One in every 100 people will experience bipolar disorder at some time during their lives. It is a mental illness that causes extreme moods that swing from emotional highs (mania or hypomania) and crushing lows (depression). It's safe to say most people have a general idea what bipolar disorder is-movies and TV shows like Silver Linings Playbook, Homeland and Shameless all feature bipolar characters, and many celebs have been open about their diagnosis, such as Miley Cyrus, Catherine Zeta-Jones, and, more recently, Mariah Carey.

But still, bipolar disorder is often misunderstood-and sometimes, people go years before they are properly diagnosed. In her People magazine interview, Carey revealed she originally thought her bipolar disorder was a sleeping problem. "But it wasn’t normal insomnia, and I wasn’t lying awake counting sheep," she said. "I was working and working and working…I was irritable and in constant fear of letting people down.” It turned out that she was actually experiencing a manic episode.

“The most important thing to realise is that bipolar is a real brain disorder,” says psychiatrist Dr Colleen McClung. “It’s not something where people just have mood swings that they can control. It should be treated the same-in terms of the way people think about it-as heart disease or cancer.”

Types of bipolar disorder

Also known as manic-depressive illness, bipolar disorder falls into three main categories:

  • Bipolar I is diagnosed when someone has a manic episode, which lasts at least a week. The manic periods are followed (or preceded) by depressive or hypomanic episodes.
  • Bipolar II is diagnosed when someone experiences at least one hypomanic episode and one depressive episode (but they’ve never had a manic episode).
  • Cyclothymic disorder is a milder form of bipolar where people regularly experience mood swings with depressive and hypomanic symptoms over at least a two-year period.

What are mania and hypomania, exactly?

Depressive episodes, on the other hand, manifest many of the same symptoms we relate to major, or unipolar, depression. In this state, people will feel extremely down, hopeless, unenergetic, forgetful, disinterested and unable to concentrate. They take no pleasure in things they used to. They’re also more likely to contemplate death and suicide.

The frequency and duration of these episodes varies quite drastically from person to person, said McClung. “There are people who seem to be cycling several times in the period of a month or two, whereas other people can literally go months between episodes,” she explains.

How to spot bipolar disorder

It's important for bipolar patients to be tuned into their own relapse symptoms, and to share a collaborative care plan with close, trustworthy friends and family members. That way, supportive loved ones can identify signs of an impending episode and help them get treatment-usually medication or therapy-before the mood swing becomes more severe.

And the symptoms can be more subtle than you might guess. “Changes in sleep, energy, cognition, appetite, tolerance for frustration-those are all part of the plans people put together where they lay out how they know they’re well, how they know they’re headed toward a depression, and how they might know that they’re headed toward hypomania or mania,” says Dr. Sachs.

Having that support system makes all the difference, he added. “There’s an expectation that you ought to man up and manage this on your own, that you should be in control of it. Once people get past that misconception and include external supports, they tend to do much better than when they try to do it on their own. The difference in prognosis is night and day.”