Imagine for a minute what life might have been like if you'd been diagnosed with schizophrenia in 1911. Shunned by society, you would have been treated with fear and suspicion by many.

With no known cure, you would be subjected to treatment by trial and error, some of which would have gruesome side-effects. Detained by the state, you could expect to be monitored by overworked, underpaid staff and going to church might have been suggested as a way to calm your chaotic mind.

A lot has changed in the 100 years since the term "schizophrenia" was first coined, but perhaps not quite as much as you might think. People living with schizophrenia still experience many of the same problems today.

In 1910, Winston Churchill summed up contemporary attitudes when he wrote to the prime minister, Herbert Asquith, arguing for the mass sterilisation of people with severe mental illness.

Churchill warned that the "feeble-minded and insane classes" constituted a "danger which it is impossible to exaggerate", and that "the source from which the stream of madness is fed should be cut off and sealed up before another year has passed."

While views like these are no longer part of mainstream debate, the stigma and discrimination people with schizophrenia still face can be worse than the symptoms of the illness itself. Sensationalist media reporting has helped paint a picture of "schizos" who are wild, dangerous and need to be controlled.

In truth, violence is not a symptom of schizophrenia and people who have it are far more likely to harm themselves than anybody else. The vast majority of those affected live very ordinary lives, managing their symptoms through a combination of medication and, if they're lucky, talking therapies.

While huge advances in treatment have been made since the early 1900s when "cures" included raising patients' body temperature by injecting them with sulphur and oil, things haven't progressed anywhere near as fast as they have for physical illnesses such as cancer and heart disease.

Treatment today can still be a long and draining process of trial and error to find the right medication, which can last for years. While the drugs may dull symptoms, the side effects can include rapid weight gain, heart problems, loss of sex drive and a greater risk of developing diabetes. The effects of medication, along with lifestyle factors, mean people with schizophrenia die up to 20 years earlier than the rest of us, mostly from preventable physical illness.

Too often, people with severe mental illnesses are fobbed off with drugs alone. There are plenty of other treatments proven to work, but a poll by my organisation, Rethink Mental Illness, found just 16% of people who have schizophrenia and bipolar disorder are getting access to all the treatment recommended by Nice for their diagnosis.

One of our activists, David Strange – who developed paranoid schizophrenia while completing his doctorate at Oxford – was offered nothing but medication for 10 years after first being diagnosed. When he finally made it to the top of the waiting list for cognitive behavioural therapy last year, it changed his life. He still experiences frightening auditory and visual hallucinations, but it has helped him learn to engage with them and challenge what they say.

Although the conditions found in the old "lunatic asylums" are a far cry from inpatient care today, there are some striking similarities.

In 1908, manic-depressive Clifford Beers published an account of his experiences of institutionalisation. In it he describes crowded wards staffed by staff too busy and stressed to properly communicate with patients. For many who have experienced inpatient care in 2011, his observations will be depressingly familiar.

As for the suggestion that church might be the answer to mental illness, this advice was recently given to one of our supporters by a nurse and it wasn't an isolated incident. Our members have told us countless similar stories of inconsiderate or ignorant comments. These words reveal the stigma and misunderstanding that still surrounds mental illness, sometimes even among health professionals.

To mark the unhappy 100th birthday of the term "schizophrenia", Rethink Mental illness will be launching a campaign on Tuesday asking people to send a clear message to government that people with schizophrenia deserve a better deal in every area of their lives.