Two-thirds of people who have bipolar disorder are able to hold a job despite the disruptive mood disorder, according to a new Canadian study.

What appears to make a big difference between having a job or not is the availability of someone to help with the practical necessities of life, according to data from the 2002 Canadian Community Health Survey: Mental Health and Well-being.

An estimated 444,000 people aged 25 to 64 have experienced at least one manic episode suggestive of bipolar disorder. That's about three per cent of the population. More than half of them also suffered a major episode of depression.

People with bipolar I disorder experience manic episodes, which usually feature an elevated mood or unusual euphoria. For example, an individual may start extensive conversations with strangers in public places, or make telephone calls at inappropriate times of night.

Many then sink into the depths of depression. Volatility, alternating between euphoria and irritability, is also common.

Bipolar I disorder can interfere with normal daily activities. People who are affected may experience frequent relapses, and may not return to full function between episodes.

Considering the disruptive impact of the disorder, it is remarkable that 69 per cent of people aged 25 to 64 who had the disorder were employed. And yet, the study found that the likelihood of working was significantly greater for those with higher levels of tangible support.

A support system was associated with the ability to work: The perceived availability of someone to help if an individual needed assistance with meal preparation, daily chores, or getting to appointments.

But more than a quarter of people with bipolar I disorder reported that such help was available either infrequently or not at all.

The first episode signalling bipolar disorder typically happens early in life. About 41 per cent of the people with lifetime bipolar disorder reported their first manic episode, or first major depressive episode in those who had experienced both, occurred before they were 17. The median age of onset was 19.

A relatively large proportion of people with the disorder reported that they had sought professional help for their emotional or mental health, or for an alcohol or drug use problem. More than two-thirds had consulted a family doctor, a psychiatrist or psychologist.

People with bipolar disorder were more likely than those without the condition to have additional mental and emotional problems. And the prevalence of chronic physical conditions was also strikingly high. For example, 15 per cent had asthma, almost double the figure for those without the disorder.

Individuals with bipolar I disorder were also twice as likely to suffer from migraines, and were more likely to be obese.