Think of schizophrenia and your mind might wander to the movie A Beautiful Mind that chronicled the struggle of John Forbes Nash, the mathematical genius who struggled with — and overcame — schizophrenia. He was eventually awarded the Nobel Prize. The movie earned four Academy Awards.

Or you might think back to Montreal, where — in the late 1950s and early 1960s — Dr. Ewan Cameron was so driven to find a cure for schizophrenia that he subjected his patients to horrific mind control experiments funded by the U.S. Central Intelligence Agency.

The scientific community has struggled with this complex series of conditions that was only given a name in 1908, when psychiatrist Eugen Bleuler renamed dementia praecox, a condition identified in 1893. Bleuler determined that schizophrenia is not a form of dementia.

What is schizophrenia?

The term comes from a Greek word meaning "split mind."

The condition has no one clearcut definition. Most experts believe it is an extremely complex — and serious — mental disorder that is comprised of many illnesses. A chemical imbalance in the brain may cause symptoms.

The World Health Organization says schizophrenia affects less than one per cent of the adult population — about seven people per thousand, mostly in the age group 15-35 years. Though cases are few and far between, the prevalence is high because it is a chronic condition.

The WHO estimates that 24 million people around the world suffer from schizophrenia.

That works out to about 300,000 people in Canada, according to the Schizophrenia Society of Canada.

What are the symptoms?

There are two types of schizophrenia symptoms: positive and negative. Positive symptoms are regarded as manifestations of psychosis. Among them:

• You become delusional — convinced of things even though they have no basis in fact and are inconsistent with your culture.
• You hallucinate — see, hear, taste, smell or feel things that do not exist.
• Your thoughts are unconnected, making it difficult to clearly communicate with other people.
• Your mood changes drastically — you find it hard to express feelings or you feel empty of any emotions.
• You can't complete mundane tasks like bathing, dressing appropriately or fixing simple meals.

Negative symptoms are the loss or absence of traits or abilities that come normally to most people. They include:

• You become lethargic. You become far less physically active than normal.
• You're unmotivated. You have problems finishing tasks or making long-term plans.
• You lose interest in the feelings and lives of others.
• You don't care how you look.

What causes schizophrenia?

No single cause has been identified.

There is evidence of a genetic link. If it's in your family, your risk of developing schizophrenia may be higher.

There is also some evidence that stressful life events may cause or trigger schizophrenic bouts.

In a study published in the May 3, 2007, issue of the journal Neuron, Toronto researcher Dr. John Roder found a malfunctioning gene can cause schizophrenia. Roder was a high-profile cancer researcher before he changed directions after his son was diagnosed with schizophrenia.

Is there a cure?

There is no cure, but schizophrenia can be managed through treatment, which is most effective when the condition is caught early.

Treatment normally consists of medication and psychosocial intervention — therapy. Drugs used are generally antipsychotic medications, although others may also be prescribed to mange the side-effects of the antipsychotic drugs or to treat other symptoms like depression, anxiety and sleep problems.

The drugs can be highly effective, but they usually have to be taken every day. If patients stop taking their medication, their symptoms will likely return. Often, those patients won't go back on their medication without outside intervention.

What is the prognosis?

It is difficult to tell. Some studies have suggested that up to a third of patients can make a full recovery. Most of the rest can manage with medication.

Do patients have to spend a lot of time in hospital?

Generally, no. Care can normally be provided at the community level, with active family and community involvement.

However, the World Health Organization estimates that more than half of people living with schizophrenia are not receiving adequate care and that 90 per cent of people going without treatment live in developing countries.

"People with schizophrenia can't advocate for themselves," Dr. John Roder, a Toronto-based schizophrenia researcher, told CBC News. "So if Terry Fox would have had schizophrenia, he wouldn't have raised any money for that disorder."