By: June Cheong

What do late American president Theodore Roosevelt, actress Carrie Fisher and pop star Britney Spears have in common?

They all suffer from bipolar disorder.

This mood disorder is characterised by recurrent bouts of extreme mood changes.

Dr Adrian Wang, a consultant psychiatrist at Dr Adrian Wang Psychiatric And Counselling Care, said: 'It's a brain disorder because it is caused by chemical imbalances.'

While the mood swings make it appear to be psychological, the cause is biological, he said.

Patients veer between two psychological states - mania and melancholia.

When manic, the patient may be in excessively high spirits, is sometimes irritable, needs less sleep with thoughts racing through his brain constantly, talks quickly and makes grand plans.

Symptoms of melancholia are a persistent feeling of sadness, hopelessness and lethargy. He may be unable to eat or sleep.

Dr Ng Beng Yeong, the head of the department of psychiatry at Singapore General Hospital, said: 'In extreme forms (of mania), they may believe they are exceptionally gifted or rich or are important religious, political or famous people.

'The judgment of those with mania is often impaired because of grandiosity and failure to plan or consider the consequences of their actions.'

Mania often requires hospital admission as the manic patient's energy levels may be too much for their family or caregivers to take. The manic patient is also often prone then to excessive or dangerous but pleasurable behaviours like spending too much or sexual indiscretion.

While manic patients invariably sound like they have more fun, Dr Wang noted that depressive lows often last longer than manic highs.

Dr Chua Tze Ern, a registrar in the department of community psychiatry at the Institute of Mental Health, said: 'Different individuals will have different symptoms. One may be predominantly depressed and another may be predominantly manic.'

In between high and low episodes, patients feel well and normal - like everyone else.

The exact cause of bipolar disorder is unknown but doctors believe it is likely to be caused by a plethora of factors interacting with one another.

Dr Ng said: 'It often runs in families and there is a genetic component to the disorder.

'However, even though someone may have inherited the genes for bipolar disorder, there is no guarantee that he will develop it.'

As the brain controls moods, sense of perception and judgment, imbalances in certain brain chemicals like dopamine and serotonin may result in bipolar disorder. These may be destabilised due to genetics.

Beyond this genes factor, stressful or negative life events like losing a loved one and certain personality traits like being neurotic can also predispose someone to developing bipolar disorder.

A stressful event often triggers the first episode of bipolar disorder, so how one copes with stress and negative experiences influences one's susceptibility to the disorder.

Dr Wang said: 'The current economic crisis is stressful for everyone and stress can unmask underlying disorders.

'I've seen an increase in the number of patients with mood or anxiety problems.'

Asked if bipolar disorder can be prevented, Dr Ng said: 'Stay away from drugs, learn to manage stressful events better and give priority to sleep. Loss of sleep can contribute to the onset and recurrence of depression and mania.'

Although women are more prone to getting mood disorders like depression and anxiety, bipolar disorder seems 'neutral' to gender.

It is most common in people between the ages of 20 and 40 and 1 per cent of adults in Singapore have bipolar disorder.