More than a million Canadians are dealing with conditions that cannot be identified by medical tests or physical exams, Statistics Canada said Friday.

The agency looked at data from 2002 and 2003 for people aged 12 and over.

It found five per cent of Canadians are dealing with medically unexplained physical symptoms such as chronic fatigue syndrome, fibromyalgia and multiple chemical sensitivity.

About 1.3 per cent of the population reported chronic fatigue syndrome, which is characterized by extreme tiredness.

About 1.5 per cent reported fibromyalgia, which involves pain lasting three months or more in at least 11 of 18 specified areas.

About 2.4 per cent reported multiple chemical sensitivity. People with the disorder develop a variety of symptoms when they are exposed to synthetic chemicals in doses that usually have no noticeable effect.

The three conditions were more common among people in lower-income households compared with wealthier Canadians.

More than 25 per cent of people with medically unexplained symptoms needed help with everyday activities, such as preparing meals or running errands. Among people who did not report any of the conditions, the proportion was seven per cent.

About one-fifth of them were also dealing with at least one psychiatric disorder, such as depression or panic disorder.