US rapper and apparent presidential candidate Kanye West has opened up in the past about his struggles with bipolar disorder.
But his recent erratic behaviour has again called into question his health and treatment.
He launched his election campaign Sunday with a rambling speech that saw him rant incoherently, reveal he had wanted to abort his daughter, and break down in tears.
Other celebrities who have spoken publicly about their diagnoses include actor Stephen Fry and the late fashion designer Alexander McQueen.
Bipolar disorder, formerly known as "manic depression," is characterized by extreme mood swings.
On the one hand, patients experience very high periods known as "mania" when they feel energized, elated and can make reckless decisions. They sometimes also experience delusions.
"They can almost have no inhibitions at all, which means they can spend their life savings in a day," said Andrew Nierenberg, a psychiatry professor at Harvard.
"They can do something that's really bad judgment that they wouldn't ordinarily do, either sexually, or in relationships, or work."
The other "pole" of the illness is depression: ultra-low episodes that can include inability to feel pleasure and suicidal thoughts.
In fact the suicide rate among bipolar disorder patients is 10–30 times higher than that of the general population.
The illness affects up to three percent of the population, which makes it more common than schizophrenia but rarer than depression.
And there can be much variation among patients, said Timothy Sullivan, the chair of psychiatry at Staten Island University Hospital.
Some are more depressive and rarely manic, while others are the other way around.
As a result, diagnoses are typically delayed for years. If a patient has so far only experienced depression, they may be misdiagnosed.
West first revealed his diagnosis on his 2018 album "Ye," where he called it his "superpower." Last year, he revealed it caused him paranoid delusions and described being handcuffed during treatment.
Bipolar disorder is known to be "one of the more heritable mental illnesses" said Katherine Burdick, a psychologist at Harvard and the Brigham and Women's Hospital.
If one of your parents had the disorder, your risk is somewhere between 10 to 20 percent.
Scientists are looking for the genes responsible, and trying to understand how these might affect the parts of the brain that deal with emotion.
Another line of research suggests that bipolar disorder could be linked to a flaw in how cells regulate energy, said Nierenberg.
For many, but not all patients, "there's a higher rate of childhood trauma, childhood abuse and neglect," said Burdick.
Substance abuse is also a risk factor, and women sometimes develop it later in life compared to men.
Lithium, which has been used since the 1940s, is still considered by many clinicians as the "gold standard" despite side effects.
Anti-inflammatory drugs that reduce an abnormal immune response are being investigated as a treatment, but research is preliminary.
Experts have also started to understand the role that the disruption of "social rhythms" play in bipolar disorder, which has shifted more attention toward therapy.
For instance, the death of a pet can trigger a depression-mania cycle, but when scientists studied such events closely, they realized patients were not driven by grief alone.
"Not only did the person suffer psychologically from that loss, but they used to take the dog out for walks,they got exercise, and it also got them up early in the day so that they had social interactions," said Sullivan.
People with bipolar disorder are sensitive to such disruptions, which means events like the coronavirus pandemic and lockdowns can cause particular harm.
"I have actually had one patient who I haven't seen in more than 10 years, who I don't currently treat, who called me up out of the blue and she's clearly manic," said Sullivan.
Support groups like the Depression Bipolar Support Alliance are credited with raising awareness and destigmatizing the illness.
There is thought to be an over-representation of artists, writers and musicians among people with bipolar disorder, a subject explored in the book "Touched with Fire."
"Creative people are distinguished by particularly unique ways of thinking that involve intense emotional experiences" explained Sullivan.
"It may be that that capacity for that sensitivity involves regulatory systems in the brain that also render you vulnerable to mood disorders."
Some patients with bipolar disorder see their condition as an asset, even if it can alienate friends and family.
"Researchers have asked a group of patients with different diagnoses, 'If you had a button that you could press tomorrow and make this go away, would you?' said Burdick.
"And the only group of patients that do not opt, more commonly than not, to press the button, are bipolar patients."
