Thousands of Canadians who have epilepsy may be living for years without a diagnosis because doctors unfamiliar with the symptoms believe patients have another illness.

While many associate epilepsy with severe seizures, about 80 per cent of patients suffer from mild seizures that are harder to spot, or notice strange smells or experience an odd taste in their mouths.

These signs can go unnoticed by doctors, many of whom are not adequately trained in the number of ways epilepsy can present itself, according to experts.

"Everyone knows about the epileptic seizures where you fall and shake and froth at the mouth and bite your tongue. That is easy," Dr. Peter Carlen, of the Krembil Neuroscience Centre at Toronto Western Hospital, told CTV News. "But in fact, the most common type of epileptic seizures are when you are not there, or you are a little bit confused."

Experts cannot say exactly how many Canadians suffer from epilepsy or another form of seizure disorder. However, estimates range from 120,000 to 245,000 in Ontario alone.

It is that wide range of possible cases that worries experts because patients will miss out on treatment, or could be undergoing treatment for a condition they don't have.

Adam Cunningham of Burlington, Ont., began suffering seizures when he was eight years old.

"I was having as much as 10 a day and I felt like somebody was bashing my head in with a baseball bat," Cunningham, now 31, told CTV News.

It was even suggested to him that he might have epilepsy, but doctors insisted that wasn't the case because his test results were always negative, he said.

It took 22 years for Cunningham to find a doctor who gave him the correct diagnosis. In the meantime, he lost hockey and lacrosse scholarships to leading U.S. schools because no one could explain the origins of his frequent, but less violent, seizures.

Even though he is now on medication that has drastically reduced his seizures, Cunningham can't live alone and can't drive.

Carlen said many other patients wait 20 years or more for a diagnosis because there are not enough specialists in Canada trained to spot epilepsy's symptoms.

While the more subtle symptoms may be hard for any physician to notice, "doctors have to educate themselves more in this disease," Carlen said.

Cunningham will undergo brain surgery in December in the hope of permanently eliminating his seizures, but hopes his story can help others who may be suffering unknowingly with epilepsy.

"I don't want this to happen to other people," Cunningham said. "It has been a terrible impact on my life and I don't want this to happen to anyone else."

With a report from CTV medical specialist Avis Favaro and senior producer Elizabeth St. Philip