One of the characteristics of bipolar disorder is the extreme periods of positive mood, or mania. People in the grip of mania also have increased energy, sleep less, and experience extreme self-confidence. At first glance, this may sound good and even desirable. However, during these times of mania, people with bipolar disorder often take dangerous risks, run up their credit card debt, and wreak havoc in marriages. "The fact that positive emotion has gone awry is something unique about bipolar disorder, as almost all other emotional disorders are characterized by difficulties in negative emotions" Gruber says.

Gruber points out that positive emotions are problematic for people with bipolar disorder even when they're not experiencing mania. Gruber has studied people whose bipolar disorder is in remission and found that they still experience more positive emotions than people who have never had bipolar disorder. More positive emotions may not sound like a bad thing, but there are times when these positive emotions aren't appropriate. "In our work, those with bipolar disorder continue to report greater positive emotions whether it's a positive film, very sad film clip of a child crying over his father's death, and even disgusting films involving someone digging through feces" she says. In more recent work Gruber and her colleagues have found they still feel good even if a close romantic partner tells them something sad face to face, they still feel good. "It's rose-colored glasses gone too far."

Clinical psychologists may also be able to use this research to figure out who with bipolar disorder is likely to relapse; people who have a lot of positive emotions, even at inappropriate times, may provide a window into possible early warning signs, Gruber says. In a study of healthy college students who had never been diagnosed with bipolar disorder, Gruber found that those who showed these same high levels of positive emotions that persisted across positive, negative and neutral situations were at higher risk for bipolar disorder.

But not all emotions are alike in bipolar disorder; in fact, they seem to have particular kinds of positive emotions. They report feeling more achievement and self-focused emotions like pride and rewarding feelings like joy. They don't differ social emotions that connect us with others, like love and compassion. "This mirrors early clinical observations and more recent scientific work," Gruber says -- that people with bipolar disorder set very high, ambitious goals, are sensitive to rewards, and in periods of mania, some believe they have special powers.

Psychologists should also consider that there are downsides of positive emotions even for people who don't have bipolar disorder, Gruber says. "Although positive emotions are generally good for us, when they take extreme forms or when they're experienced in the wrong context, the benefits of positive emotion begin to unravel," she says. The goal: "experience it in moderation, in the right place and time."