"All the work done over the years trying to de-stigmatise this disease -- it is swept away in 24 hours," Dollfus told AFP.
Around one in every 300 people worldwide are affected by schizophrenia, according to the World Health Organization.
It causes a wide range of distressing delusional disorders, which vary in intensity between patients but often hugely disrupts their lives.
At least five percent of schizophrenia patients are estimated to die by suicide.
The condition is usually treated with a combination of anti-psychotic drugs, social support for reintegration, and psychological therapy.
Scottish psychiatrist Robin Murray, who has spent decades researching schizophrenia, told AFP that when it came to medication, "treatment has not changed dramatically" over the last 20 or 30 years.
He added that psychological therapy had improved in that time.
But unlike numerous other mental disorders -- particularly neurotic conditions -- taking serious drugs remains the cornerstone in treating schizophrenia.
For drugs, there has been a "blank period since the 2010s, when pharmaceutical laboratories really withdrew from psychiatry," Dollfus said.
But there has been some innovation recently, she added.
One development have been apps that can track patients' progress, ensure timely follow-up sessions and contact psychiatrists if necessary.
Another is a new treatment approved by the US Food and Drug Administration last month.
The treatment, developed by the Israeli pharmaceutical firm Teva and France's MedinCell, involves the drug risperidone which has long been used for schizophrenia.
It has traditionally been prescribed as a daily pill, but the new treatment is administered via injection, allowing the drug to be gradually released in the body over several weeks.
This makes it impossible for patients to miss a daily pill.
Interruptions to medication, often brought about by the psychosis the illness causes, are a common problem in treating schizophrenia.
For example, the attacker in Reims had been off his medication, according to several sources.
This new way of administering an old medication is not the kind of revolution that a new drug would represent. But progress may soon be made in that area.
Dollfus said that some drugs currently being investigated are "really interesting" because they work in a different way than those of the past.
Traditionally, anti-psychotic drugs used to treat schizophrenia aim to block the action of dopamine, a molecule that acts as a chemical messenger in the brain.
However, dopamine seems to play a complex role in schizophrenia -- some patients can have excessive levels in some respects and insufficient levels in others.
Traditional anti-psychotic drugs, which tend to work well at stopping certain symptoms such as hallucinations, do not help in other areas, such as the loss of willpower or struggles with language and speech.
Recent research has focused on finding other molecules which regulate rather than block dopamine, while also acting on other areas thought to be involved in schizophrenia.
These treatments, such as one that targets a protein called TAAR1, are still some way away from being available to patients.
But the TAAR1 drug has had positive results from the most advanced stage of trials, known as phase 3.
"This is a really promising avenue," Dollfus said.
© 2023 AFP