormally high energy, rapid speech, reckless pleasure-seeking, delusions of grandiosity, impulsivity, decreased need for sleep, and, at its most severe, hallucinations or other psychoses.

Mania, or its milder precursor, hypomania, is enjoyable to the patient. But the euphoria and heightened productivity initially involved often wind up opening dark worlds of financial debt, family turmoil, job loss, legal trouble, and embarrassment.

McLean Hospital is a sprawling psychiatric hospital campus dotted with neuroscience laboratories affiliated with Harvard Medical School. Cohen has spent the last 30 years there as a clinical psychiatrist and molecular geneticist trying to understand this troubling psychiatric disorder. As he describes it: “We are not that bad at treating mania, we are so-so at stabilizing mood, and we are not so good at treating bipolar depression.” He and his colleagues have found that mood-stabilizing medications can treat mania if a patient follows the regimen. Unfortunately, bipolar depression poses unique treatment challenges.

Bipolar patients tend to spend nearly 3 times as long in depressed mode as in manic. All of the existing antidepressants were developed to treat major depressive disorder, not bipolar depression, and traditional antidepressants can cause people with previously undiagnosed or misdiagnosed bipolar disorder to flip into mania. Because a diagnosis of bipolar disorder can only be confirmed by a manic or hypomanic episode, opportunities to catch burgeoning bipolar depression before a psychiatrist prescribes the wrong antidepressant are missed. Most of the fatalities associated with the disorder occur during depressed phases, with 15%-20% of people with bipolar disorder taking their own lives. And 30% will attempt suicide.

Bipolar disorder requires medication, which may include antipsychotics, benzodiazepines, lithium, and, more commonly, anticonvulsants, which include Lamictal (lamotrigine), Depakote (valproic acid), Tegretol (carbamazepine), and Trileptal (oxcarbazepine). But these medications, many of which cause serious side effects, don’t begin to solve the problem. Success in stabilizing mood depends on long-term adherence to treatment. Bipolar disorder, by nature, involves a lack of insight into one’s behavior. “Someone experiencing mania is not going to voluntarily go to the hospital,” says Cohen. “Most people who have bipolar disorder in the general community are not in any treatment.” The odds an adult who has bipolar disorder will not receive mental health services in a year are 1 in 2.25.

Children who have a parent or sibling with bipolar disorder are 4 to 6 times more likely to develop the illness, compared to children without the family history. Still, most children who belong to a family with such a psychiatric precedent do not inherit the pathological mood swings. Recent genetic research has contributed to a growing consensus that a complex combination of different genes contributes to susceptibility to a bipolar illness.

“Bipolar disorder should be thought of as a family of disorders,” says Cohen, “occurring along a spectrum, which produces varying courses of illness.”

Some people experience episodes of depression and slip into a manic episode once over the course of their lifetimes. Others suffer from what has historically been labeled bipolar II, or depressions interlaced with periods of hypomania. Another 15% of disorders along the bipolar spectrum ricochet from depression to mania multiple times a year, some multiple times a day. Bipolar disorder is usually there for life, though early treatment with mood stabilizers provides the best chances of a milder illness.