Symptoms affect mood, sleep, energy, thinking, behaviour and appetite, Kaye says, representing a sudden shift from the person’s usual self.

Kaye’s description of her own experience of the condition is compelling.

Kaye says that in manic periods (bipolar disorder used to be called “manic depression”), “we are elated, ecstatic, reckless, impulsive and volatile. Depending on whether we can channel those emotions, we are either going to feel inspired or agitated. Our judgment is impaired and left untreated, we might hallucinate and experience delusions, often of grandeur.”

‘Understanding the whole person’: long-term bipolar disorder study’s goal

Dr Katrina Rozga, a psychologist at the Jadis Blurton Family Development Centre in Hong Kong, says getting the right diagnosis can be difficult and takes time.

Sometimes, she says, this may be because a person has been diagnosed with depression, “as their manic symptoms are infrequent or they experience hypomania rather than full mania”.

The right diagnosis is very important, stresses Rozga, not just because it might mean the introduction of a medication which makes a difference, but because knowledge is power: the patient and those who love them and live with them will understand better.

It can also just be a huge relief to a person to hear that what they have been struggling with is real and has a name. Selena Gomez expressed relief at her diagnosis: “I felt a huge weight lifted off me. I could take a deep breath and go, ‘OK, that explains so much.’”

‘A life with storms’: bipolar disorder explained by sufferers and experts

So how would you know if you were bipolar? Or somebody you love is? There are four types of the disorder, Rozga explains: bipolar I, bipolar II, cyclothymic disorder and other specified/unspecified bipolar-related disorder.

“The main way they differ is in the severity of symptoms. Typically we look for signs of highs and lows that change and come and go,” she says.

In bipolar I, a person experiences the most severe form of highs and lows, which can last for long periods of time. It is important to remember, Rozga warns, that “highs do not necessarily mean happiness, they can look like irritability and anger as well as happiness, silliness and joy”.

A person in a manic state can also appear to need less sleep, engage in risky behaviour, struggle to remain on topic – or have a flight of ideas and feel invincible or better than others. Mania in bipolar I can be dangerous and include psychosis or a break from reality, including hallucinations.

The low or depressive phase looks a lot like clinical depression and includes the characteristic lethargy, hopelessness and loss of interest in things that used to bring joy.

How anxiety and depression raise the risk of 29 physical health conditions

Bipolar II includes episodes of depression that last at least two weeks and a person experiences less acute mania – called hypomania.

“A person in a hypomanic state may make some rash or risky decisions but won’t experience psychosis or delusions and hallucinations,” Rozga says.

Cyclothymic disorder is a less severe form of bipolar disorder, and someone diagnosed with other unspecified or specified bipolar disorder likely experiences some symptoms associated with bipolar but not enough for a full diagnosis.

There is, says Rozga, a strong genetic component to bipolar disorder.

“Some studies have found that if a parent has bipolar their child has about a 10 per cent chance of developing their illness, and this goes up to 40 per cent if both parents have it.”

Know your family medical history: your health could depend on it

It is important to understand what bipolar disorder really is though, what it means and especially how it presents.

As Kaye says, bipolar disorder is often exaggerated by the media, and that is dangerous because “inaccurate depictions, violent images and demeaning language can feed the stigma, even when it’s presenting the condition in a ‘positive’ way”.

Sure, Kaye says, the character with bipolar disorder is the one saving the world and not the one blowing it up. The reality, she says, is very different – come off your meds and you are just as likely to be hit by depression as mania.

“But that wouldn’t make good television.”

These “cartoonish narratives”, she says, means people tend to apply the most extreme symptoms of bipolar disorder to everybody who has it. But not everyone experiences the same symptoms or with the same severity – for example, a small number might hear voices, but the vast majority never will.

‘People become fear-based’: counselling lonely, depressed men in Hong Kong

Chan (not his real name), a member of Kaye’s support group who has bipolar disorder and wants to protect his privacy, says that because of the way the disorder is portrayed, the public experiences of celebrities such as Kanye West “are subject to scrutiny and ridicule on social media rather than being viewed as moments that warrant genuine concern”.

“Just Google ‘Kanye breakdown’,” he urges.

Kaye agrees. She has mixed feelings about celebrities sharing their diagnoses.

Certainly they help to shine a light on conditions that people might otherwise not come into contact with, know much about or have even heard of. And, she says, “it can be comforting to know that one of your favourite celebrities is going through the same struggles as you”.

“But there are risks. People are fragile. People break.”

“It can change the way you perceive your own condition.”

Important to know, she adds, is that just because a person has a diagnosis of bipolar disorder, does not mean they are either “up” or “down” all the time.

“Most of the time we’re neither. The reality is that most people experience long periods of mood normalcy between episodes that can last months, years – or even the rest of your life.”

Chan has a friend who says she wishes he had never told her about his diagnosis. She says knowing makes her worry he may harm himself one day.

In bookstores, Chan says, there is a dedicated “Self-Help” section. “How about a section specifically focused on ‘Helping Friends?’” he asks.

To really help, you need to be prepared to listen when they are brave enough to speak.